Class: BigDecimal

Inherits:
Numeric
  • Object
show all
Defined in:
ext/bigdecimal/bigdecimal.c,
lib/bigdecimal.rb,
lib/bigdecimal.rb,
lib/bigdecimal/util.rb,
ext/bigdecimal/bigdecimal.c

Overview

BigDecimal provides arbitrary-precision floating point decimal arithmetic.

Introduction

Ruby provides built-in support for arbitrary precision integer arithmetic.

For example:

42**13 #=> 1265437718438866624512

BigDecimal provides similar support for very large or very accurate floating point numbers.

Decimal arithmetic is also useful for general calculation, because it provides the correct answers people expect–whereas normal binary floating point arithmetic often introduces subtle errors because of the conversion between base 10 and base 2.

For example, try:

sum = 0
10_000.times do
  sum = sum + 0.0001
end
print sum #=> 0.9999999999999062

and contrast with the output from:

require 'bigdecimal'

sum = BigDecimal("0")
10_000.times do
  sum = sum + BigDecimal("0.0001")
end
print sum #=> 0.1E1

Similarly:

(BigDecimal(“1.2”) - BigDecimal(“1.0”)) == BigDecimal(“0.2”) #=> true

(1.2 - 1.0) == 0.2 #=> false

A Note About Precision

For a calculation using a BigDecimal and another value, the precision of the result depends on the type of value:

  • If value is a Float, the precision is Float::DIG + 1.

  • If value is a Rational, the precision is larger than Float::DIG + 1.

  • If value is a BigDecimal, the precision is value‘s precision in the internal representation, which is platform-dependent.

  • If value is other object, the precision is determined by the result of BigDecimal(value).

Special features of accurate decimal arithmetic

Because BigDecimal is more accurate than normal binary floating point arithmetic, it requires some special values.

Infinity

BigDecimal sometimes needs to return infinity, for example if you divide a value by zero.

BigDecimal(“1.0”) / BigDecimal(“0.0”) #=> Infinity BigDecimal(“-1.0”) / BigDecimal(“0.0”) #=> -Infinity

You can represent infinite numbers to BigDecimal using the strings 'Infinity', '+Infinity' and '-Infinity' (case-sensitive)

Not a Number

When a computation results in an undefined value, the special value NaN (for ‘not a number’) is returned.

Example:

BigDecimal(“0.0”) / BigDecimal(“0.0”) #=> NaN

You can also create undefined values.

NaN is never considered to be the same as any other value, even NaN itself:

n = BigDecimal(‘NaN’) n == 0.0 #=> false n == n #=> false

Positive and negative zero

If a computation results in a value which is too small to be represented as a BigDecimal within the currently specified limits of precision, zero must be returned.

If the value which is too small to be represented is negative, a BigDecimal value of negative zero is returned.

BigDecimal(“1.0”) / BigDecimal(“-Infinity”) #=> -0.0

If the value is positive, a value of positive zero is returned.

BigDecimal(“1.0”) / BigDecimal(“Infinity”) #=> 0.0

(See BigDecimal.mode for how to specify limits of precision.)

Note that -0.0 and 0.0 are considered to be the same for the purposes of comparison.

Note also that in mathematics, there is no particular concept of negative or positive zero; true mathematical zero has no sign.

bigdecimal/util

When you require bigdecimal/util, the #to_d method will be available on BigDecimal and the native Integer, Float, Rational, String, Complex, and NilClass classes:

require ‘bigdecimal/util’

42.to_d                         # => 0.42e2
0.5.to_d                        # => 0.5e0
(2/3r).to_d(3)                  # => 0.667e0
"0.5".to_d                      # => 0.5e0
Complex(0.1234567, 0).to_d(4)   # => 0.1235e0
nil.to_d                        # => 0.0

Methods for Working with JSON

  • ::json_create: Returns a new BigDecimal object constructed from the given object.

  • #as_json: Returns a 2-element hash representing self.

  • #to_json: Returns a JSON string representing self.

These methods are provided by the JSON gem. To make these methods available:

require 'json/add/bigdecimal'

  • License

Copyright © 2002 by Shigeo Kobayashi <[email protected]>.

BigDecimal is released under the Ruby and 2-clause BSD licenses. See LICENSE.txt for details.

Maintained by mrkn <[email protected]> and ruby-core members.

Documented by zzak <[email protected]>, mathew <[email protected]>, and many other contributors.

Defined Under Namespace

Modules: Internal

Constant Summary collapse

VERSION =

The version of bigdecimal library

rb_str_new2(BIGDECIMAL_VERSION)
BASE =

Base value used in internal calculations. On a 32 bit system, BASE is 10000, indicating that calculation is done in groups of 4 digits. (If it were larger, BASE**2 wouldn’t fit in 32 bits, so you couldn’t guarantee that two groups could always be multiplied together without overflow.)

INT2FIX((SIGNED_VALUE)BASE)
EXCEPTION_ALL =

Determines whether overflow, underflow or zero divide result in an exception being thrown. See BigDecimal.mode.

0xff
EXCEPTION_NaN =

Determines what happens when the result of a computation is not a number (NaN). See BigDecimal.mode.

0x02
EXCEPTION_INFINITY =

Determines what happens when the result of a computation is infinity. See BigDecimal.mode.

0x01
EXCEPTION_UNDERFLOW =

Determines what happens when the result of a computation is an underflow (a result too small to be represented). See BigDecimal.mode.

0x04
EXCEPTION_OVERFLOW =

Determines what happens when the result of a computation is an overflow (a result too large to be represented). See BigDecimal.mode.

0x01
EXCEPTION_ZERODIVIDE =

Determines what happens when a division by zero is performed. See BigDecimal.mode.

0x10
ROUND_MODE =

Determines what happens when a result must be rounded in order to fit in the appropriate number of significant digits. See BigDecimal.mode.

0x100
ROUND_UP =

Indicates that values should be rounded away from zero. See BigDecimal.mode.

1
ROUND_DOWN =

Indicates that values should be rounded towards zero. See BigDecimal.mode.

2
ROUND_HALF_UP =

Indicates that digits >= 5 should be rounded up, others rounded down. See BigDecimal.mode.

3
ROUND_HALF_DOWN =

Indicates that digits >= 6 should be rounded up, others rounded down. See BigDecimal.mode.

4
ROUND_CEILING =

Round towards +Infinity. See BigDecimal.mode.

5
ROUND_FLOOR =

Round towards -Infinity. See BigDecimal.mode.

6
ROUND_HALF_EVEN =

Round towards the even neighbor. See BigDecimal.mode.

7
SIGN_NaN =

Indicates that a value is not a number. See BigDecimal.sign.

0
SIGN_POSITIVE_ZERO =

Indicates that a value is +0. See BigDecimal.sign.

1
SIGN_NEGATIVE_ZERO =

Indicates that a value is -0. See BigDecimal.sign.

-1
SIGN_POSITIVE_FINITE =

Indicates that a value is positive and finite. See BigDecimal.sign.

2
SIGN_NEGATIVE_FINITE =

Indicates that a value is negative and finite. See BigDecimal.sign.

-2
SIGN_POSITIVE_INFINITE =

Indicates that a value is positive and infinite. See BigDecimal.sign.

3
SIGN_NEGATIVE_INFINITE =

Indicates that a value is negative and infinite. See BigDecimal.sign.

-3
INFINITY =

BigDecimal@Infinity] value.

Positive infinity[rdoc-ref
NAN =

BigDecimal@Not+a+Number]‘ value.

'{Not a Number}[rdoc-ref

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

._load(str) ⇒ Object

Internal method used to provide marshalling support. See the Marshal module.



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# File 'ext/bigdecimal/bigdecimal.c', line 691

static VALUE
BigDecimal_load(VALUE self, VALUE str)
{
    BDVALUE v;
    unsigned char *pch;
    unsigned char ch;

    pch = (unsigned char *)StringValueCStr(str);
    /* First skip max prec. Don't trust the value. */
    while((*pch) != (unsigned char)'\0' && (ch = *pch++) != (unsigned char)':') {
        if(!ISDIGIT(ch)) {
            rb_raise(rb_eTypeError, "load failed: invalid character in the marshaled string");
        }
    }
    v = bdvalue_nonnullable(CreateFromString((char *)pch, self, true, true));
    return CheckGetValue(v);
}

.double_fig ⇒ Object

.interpret_loosely(string) ⇒ Object

Returns the BigDecimal converted loosely from string.



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# File 'ext/bigdecimal/bigdecimal.c', line 3030

static VALUE
BigDecimal_s_interpret_loosely(VALUE klass, VALUE str)
{
    char const *c_str = StringValueCStr(str);
    NULLABLE_BDVALUE v = CreateFromString(c_str, klass, false, true);
    if (v.bigdecimal_or_nil == Qnil)
        return Qnil;
    else
        return CheckGetValue(bdvalue_nonnullable(v));
}

.limit(digits) ⇒ Object

Limit the number of significant digits in newly created BigDecimal numbers to the specified value. Rounding is performed as necessary, as specified by BigDecimal.mode.

A limit of 0, the default, means no upper limit.

The limit specified by this method takes less priority over any limit specified to instance methods such as ceil, floor, truncate, or round.



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# File 'ext/bigdecimal/bigdecimal.c', line 3054

static VALUE
BigDecimal_limit(int argc, VALUE *argv, VALUE self)
{
    VALUE  nFig;
    VALUE  nCur = SIZET2NUM(VpGetPrecLimit());

    if (rb_scan_args(argc, argv, "01", &nFig) == 1) {
	int nf;
	if (NIL_P(nFig)) return nCur;
	nf = NUM2INT(nFig);
	if (nf < 0) {
	    rb_raise(rb_eArgError, "argument must be positive");
	}
	VpSetPrecLimit(nf);
    }
    return nCur;
}

.mode(mode, setting = nil) ⇒ Integer

Returns an integer representing the mode settings for exception handling and rounding.

These modes control exception handling:

  • BigDecimal::EXCEPTION_NaN.

  • BigDecimal::EXCEPTION_INFINITY.

  • BigDecimal::EXCEPTION_UNDERFLOW.

  • BigDecimal::EXCEPTION_OVERFLOW.

  • BigDecimal::EXCEPTION_ZERODIVIDE.

  • BigDecimal::EXCEPTION_ALL.

Values for setting for exception handling:

  • true: sets the given mode to true.

  • false: sets the given mode to false.

  • nil: does not modify the mode settings.

You can use method BigDecimal.save_exception_mode to temporarily change, and then automatically restore, exception modes.

For clarity, some examples below begin by setting all exception modes to false.

This mode controls the way rounding is to be performed:

  • BigDecimal::ROUND_MODE

You can use method BigDecimal.save_rounding_mode to temporarily change, and then automatically restore, the rounding mode.

NaNs

Mode BigDecimal::EXCEPTION_NaN controls behavior when a BigDecimal NaN is created.

Settings:

  • false (default): Returns BigDecimal('NaN').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
BigDecimal('NaN')                                 # => NaN
BigDecimal.mode(BigDecimal::EXCEPTION_NaN, true)  # => 2
BigDecimal('NaN') # Raises FloatDomainError

Infinities

Mode BigDecimal::EXCEPTION_INFINITY controls behavior when a BigDecimal Infinity or -Infinity is created. Settings:

  • false (default): Returns BigDecimal('Infinity') or BigDecimal('-Infinity').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false)     # => 0
BigDecimal('Infinity')                                # => Infinity
BigDecimal('-Infinity')                               # => -Infinity
BigDecimal.mode(BigDecimal::EXCEPTION_INFINITY, true) # => 1
BigDecimal('Infinity')  # Raises FloatDomainError
BigDecimal('-Infinity') # Raises FloatDomainError

Underflow

Mode BigDecimal::EXCEPTION_UNDERFLOW controls behavior when a BigDecimal underflow occurs. Settings:

  • false (default): Returns BigDecimal('0') or BigDecimal('-Infinity').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false)      # => 0
def flow_under
  x = BigDecimal('0.1')
  100.times { x *= x }
end
flow_under                                             # => 100
BigDecimal.mode(BigDecimal::EXCEPTION_UNDERFLOW, true) # => 4
flow_under # Raises FloatDomainError

Overflow

Mode BigDecimal::EXCEPTION_OVERFLOW controls behavior when a BigDecimal overflow occurs. Settings:

  • false (default): Returns BigDecimal('Infinity') or BigDecimal('-Infinity').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false)     # => 0
def flow_over
  x = BigDecimal('10')
  100.times { x *= x }
end
flow_over                                             # => 100
BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, true) # => 1
flow_over # Raises FloatDomainError

Zero Division

Mode BigDecimal::EXCEPTION_ZERODIVIDE controls behavior when a zero-division occurs. Settings:

  • false (default): Returns BigDecimal('Infinity') or BigDecimal('-Infinity').

  • true: Raises FloatDomainError.

Examples:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false)       # => 0
one = BigDecimal('1')
zero = BigDecimal('0')
one / zero                                              # => Infinity
BigDecimal.mode(BigDecimal::EXCEPTION_ZERODIVIDE, true) # => 16
one / zero # Raises FloatDomainError

All Exceptions

Mode BigDecimal::EXCEPTION_ALL controls all of the above:

BigDecimal.mode(BigDecimal::EXCEPTION_ALL, false) # => 0
BigDecimal.mode(BigDecimal::EXCEPTION_ALL, true)  # => 23

Rounding

Mode BigDecimal::ROUND_MODE controls the way rounding is to be performed; its setting values are:

  • ROUND_UP: Round away from zero. Aliased as :up.

  • ROUND_DOWN: Round toward zero. Aliased as :down and :truncate.

  • ROUND_HALF_UP: Round toward the nearest neighbor; if the neighbors are equidistant, round away from zero. Aliased as :half_up and :default.

  • ROUND_HALF_DOWN: Round toward the nearest neighbor; if the neighbors are equidistant, round toward zero. Aliased as :half_down.

  • ROUND_HALF_EVEN (Banker’s rounding): Round toward the nearest neighbor; if the neighbors are equidistant, round toward the even neighbor. Aliased as :half_even and :banker.

  • ROUND_CEILING: Round toward positive infinity. Aliased as :ceiling and :ceil.

  • ROUND_FLOOR: Round toward negative infinity. Aliased as :floor:.

Returns:



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# File 'ext/bigdecimal/bigdecimal.c', line 943

static VALUE
BigDecimal_mode(int argc, VALUE *argv, VALUE self)
{
    VALUE which;
    VALUE val;
    unsigned long f,fo;

    rb_scan_args(argc, argv, "11", &which, &val);
    f = (unsigned long)NUM2INT(which);

    if (f & VP_EXCEPTION_ALL) {
	/* Exception mode setting */
	fo = VpGetException();
	if (val == Qnil) return INT2FIX(fo);
	if (val != Qfalse && val!=Qtrue) {
	    rb_raise(rb_eArgError, "second argument must be true or false");
	    return Qnil; /* Not reached */
	}
	if (f & VP_EXCEPTION_INFINITY) {
	    VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_INFINITY) :
			(fo & (~VP_EXCEPTION_INFINITY))));
	}
	fo = VpGetException();
	if (f & VP_EXCEPTION_NaN) {
	    VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_NaN) :
			(fo & (~VP_EXCEPTION_NaN))));
	}
	fo = VpGetException();
	if (f & VP_EXCEPTION_UNDERFLOW) {
	    VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_UNDERFLOW) :
			(fo & (~VP_EXCEPTION_UNDERFLOW))));
	}
	fo = VpGetException();
	if(f & VP_EXCEPTION_ZERODIVIDE) {
	    VpSetException((unsigned short)((val == Qtrue) ? (fo | VP_EXCEPTION_ZERODIVIDE) :
			(fo & (~VP_EXCEPTION_ZERODIVIDE))));
	}
	fo = VpGetException();
	return INT2FIX(fo);
    }
    if (VP_ROUND_MODE == f) {
	/* Rounding mode setting */
	unsigned short sw;
	fo = VpGetRoundMode();
	if (NIL_P(val)) return INT2FIX(fo);
	sw = check_rounding_mode(val);
	fo = VpSetRoundMode(sw);
	return INT2FIX(fo);
    }
    rb_raise(rb_eTypeError, "first argument for BigDecimal.mode invalid");
    return Qnil;
}

.save_exception_mode { ... } ⇒ Object

Execute the provided block, but preserve the exception mode

BigDecimal.save_exception_mode do
  BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
  BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)

  BigDecimal(BigDecimal('Infinity'))
  BigDecimal(BigDecimal('-Infinity'))
  BigDecimal(BigDecimal('NaN'))
end

For use with the BigDecimal::EXCEPTION_*

See BigDecimal.mode

Yields:



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# File 'ext/bigdecimal/bigdecimal.c', line 3115

static VALUE
BigDecimal_save_exception_mode(VALUE self)
{
    unsigned short const exception_mode = VpGetException();
    int state;
    VALUE ret = rb_protect(rb_yield, Qnil, &state);
    VpSetException(exception_mode);
    if (state) rb_jump_tag(state);
    return ret;
}

.save_limit { ... } ⇒ Object

Execute the provided block, but preserve the precision limit

BigDecimal.limit(100)
puts BigDecimal.limit
BigDecimal.save_limit do
    BigDecimal.limit(200)
    puts BigDecimal.limit
end
puts BigDecimal.limit

Yields:



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# File 'ext/bigdecimal/bigdecimal.c', line 3165

static VALUE
BigDecimal_save_limit(VALUE self)
{
    size_t const limit = VpGetPrecLimit();
    int state;
    VALUE ret = rb_protect(rb_yield, Qnil, &state);
    VpSetPrecLimit(limit);
    if (state) rb_jump_tag(state);
    return ret;
}

.save_rounding_mode { ... } ⇒ Object

Execute the provided block, but preserve the rounding mode

BigDecimal.save_rounding_mode do
  BigDecimal.mode(BigDecimal::ROUND_MODE, :up)
  puts BigDecimal.mode(BigDecimal::ROUND_MODE)
end

For use with the BigDecimal::ROUND_*

See BigDecimal.mode

Yields:



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# File 'ext/bigdecimal/bigdecimal.c', line 3140

static VALUE
BigDecimal_save_rounding_mode(VALUE self)
{
    unsigned short const round_mode = VpGetRoundMode();
    int state;
    VALUE ret = rb_protect(rb_yield, Qnil, &state);
    VpSetRoundMode(round_mode);
    if (state) rb_jump_tag(state);
    return ret;
}

Instance Method Details

#% ⇒ Object

%: a%b = a - (a.to_f/b).floor * b



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# File 'ext/bigdecimal/bigdecimal.c', line 1782

static VALUE
BigDecimal_mod(VALUE self, VALUE r) /* %: a%b = a - (a.to_f/b).floor * b */
{
    NULLABLE_BDVALUE div, mod;

    if (BigDecimal_DoDivmod(self, r, &div, &mod, false)) {
        return CheckGetValue(bdvalue_nonnullable(mod));
    }
    return DoSomeOne(self, r, '%');
}

#*(b) ⇒ Object

Multiply by the specified value.

The result precision will be the precision of the sum of each precision.

See BigDecimal#mult.



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# File 'ext/bigdecimal/bigdecimal.c', line 1576

static VALUE
BigDecimal_mult(VALUE self, VALUE r)
{
    if (!is_coerceable_to_BigDecimal(r)) return DoSomeOne(self, r, '*');
    return BigDecimal_mult_with_coerce(self, r, 0);
}

#**(y) ⇒ Object

call-seq:

  self ** other -> bigdecimal

Returns the \BigDecimal value of +self+ raised to power +other+:

  b = BigDecimal('3.14')
  b ** 2              # => 0.98596e1
  b ** 2.0            # => 0.98596e1
  b ** Rational(2, 1) # => 0.98596e1

Related: BigDecimal#power.



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# File 'lib/bigdecimal.rb', line 77

def **(y)
  case y
  when BigDecimal, Integer, Float, Rational
    power(y)
  when nil
    raise TypeError, 'wrong argument type NilClass'
  else
    x, y = y.coerce(self)
    x**y
  end
end

#+(value) ⇒ Object

Returns the BigDecimal sum of self and value:

b = BigDecimal('111111.111') # => 0.111111111e6
b + 2                        # => 0.111113111e6
b + 2.0                      # => 0.111113111e6
b + Rational(2, 1)           # => 0.111113111e6
b + Complex(2, 0)            # => (0.111113111e6+0i)

See the Note About Precision.



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# File 'ext/bigdecimal/bigdecimal.c', line 1284

static VALUE
BigDecimal_add(VALUE self, VALUE r)
{
    if (!is_coerceable_to_BigDecimal(r)) return DoSomeOne(self, r, '+');
    return BigDecimal_addsub_with_coerce(self, r, 0, +1);
}

#+ ⇒ self

Returns self:

+BigDecimal(5)  # => 0.5e1
+BigDecimal(-5) # => -0.5e1

Returns:

  • (self) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1253

static VALUE
BigDecimal_uplus(VALUE self)
{
    return self;
}

#-(value) ⇒ Object

Returns the BigDecimal difference of self and value:

b = BigDecimal('333333.333') # => 0.333333333e6
b - 2                        # => 0.333331333e6
b - 2.0                      # => 0.333331333e6
b - Rational(2, 1)           # => 0.333331333e6
b - Complex(2, 0)            # => (0.333331333e6+0i)

See the Note About Precision.



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# File 'ext/bigdecimal/bigdecimal.c', line 1338

static VALUE
BigDecimal_sub(VALUE self, VALUE r)
{
    if (!is_coerceable_to_BigDecimal(r)) return DoSomeOne(self, r, '-');
    return BigDecimal_addsub_with_coerce(self, r, 0, -1);
}

#- ⇒ Object

Returns the BigDecimal negation of self:

b0 = BigDecimal('1.5')
b1 = -b0 # => -0.15e1
b2 = -b1 # => 0.15e1



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# File 'ext/bigdecimal/bigdecimal.c', line 1556

static VALUE
BigDecimal_neg(VALUE self)
{
    BDVALUE a = GetBDValueMust(self);
    BDVALUE c = NewZeroWrap(1, a.real->Prec * BASE_FIG);
    VpAsgn(c.real, a.real, -10);
    RB_GC_GUARD(a.bigdecimal);
    return CheckGetValue(c);
}

#/ ⇒ Object

For c = self/r: with round operation



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# File 'ext/bigdecimal/bigdecimal.c', line 1618

static VALUE
BigDecimal_div(VALUE self, VALUE r)
/* For c = self/r: with round operation */
{
    if (!is_coerceable_to_BigDecimal(r)) return DoSomeOne(self, r, '/');
    return BigDecimal_div2(self, r, INT2FIX(0));
}

#<(other) ⇒ Boolean

Returns true if self is less than other, false otherwise:

b = BigDecimal('1.5') # => 0.15e1
b < 2                 # => true
b < 2.0               # => true
b < Rational(2, 1)    # => true
b < 1.5               # => false

Raises an exception if the comparison cannot be made.

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1476

static VALUE
BigDecimal_lt(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '<');
}

#<=(other) ⇒ Boolean

Returns true if self is less or equal to than other, false otherwise:

b = BigDecimal('1.5') # => 0.15e1
b <= 2                # => true
b <= 2.0              # => true
b <= Rational(2, 1)   # => true
b <= 1.5              # => true
b < 1                 # => false

Raises an exception if the comparison cannot be made.

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1497

static VALUE
BigDecimal_le(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, 'L');
}

#<=>(r) ⇒ Object

The comparison operator. a <=> b is 0 if a == b, 1 if a > b, -1 if a < b.



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# File 'ext/bigdecimal/bigdecimal.c', line 1440

static VALUE
BigDecimal_comp(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '*');
}

#==(r) ⇒ Object

Tests for value equality; returns true if the values are equal.

The == and === operators and the eql? method have the same implementation for BigDecimal.

Values may be coerced to perform the comparison:

BigDecimal('1.0') == 1.0  #=> true



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# File 'ext/bigdecimal/bigdecimal.c', line 1456

static VALUE
BigDecimal_eq(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '=');
}

#===(r) ⇒ Object

Tests for value equality; returns true if the values are equal.

The == and === operators and the eql? method have the same implementation for BigDecimal.

Values may be coerced to perform the comparison:

BigDecimal('1.0') == 1.0  #=> true



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# File 'ext/bigdecimal/bigdecimal.c', line 1456

static VALUE
BigDecimal_eq(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '=');
}

#>(other) ⇒ Boolean

Returns true if self is greater than other, false otherwise:

b = BigDecimal('1.5')
b > 1              # => true
b > 1.0            # => true
b > Rational(1, 1) # => true
b > 2              # => false

Raises an exception if the comparison cannot be made.

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1517

static VALUE
BigDecimal_gt(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '>');
}

#>=(other) ⇒ Boolean

Returns true if self is greater than or equal to other, false otherwise:

b = BigDecimal('1.5')
b >= 1              # => true
b >= 1.0            # => true
b >= Rational(1, 1) # => true
b >= 1.5            # => true
b > 2               # => false

Raises an exception if the comparison cannot be made.

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1538

static VALUE
BigDecimal_ge(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, 'G');
}

#_decimal_shift(v) ⇒ Object

Returns self * 10**v without changing the precision.

This method is currently for internal use.

BigDecimal("0.123e10")._decimal_shift(20) #=> "0.123e30"
BigDecimal("0.123e10")._decimal_shift(-20) #=> "0.123e-10"



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# File 'lib/bigdecimal.rb', line 5

def _decimal_shift(i) # :nodoc:
  to_java.move_point_right(i).to_d
end

#_dump ⇒ String

Returns a string representing the marshalling of self. See module Marshal.

inf = BigDecimal('Infinity') # => Infinity
dumped = inf._dump           # => "9:Infinity"
BigDecimal._load(dumped)     # => Infinity

Returns:



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# File 'ext/bigdecimal/bigdecimal.c', line 666

static VALUE
BigDecimal_dump(int argc, VALUE *argv, VALUE self)
{
    BDVALUE v;
    char *psz;
    VALUE dummy;
    volatile VALUE dump;
    size_t len;

    rb_scan_args(argc, argv, "01", &dummy);
    v = GetBDValueMust(self);
    dump = rb_str_new(0, VpNumOfChars(v.real, "E")+50);
    psz = RSTRING_PTR(dump);
    snprintf(psz, RSTRING_LEN(dump), "%"PRIuSIZE":", v.real->Prec*VpBaseFig());
    len = strlen(psz);
    VpToString(v.real, psz+len, RSTRING_LEN(dump)-len, 0, 0);
    rb_str_resize(dump, strlen(psz));

    RB_GC_GUARD(v.bigdecimal);
    return dump;
}

#abs ⇒ Object

Returns the BigDecimal absolute value of self:

BigDecimal('5').abs  # => 0.5e1
BigDecimal('-3').abs # => 0.3e1



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# File 'ext/bigdecimal/bigdecimal.c', line 2039

static VALUE
BigDecimal_abs(VALUE self)
{
    BDVALUE a = GetBDValueMust(self);
    BDVALUE c = NewZeroWrap(1, a.real->Prec * BASE_FIG);
    VpAsgn(c.real, a.real, 10);
    VpChangeSign(c.real, 1);
    RB_GC_GUARD(a.bigdecimal);
    return CheckGetValue(c);
}

#add(value, ndigits) ⇒ Object

Returns the BigDecimal sum of self and value with a precision of ndigits decimal digits.

When ndigits is less than the number of significant digits in the sum, the sum is rounded to that number of digits, according to the current rounding mode; see BigDecimal.mode.

Examples:

# Set the rounding mode.
BigDecimal.mode(BigDecimal::ROUND_MODE, :half_up)
b = BigDecimal('111111.111')
b.add(1, 0)               # => 0.111112111e6
b.add(1, 3)               # => 0.111e6
b.add(1, 6)               # => 0.111112e6
b.add(1, 15)              # => 0.111112111e6
b.add(1.0, 15)            # => 0.111112111e6
b.add(Rational(1, 1), 15) # => 0.111112111e6



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# File 'ext/bigdecimal/bigdecimal.c', line 1971

static VALUE
BigDecimal_add2(VALUE self, VALUE b, VALUE n)
{
    return BigDecimal_addsub_with_coerce(self, b, check_int_precision(n), +1);
}

#ceil(n) ⇒ Object

Return the smallest integer greater than or equal to the value, as a BigDecimal.

BigDecimal(‘3.14159’).ceil #=> 4 BigDecimal(‘-9.1’).ceil #=> -9

If n is specified and positive, the fractional part of the result has no more than that many digits.

If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.

BigDecimal(‘3.14159’).ceil(3) #=> 3.142 BigDecimal(‘13345.234’).ceil(-2) #=> 13400.0



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# File 'ext/bigdecimal/bigdecimal.c', line 2246

static VALUE
BigDecimal_ceil(int argc, VALUE *argv, VALUE self)
{
    return BigDecimal_truncate_floor_ceil(argc, argv, self, VP_ROUND_CEIL);
}

#clone ⇒ Object

:nodoc:



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# File 'ext/bigdecimal/bigdecimal.c', line 2530

static VALUE
BigDecimal_clone(VALUE self)
{
    return self;
}

#coerce(other) ⇒ Object

The coerce method provides support for Ruby type coercion. It is not enabled by default.

This means that binary operations like + * / or - can often be performed on a BigDecimal and an object of another type, if the other object can be coerced into a BigDecimal value.

e.g.

a = BigDecimal("1.0")
b = a / 2.0 #=> 0.5

Note that coercing a String to a BigDecimal is not supported by default; it requires a special compile-time option when building Ruby.



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# File 'ext/bigdecimal/bigdecimal.c', line 1234

static VALUE
BigDecimal_coerce(VALUE self, VALUE other)
{
    Real* pv = DATA_PTR(self);
    BDVALUE b = GetBDValueWithPrecMust(other, GetCoercePrec(pv, 0));
    return rb_assoc_new(CheckGetValue(b), self);
}

#div(*args) ⇒ Object

call-seq:

div(value)  -> integer
div(value, digits)  -> bigdecimal or integer

Divide by the specified value.

digits

If specified and less than the number of significant digits of the result, the result is rounded to that number of digits, according to BigDecimal.mode.

If digits is 0, the result is the same as for the / operator or #quo.

If digits is not specified, the result is an integer, by analogy with Float#div; see also BigDecimal#divmod.

See BigDecimal#/. See BigDecimal#quo.

Examples:

a = BigDecimal("4")
b = BigDecimal("3")

a.div(b, 3)  # => 0.133e1

a.div(b, 0)  # => 0.1333333333333333333e1
a / b        # => 0.1333333333333333333e1
a.quo(b)     # => 0.1333333333333333333e1

a.div(b)     # => 1



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# File 'ext/bigdecimal/bigdecimal.c', line 1936

static VALUE
BigDecimal_div3(int argc, VALUE *argv, VALUE self)
{
    VALUE b,n;

    rb_scan_args(argc, argv, "11", &b, &n);

    return BigDecimal_div2(self, b, n);
}

#divmod(value) ⇒ Object

Divides by the specified value, and returns the quotient and modulus as BigDecimal numbers. The quotient is rounded towards negative infinity.

For example:

require 'bigdecimal'

a = BigDecimal("42")
b = BigDecimal("9")

q, m = a.divmod(b)

c = q * b + m

a == c  #=> true

The quotient q is (a/b).floor, and the modulus is the amount that must be added to q * b to get a.



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# File 'ext/bigdecimal/bigdecimal.c', line 1833

static VALUE
BigDecimal_divmod(VALUE self, VALUE r)
{
    NULLABLE_BDVALUE div, mod;

    if (BigDecimal_DoDivmod(self, r, &div, &mod, false)) {
        return rb_assoc_new(BigDecimal_to_i(CheckGetValue(bdvalue_nonnullable(div))), CheckGetValue(bdvalue_nonnullable(mod)));
    }
    return DoSomeOne(self,r,rb_intern("divmod"));
}

#dup ⇒ Object

:nodoc:



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# File 'ext/bigdecimal/bigdecimal.c', line 2530

static VALUE
BigDecimal_clone(VALUE self)
{
    return self;
}

#eql?(r) ⇒ Boolean

Tests for value equality; returns true if the values are equal.

The == and === operators and the eql? method have the same implementation for BigDecimal.

Values may be coerced to perform the comparison:

BigDecimal('1.0') == 1.0  #=> true

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1456

static VALUE
BigDecimal_eq(VALUE self, VALUE r)
{
    return BigDecimalCmp(self, r, '=');
}

#exponent ⇒ Object

Returns the exponent of the BigDecimal number, as an Integer.

If the number can be represented as 0.xxxxxx*10**n where xxxxxx is a string of digits with no leading zeros, then n is the exponent.



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# File 'ext/bigdecimal/bigdecimal.c', line 2419

static VALUE
BigDecimal_exponent(VALUE self)
{
    ssize_t e = VpExponent10(GetSelfVpValue(self));
    return SSIZET2NUM(e);
}

#finite? ⇒ Boolean

Returns True if the value is finite (not NaN or infinite).

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1069

static VALUE
BigDecimal_IsFinite(VALUE self)
{
    Real *p = GetSelfVpValue(self);
    if (VpIsNaN(p)) return Qfalse;
    if (VpIsInf(p)) return Qfalse;
    return Qtrue;
}

#fix ⇒ Object

Return the integer part of the number, as a BigDecimal.



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# File 'ext/bigdecimal/bigdecimal.c', line 2052

static VALUE
BigDecimal_fix(VALUE self)
{
    BDVALUE a = GetBDValueMust(self);
    BDVALUE c = NewZeroWrap(1, (a.real->Prec + 1) * BASE_FIG);
    VpActiveRound(c.real, a.real, VP_ROUND_DOWN, 0); /* 0: round off */
    RB_GC_GUARD(a.bigdecimal);
    return CheckGetValue(c);
}

#floor(n) ⇒ Object

Return the largest integer less than or equal to the value, as a BigDecimal.

BigDecimal(‘3.14159’).floor #=> 3 BigDecimal(‘-9.1’).floor #=> -10

If n is specified and positive, the fractional part of the result has no more than that many digits.

If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.

BigDecimal(‘3.14159’).floor(3) #=> 3.141 BigDecimal(‘13345.234’).floor(-2) #=> 13300.0



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# File 'ext/bigdecimal/bigdecimal.c', line 2223

static VALUE
BigDecimal_floor(int argc, VALUE *argv, VALUE self)
{
    return BigDecimal_truncate_floor_ceil(argc, argv, self, VP_ROUND_FLOOR);
}

#frac ⇒ Object

Return the fractional part of the number, as a BigDecimal.



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# File 'ext/bigdecimal/bigdecimal.c', line 2196

static VALUE
BigDecimal_frac(VALUE self)
{
    BDVALUE a = GetBDValueMust(self);
    BDVALUE c = NewZeroWrap(1, (a.real->Prec + 1) * BASE_FIG);
    VpFrac(c.real, a.real);
    RB_GC_GUARD(a.bigdecimal);
    return CheckGetValue(c);
}

#hash ⇒ Integer

Returns the integer hash value for self.

Two instances of BigDecimal have the same hash value if and only if they have equal:

  • Sign.

  • Fractional part.

  • Exponent.

Returns:



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# File 'ext/bigdecimal/bigdecimal.c', line 640

static VALUE
BigDecimal_hash(VALUE self)
{
    BDVALUE v = GetBDValueMust(self);
    st_index_t hash = (st_index_t)v.real->sign;
    /* hash!=2: the case for 0(1),NaN(0) or +-Infinity(3) is sign itself */
    if(hash == 2 || hash == (st_index_t)-2) {
        hash ^= rb_memhash(v.real->frac, sizeof(DECDIG)*v.real->Prec);
        hash += v.real->exponent;
    }
    RB_GC_GUARD(v.bigdecimal);
    return ST2FIX(hash);
}

#infinite? ⇒ Boolean

Returns nil, -1, or 1 depending on whether the value is finite, -Infinity, or Infinity.

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1059

static VALUE
BigDecimal_IsInfinite(VALUE self)
{
    Real *p = GetSelfVpValue(self);
    if (VpIsPosInf(p)) return INT2FIX(1);
    if (VpIsNegInf(p)) return INT2FIX(-1);
    return Qnil;
}

#inspect ⇒ Object

Returns a string representation of self.

BigDecimal("1234.5678").inspect
  #=> "0.12345678e4"



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# File 'ext/bigdecimal/bigdecimal.c', line 2431

static VALUE
BigDecimal_inspect(VALUE self)
{
    BDVALUE v;
    volatile VALUE str;
    size_t nc;

    v = GetBDValueMust(self);
    nc = VpNumOfChars(v.real, "E");

    str = rb_str_new(0, nc);
    VpToString(v.real, RSTRING_PTR(str), RSTRING_LEN(str), 0, 0);
    rb_str_resize(str, strlen(RSTRING_PTR(str)));

    RB_GC_GUARD(v.bigdecimal);
    return str;
}

#modulo ⇒ Object

%: a%b = a - (a.to_f/b).floor * b



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# File 'ext/bigdecimal/bigdecimal.c', line 1782

static VALUE
BigDecimal_mod(VALUE self, VALUE r) /* %: a%b = a - (a.to_f/b).floor * b */
{
    NULLABLE_BDVALUE div, mod;

    if (BigDecimal_DoDivmod(self, r, &div, &mod, false)) {
        return CheckGetValue(bdvalue_nonnullable(mod));
    }
    return DoSomeOne(self, r, '%');
}

#mult(other, ndigits) ⇒ Object

Returns the BigDecimal product of self and value with a precision of ndigits decimal digits.

When ndigits is less than the number of significant digits in the sum, the sum is rounded to that number of digits, according to the current rounding mode; see BigDecimal.mode.

Examples:

# Set the rounding mode.
BigDecimal.mode(BigDecimal::ROUND_MODE, :half_up)
b = BigDecimal('555555.555')
b.mult(3, 0)              # => 0.1666666665e7
b.mult(3, 3)              # => 0.167e7
b.mult(3, 6)              # => 0.166667e7
b.mult(3, 15)             # => 0.1666666665e7
b.mult(3.0, 0)            # => 0.1666666665e7
b.mult(Rational(3, 1), 0) # => 0.1666666665e7
b.mult(Complex(3, 0), 0)  # => (0.1666666665e7+0.0i)



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# File 'ext/bigdecimal/bigdecimal.c', line 2022

static VALUE
BigDecimal_mult2(VALUE self, VALUE b, VALUE n)
{
    return BigDecimal_mult_with_coerce(self, b, check_int_precision(n));
}

#n_significant_digits ⇒ Integer

Returns the number of decimal significant digits in self.

BigDecimal("0").n_significant_digits         # => 0
BigDecimal("1").n_significant_digits         # => 1
BigDecimal("1.1").n_significant_digits       # => 2
BigDecimal("3.1415").n_significant_digits    # => 5
BigDecimal("-1e20").n_significant_digits     # => 1
BigDecimal("1e-20").n_significant_digits     # => 1
BigDecimal("Infinity").n_significant_digits  # => 0
BigDecimal("-Infinity").n_significant_digits # => 0
BigDecimal("NaN").n_significant_digits       # => 0

Returns:



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# File 'ext/bigdecimal/bigdecimal.c', line 602

static VALUE
BigDecimal_n_significant_digits(VALUE self)
{
    BDVALUE v = GetBDValueMust(self);
    if (VpIsZero(v.real) || !VpIsDef(v.real)) {
        return INT2FIX(0);
    }

    ssize_t n = v.real->Prec;  /* The length of frac without trailing zeros. */
    for (n = v.real->Prec; n > 0 && v.real->frac[n-1] == 0; --n);
    if (n == 0) return INT2FIX(0);

    DECDIG x;
    int nlz = BASE_FIG;
    for (x = v.real->frac[0]; x > 0; x /= 10) --nlz;

    int ntz = 0;
    for (x = v.real->frac[n-1]; x > 0 && x % 10 == 0; x /= 10) ++ntz;

    RB_GC_GUARD(v.bigdecimal);
    ssize_t n_significant_digits = BASE_FIG*n - nlz - ntz;
    return SSIZET2NUM(n_significant_digits);
}

#nan? ⇒ Boolean

Returns True if the value is Not a Number.

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1048

static VALUE
BigDecimal_IsNaN(VALUE self)
{
    Real *p = GetSelfVpValue(self);
    if (VpIsNaN(p))  return Qtrue;
    return Qfalse;
}

#nonzero? ⇒ Boolean

Returns self if the value is non-zero, nil otherwise.

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1430

static VALUE
BigDecimal_nonzero(VALUE self)
{
    Real *a = GetSelfVpValue(self);
    return VpIsZero(a) ? Qnil : self;
}

#power(y, prec = 0) ⇒ Object

call-seq:

power(n)
power(n, prec)

Returns the value raised to the power of n.

Also available as the operator **.



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# File 'lib/bigdecimal.rb', line 97

def power(y, prec = 0)
  prec = Internal.coerce_validate_prec(prec, :power, accept_zero: true)
  x = self
  y = Internal.coerce_to_bigdecimal(y, prec.nonzero? || n_significant_digits, :power)

  return Internal.nan_computation_result if x.nan? || y.nan?
  return BigDecimal(1) if y.zero?

  if y.infinite?
    if x < 0
      return BigDecimal(0) if x < -1 && y.negative?
      return BigDecimal(0) if x > -1 && y.positive?
      raise Math::DomainError, 'Result undefined for negative base raised to infinite power'
    elsif x < 1
      return y.positive? ? BigDecimal(0) : BigDecimal::Internal.infinity_computation_result
    elsif x == 1
      return BigDecimal(1)
    else
      return y.positive? ? BigDecimal::Internal.infinity_computation_result : BigDecimal(0)
    end
  end

  if x.infinite? && y < 0
    # Computation result will be +0 or -0. Avoid overflow.
    neg = x < 0 && y.frac.zero? && y % 2 == 1
    return neg ? -BigDecimal(0) : BigDecimal(0)
  end

  if x.zero?
    return BigDecimal(1) if y.zero?
    return BigDecimal(0) if y > 0
    if y.frac.zero? && y % 2 == 1 && x.sign == -1
      return -BigDecimal::Internal.infinity_computation_result
    else
      return BigDecimal::Internal.infinity_computation_result
    end
  elsif x < 0
    if y.frac.zero?
      if y % 2 == 0
        return (-x).power(y, prec)
      else
        return -(-x).power(y, prec)
      end
    else
      raise Math::DomainError, 'Computation results in complex number'
    end
  elsif x == 1
    return BigDecimal(1)
  end

  limit = BigDecimal.limit
  frac_part = y.frac

  if frac_part.zero? && prec.zero? && limit.zero?
    # Infinite precision calculation for `x ** int` and `x.power(int)`
    int_part = y.fix.to_i
    int_part = -int_part if (neg = int_part < 0)
    ans = BigDecimal(1)
    n = 1
    xn = x
    while true
      ans *= xn if int_part.allbits?(n)
      n <<= 1
      break if n > int_part
      xn *= xn
      # Detect overflow/underflow before consuming infinite memory
      if (xn.exponent.abs - 1) * int_part / n >= 0x7FFFFFFFFFFFFFFF
        return ((xn.exponent > 0) ^ neg ? BigDecimal::Internal.infinity_computation_result : BigDecimal(0)) * (int_part.even? || x > 0 ? 1 : -1)
      end
    end
    return neg ? BigDecimal(1) / ans : ans
  end

  result_prec = prec.nonzero? || [x.n_significant_digits, y.n_significant_digits, BigDecimal.double_fig].max + BigDecimal.double_fig
  result_prec = [result_prec, limit].min if prec.zero? && limit.nonzero?

  prec2 = result_prec + BigDecimal.double_fig

  if y < 0
    inv = x.power(-y, prec2)
    return BigDecimal(0) if inv.infinite?
    return BigDecimal::Internal.infinity_computation_result if inv.zero?
    return BigDecimal(1).div(inv, result_prec)
  end

  if frac_part.zero? && y.exponent < Math.log(result_prec) * 5 + 20
    # Use exponentiation by squaring if y is an integer and not too large
    pow_prec = prec2 + y.exponent
    n = 1
    xn = x
    ans = BigDecimal(1)
    int_part = y.fix.to_i
    while true
      ans = ans.mult(xn, pow_prec) if int_part.allbits?(n)
      n <<= 1
      break if n > int_part
      xn = xn.mult(xn, pow_prec)
    end
    ans.mult(1, result_prec)
  else
    if x > 1 && x.finite?
      # To calculate exp(z, prec), z needs prec+max(z.exponent, 0) precision if z > 0.
      # Estimate (y*log(x)).exponent
      logx_exponent = x < 2 ? (x - 1).exponent : Math.log10(x.exponent).round
      ylogx_exponent = y.exponent + logx_exponent
      prec2 += [ylogx_exponent, 0].max
    end
    BigMath.exp(BigMath.log(x, prec2).mult(y, prec2), result_prec)
  end
end

#precision ⇒ Integer

Returns the number of decimal digits in self:

BigDecimal("0").precision         # => 0
BigDecimal("1").precision         # => 1
BigDecimal("1.1").precision       # => 2
BigDecimal("3.1415").precision    # => 5
BigDecimal("-1e20").precision     # => 21
BigDecimal("1e-20").precision     # => 20
BigDecimal("Infinity").precision  # => 0
BigDecimal("-Infinity").precision # => 0
BigDecimal("NaN").precision       # => 0

Returns:



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# File 'ext/bigdecimal/bigdecimal.c', line 536

static VALUE
BigDecimal_precision(VALUE self)
{
    ssize_t precision;
    BigDecimal_count_precision_and_scale(self, &precision, NULL);
    return SSIZET2NUM(precision);
}

#precision_scale ⇒ Array

Returns a 2-length array; the first item is the result of BigDecimal#precision and the second one is of BigDecimal#scale.

See BigDecimal#precision. See BigDecimal#scale.

Returns:

  • (Array) 


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# File 'ext/bigdecimal/bigdecimal.c', line 578

static VALUE
BigDecimal_precision_scale(VALUE self)
{
    ssize_t precision, scale;
    BigDecimal_count_precision_and_scale(self, &precision, &scale);
    return rb_assoc_new(SSIZET2NUM(precision), SSIZET2NUM(scale));
}

#quo(value) ⇒ Object #quo(value, digits) ⇒ Object

Divide by the specified value.

digits

If specified and less than the number of significant digits of the result, the result is rounded to the given number of digits, according to the rounding mode indicated by BigDecimal.mode.

If digits is 0 or omitted, the result is the same as for the / operator.

See BigDecimal#/. See BigDecimal#div.



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# File 'ext/bigdecimal/bigdecimal.c', line 1644

static VALUE
BigDecimal_quo(int argc, VALUE *argv, VALUE self)
{
    VALUE value, digits, result;
    SIGNED_VALUE n = -1;

    argc = rb_scan_args(argc, argv, "11", &value, &digits);
    if (argc > 1) {
        n = check_int_precision(digits);
    }

    if (n > 0) {
        result = BigDecimal_div2(self, value, digits);
    }
    else {
        result = BigDecimal_div(self, value);
    }

    return result;
}

#remainder ⇒ Object

remainder



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# File 'ext/bigdecimal/bigdecimal.c', line 1800

static VALUE
BigDecimal_remainder(VALUE self, VALUE r) /* remainder */
{
    NULLABLE_BDVALUE div, mod = { Qnil, NULL };

    if (BigDecimal_DoDivmod(self, r, &div, &mod, true)) {
        return CheckGetValue(bdvalue_nonnullable(mod));
    }
    return DoSomeOne(self, r, rb_intern("remainder"));
}

#round(n, mode) ⇒ Object

Round to the nearest integer (by default), returning the result as a BigDecimal if n is specified and positive, or as an Integer if it isn’t.

BigDecimal(‘3.14159’).round #=> 3 BigDecimal(‘8.7’).round #=> 9 BigDecimal(‘-9.9’).round #=> -10

BigDecimal(‘3.14159’).round(2).class.name #=> “BigDecimal” BigDecimal(‘3.14159’).round.class.name #=> “Integer” BigDecimal(‘3.14159’).round(0).class.name #=> “Integer”

If n is specified and positive, the fractional part of the result has no more than that many digits.

If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result, and return value will be an Integer.

BigDecimal(‘3.14159’).round(3) #=> 3.142 BigDecimal(‘13345.234’).round(-2) #=> 13300

The value of the optional mode argument can be used to determine how rounding is performed; see BigDecimal.mode.



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# File 'ext/bigdecimal/bigdecimal.c', line 2088

static VALUE
BigDecimal_round(int argc, VALUE *argv, VALUE self)
{
    BDVALUE c, a;
    int    iLoc = 0;
    VALUE  vLoc;
    VALUE  vRound;
    int    round_to_int = 0;
    size_t mx;

    unsigned short sw = VpGetRoundMode();

    switch (rb_scan_args(argc, argv, "02", &vLoc, &vRound)) {
      case 0:
	iLoc = 0;
        round_to_int = 1;
	break;
      case 1:
        if (RB_TYPE_P(vLoc, T_HASH)) {
	    sw = check_rounding_mode_option(vLoc);
	}
	else {
	    iLoc = NUM2INT(vLoc);
            if (iLoc < 1) round_to_int = 1;
	}
	break;
      case 2:
	iLoc = NUM2INT(vLoc);
	if (RB_TYPE_P(vRound, T_HASH)) {
	    sw = check_rounding_mode_option(vRound);
	}
	else {
	    sw = check_rounding_mode(vRound);
	}
	break;
      default:
	break;
    }

    a = GetBDValueMust(self);
    mx = (a.real->Prec + 1) * BASE_FIG;
    c = NewZeroWrap(1, mx);

    VpActiveRound(c.real, a.real, sw, iLoc);

    RB_GC_GUARD(a.bigdecimal);

    if (round_to_int) {
        return BigDecimal_to_i(CheckGetValue(c));
    }
    return CheckGetValue(c);
}

#scale ⇒ Integer

Returns the number of decimal digits following the decimal digits in self.

BigDecimal("0").scale         # => 0
BigDecimal("1").scale         # => 0
BigDecimal("1.1").scale       # => 1
BigDecimal("3.1415").scale    # => 4
BigDecimal("-1e20").scale     # => 0
BigDecimal("1e-20").scale     # => 20
BigDecimal("Infinity").scale  # => 0
BigDecimal("-Infinity").scale # => 0
BigDecimal("NaN").scale       # => 0

Returns:



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# File 'ext/bigdecimal/bigdecimal.c', line 560

static VALUE
BigDecimal_scale(VALUE self)
{
    ssize_t scale;
    BigDecimal_count_precision_and_scale(self, NULL, &scale);
    return SSIZET2NUM(scale);
}

#sign ⇒ Object

Returns the sign of the value.

Returns a positive value if > 0, a negative value if < 0. It behaves the same with zeros - it returns a positive value for a positive zero (BigDecimal(‘0’)) and a negative value for a negative zero (BigDecimal(‘-0’)).

The specific value returned indicates the type and sign of the BigDecimal, as follows:

BigDecimal::SIGN_NaN

value is Not a Number

BigDecimal::SIGN_POSITIVE_ZERO

value is +0

BigDecimal::SIGN_NEGATIVE_ZERO

value is -0

BigDecimal::SIGN_POSITIVE_INFINITE

value is +Infinity

BigDecimal::SIGN_NEGATIVE_INFINITE

value is -Infinity

BigDecimal::SIGN_POSITIVE_FINITE

value is positive

BigDecimal::SIGN_NEGATIVE_FINITE

value is negative



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# File 'ext/bigdecimal/bigdecimal.c', line 3090

static VALUE
BigDecimal_sign(VALUE self)
{ /* sign */
    int s = GetSelfVpValue(self)->sign;
    return INT2FIX(s);
}

#split ⇒ Object

Splits a BigDecimal number into four parts, returned as an array of values.

The first value represents the sign of the BigDecimal, and is -1 or 1, or 0 if the BigDecimal is Not a Number.

The second value is a string representing the significant digits of the BigDecimal, with no leading zeros.

The third value is the base used for arithmetic (currently always 10) as an Integer.

The fourth value is an Integer exponent.

If the BigDecimal can be represented as 0.xxxxxx*10**n, then xxxxxx is the string of significant digits with no leading zeros, and n is the exponent.

From these values, you can translate a BigDecimal to a float as follows:

sign, significant_digits, base, exponent = a.split
f = sign * "0.#{significant_digits}".to_f * (base ** exponent)

(Note that the to_f method is provided as a more convenient way to translate a BigDecimal to a Float.)



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# File 'ext/bigdecimal/bigdecimal.c', line 2381

static VALUE
BigDecimal_split(VALUE self)
{
    BDVALUE v;
    VALUE obj,str;
    ssize_t e, s;
    char *psz1;

    v = GetBDValueMust(self);
    str = rb_str_new(0, VpNumOfChars(v.real, "E"));
    psz1 = RSTRING_PTR(str);
    VpSzMantissa(v.real, psz1, RSTRING_LEN(str));
    s = 1;
    if(psz1[0] == '-') {
	size_t len = strlen(psz1 + 1);

	memmove(psz1, psz1 + 1, len);
	psz1[len] = '\0';
        s = -1;
    }
    if (psz1[0] == 'N') s = 0; /* NaN */
    e = VpExponent10(v.real);
    obj = rb_ary_new2(4);
    rb_ary_push(obj, INT2FIX(s));
    rb_ary_push(obj, str);
    rb_str_resize(str, strlen(psz1));
    rb_ary_push(obj, INT2FIX(10));
    rb_ary_push(obj, SSIZET2NUM(e));

    RB_GC_GUARD(v.bigdecimal);
    return obj;
}

#sqrt(prec) ⇒ Object

Returns the square root of the value.

Result has at least prec significant digits.

Raises:

  • (FloatDomainError) 


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# File 'lib/bigdecimal.rb', line 212

def sqrt(prec)
  prec = Internal.coerce_validate_prec(prec, :sqrt, accept_zero: true)
  return Internal.infinity_computation_result if infinite? == 1

  raise FloatDomainError, 'sqrt of negative value' if self < 0
  raise FloatDomainError, "sqrt of 'NaN'(Not a Number)" if nan?
  return self if zero?

  if prec == 0
    limit = BigDecimal.limit
    prec = n_significant_digits + BigDecimal.double_fig
    prec = [limit, prec].min if limit.nonzero?
  end

  ex = exponent / 2
  x = _decimal_shift(-2 * ex)
  y = BigDecimal(Math.sqrt(x.to_f), 0)
  precs = [prec + BigDecimal.double_fig]
  precs << 2 + precs.last / 2 while precs.last > BigDecimal.double_fig
  precs.reverse_each do |p|
    y = y.add(x.div(y, p), p).div(2, p)
  end
  y._decimal_shift(ex).mult(1, prec)
end

#sub(value, digits) ⇒ Object

Subtract the specified value.

e.g.

c = a.sub(b,n)
digits

If specified and less than the number of significant digits of the result, the result is rounded to that number of digits, according to BigDecimal.mode.



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# File 'ext/bigdecimal/bigdecimal.c', line 1990

static VALUE
BigDecimal_sub2(VALUE self, VALUE b, VALUE n)
{
    return BigDecimal_addsub_with_coerce(self, b, check_int_precision(n), -1);
}

#to_d ⇒ Object

call-seq:

a.to_d -> bigdecimal

Returns self.

require 'bigdecimal/util'

d = BigDecimal("3.14")
d.to_d                       # => 0.314e1



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# File 'lib/bigdecimal/util.rb', line 110

def to_d
  self
end

#to_digits ⇒ Object

call-seq:

a.to_digits -> string

Converts a BigDecimal to a String of the form “nnnnnn.mmm”. This method is deprecated; use BigDecimal#to_s(“F”) instead.

require 'bigdecimal/util'

d = BigDecimal("3.14")
d.to_digits                  # => "3.14"



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# File 'lib/bigdecimal/util.rb', line 90

def to_digits
  if self.nan? || self.infinite? || self.zero?
    self.to_s
  else
    i       = self.to_i.to_s
    _,f,_,z = self.frac.split
    i + "." + ("0"*(-z)) + f
  end
end

#to_f ⇒ Object

Returns a new Float object having approximately the same value as the BigDecimal number. Normal accuracy limits and built-in errors of binary Float arithmetic apply.



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# File 'ext/bigdecimal/bigdecimal.c', line 1130

static VALUE
BigDecimal_to_f(VALUE self)
{
    double d;
    SIGNED_VALUE e;
    char *buf;
    volatile VALUE str;
    BDVALUE v = GetBDValueMust(self);
    bool negative = BIGDECIMAL_NEGATIVE_P(v.real);

    if (VpVtoD(&d, &e, v.real) != 1)
	return rb_float_new(d);
    if (e > (SIGNED_VALUE)(DBL_MAX_10_EXP+BASE_FIG))
	goto overflow;
    if (e < (SIGNED_VALUE)(DBL_MIN_10_EXP-DBL_DIG))
	goto underflow;

    str = rb_str_new(0, VpNumOfChars(v.real, "E"));
    buf = RSTRING_PTR(str);
    VpToString(v.real, buf, RSTRING_LEN(str), 0, 0);

    RB_GC_GUARD(v.bigdecimal);

    errno = 0;
    d = strtod(buf, 0);
    if (errno == ERANGE) {
	if (d == 0.0) goto underflow;
	if (fabs(d) >= HUGE_VAL) goto overflow;
    }
    return rb_float_new(d);

overflow:
    VpException(VP_EXCEPTION_OVERFLOW, "BigDecimal to Float conversion", 0);
    if (negative)
	return rb_float_new(VpGetDoubleNegInf());
    else
	return rb_float_new(VpGetDoublePosInf());

underflow:
    VpException(VP_EXCEPTION_UNDERFLOW, "BigDecimal to Float conversion", 0);
    if (negative)
	return rb_float_new(-0.0);
    else
	return rb_float_new(0.0);
}

#to_i ⇒ Object

Returns the value as an Integer.

If the BigDecimal is infinity or NaN, raises FloatDomainError.



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# File 'ext/bigdecimal/bigdecimal.c', line 1091

static VALUE
BigDecimal_to_i(VALUE self)
{
    BDVALUE v;
    VALUE ret;

    v = GetBDValueMust(self);
    BigDecimal_check_num(v.real);

    if (v.real->exponent <= 0) return INT2FIX(0);
    if (v.real->exponent == 1) {
        ret = LONG2NUM((long)(VpGetSign(v.real) * (DECDIG_DBL_SIGNED)v.real->frac[0]));
    }
    else {
        VALUE fix = (ssize_t)v.real->Prec > v.real->exponent ? BigDecimal_fix(self) : self;
        VALUE digits = RARRAY_AREF(BigDecimal_split(fix), 1);
        ssize_t dpower = VpExponent10(v.real) - (ssize_t)RSTRING_LEN(digits);
        ret = rb_funcall(digits, rb_intern("to_i"), 0);

        if (BIGDECIMAL_NEGATIVE_P(v.real)) {
            ret = rb_funcall(ret, '*', 1, INT2FIX(-1));
        }
        if (dpower) {
            VALUE pow10 = rb_funcall(INT2FIX(10), rb_intern("**"), 1, SSIZET2NUM(dpower));
            // In Ruby < 3.4, int**int may return Float::INFINITY
            if (RB_TYPE_P(pow10, T_FLOAT)) rb_raise(rb_eFloatDomainError, "Infinity");

            ret = rb_funcall(ret, '*', 1, pow10);
        }
    }

    RB_GC_GUARD(v.bigdecimal);
    return ret;
}

#to_int ⇒ Object

Returns the value as an Integer.

If the BigDecimal is infinity or NaN, raises FloatDomainError.



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# File 'ext/bigdecimal/bigdecimal.c', line 1091

static VALUE
BigDecimal_to_i(VALUE self)
{
    BDVALUE v;
    VALUE ret;

    v = GetBDValueMust(self);
    BigDecimal_check_num(v.real);

    if (v.real->exponent <= 0) return INT2FIX(0);
    if (v.real->exponent == 1) {
        ret = LONG2NUM((long)(VpGetSign(v.real) * (DECDIG_DBL_SIGNED)v.real->frac[0]));
    }
    else {
        VALUE fix = (ssize_t)v.real->Prec > v.real->exponent ? BigDecimal_fix(self) : self;
        VALUE digits = RARRAY_AREF(BigDecimal_split(fix), 1);
        ssize_t dpower = VpExponent10(v.real) - (ssize_t)RSTRING_LEN(digits);
        ret = rb_funcall(digits, rb_intern("to_i"), 0);

        if (BIGDECIMAL_NEGATIVE_P(v.real)) {
            ret = rb_funcall(ret, '*', 1, INT2FIX(-1));
        }
        if (dpower) {
            VALUE pow10 = rb_funcall(INT2FIX(10), rb_intern("**"), 1, SSIZET2NUM(dpower));
            // In Ruby < 3.4, int**int may return Float::INFINITY
            if (RB_TYPE_P(pow10, T_FLOAT)) rb_raise(rb_eFloatDomainError, "Infinity");

            ret = rb_funcall(ret, '*', 1, pow10);
        }
    }

    RB_GC_GUARD(v.bigdecimal);
    return ret;
}

#to_r ⇒ Object

Converts a BigDecimal to a Rational.



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# File 'ext/bigdecimal/bigdecimal.c', line 1179

static VALUE
BigDecimal_to_r(VALUE self)
{
    BDVALUE v;
    ssize_t sign, power, denomi_power;
    VALUE a, digits, numerator;

    v = GetBDValueMust(self);
    BigDecimal_check_num(v.real);
    sign = VpGetSign(v.real);
    power = VpExponent10(v.real);
    RB_GC_GUARD(v.bigdecimal);

    a = BigDecimal_split(self);
    digits = RARRAY_AREF(a, 1);
    denomi_power = power - RSTRING_LEN(digits);
    numerator = rb_funcall(digits, rb_intern("to_i"), 0);

    if (sign < 0) {
	numerator = rb_funcall(numerator, '*', 1, INT2FIX(-1));
    }
    if (denomi_power < 0) {
	return rb_Rational(numerator,
			   rb_funcall(INT2FIX(10), rb_intern("**"), 1,
				      INT2FIX(-denomi_power)));
    }
    else {
	return rb_Rational1(rb_funcall(numerator, '*', 1,
				       rb_funcall(INT2FIX(10), rb_intern("**"), 1,
						  INT2FIX(denomi_power))));
    }
}

#to_s(s) ⇒ Object

Converts the value to a string.

The default format looks like 0.xxxxEnn.

The optional parameter s consists of either an integer; or an optional ‘+’ or ‘ ’, followed by an optional number, followed by an optional ‘E’ or ‘F’.

If there is a ‘+’ at the start of s, positive values are returned with a leading ‘+’.

A space at the start of s returns positive values with a leading space.

If s contains a number, a space is inserted after each group of that many digits, starting from ‘.’ and counting outwards.

If s ends with an ‘E’, scientific notation (0.xxxxEnn) is used.

If s ends with an ‘F’, conventional floating point notation is used.

Examples:

BigDecimal('-1234567890123.45678901234567890').to_s('5F')
  #=> '-123 45678 90123.45678 90123 45678 9'

BigDecimal('1234567890123.45678901234567890').to_s('+8F')
  #=> '+12345 67890123.45678901 23456789'

BigDecimal('1234567890123.45678901234567890').to_s(' F')
  #=> ' 1234567890123.4567890123456789'



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# File 'ext/bigdecimal/bigdecimal.c', line 2285

static VALUE
BigDecimal_to_s(int argc, VALUE *argv, VALUE self)
{
    int   fmt = 0;   /* 0: E format, 1: F format */
    int   fPlus = 0; /* 0: default, 1: set ' ' before digits, 2: set '+' before digits. */
    BDVALUE v;
    volatile VALUE str;
    char  *psz;
    char   ch;
    size_t nc, mc = 0;
    SIGNED_VALUE m;
    VALUE  f;

    v = GetBDValueMust(self);

    if (rb_scan_args(argc, argv, "01", &f) == 1) {
	if (RB_TYPE_P(f, T_STRING)) {
	    psz = StringValueCStr(f);
	    if (*psz == ' ') {
		fPlus = 1;
		psz++;
	    }
	    else if (*psz == '+') {
		fPlus = 2;
		psz++;
	    }
	    while ((ch = *psz++) != 0) {
		if (ISSPACE(ch)) {
		    continue;
		}
		if (!ISDIGIT(ch)) {
		    if (ch == 'F' || ch == 'f') {
			fmt = 1; /* F format */
		    }
		    break;
		}
		mc = mc*10 + ch - '0';
	    }
	}
	else {
	    m = NUM2INT(f);
	    if (m <= 0) {
		rb_raise(rb_eArgError, "argument must be positive");
	    }
	    mc = (size_t)m;
	}
    }
    if (fmt) {
	nc = VpNumOfChars(v.real, "F");
    }
    else {
	nc = VpNumOfChars(v.real, "E");
    }
    if (mc > 0) {
	nc += (nc + mc - 1) / mc + 1;
    }

    str = rb_usascii_str_new(0, nc);
    psz = RSTRING_PTR(str);

    if (fmt) {
	VpToFString(v.real, psz, RSTRING_LEN(str), mc, fPlus);
    }
    else {
	VpToString (v.real, psz, RSTRING_LEN(str), mc, fPlus);
    }
    rb_str_resize(str, strlen(psz));

    RB_GC_GUARD(v.bigdecimal);
    return str;
}

#truncate(n) ⇒ Object

Truncate to the nearest integer (by default), returning the result as a BigDecimal.

BigDecimal(‘3.14159’).truncate #=> 3 BigDecimal(‘8.7’).truncate #=> 8 BigDecimal(‘-9.9’).truncate #=> -9

If n is specified and positive, the fractional part of the result has no more than that many digits.

If n is specified and negative, at least that many digits to the left of the decimal point will be 0 in the result.

BigDecimal(‘3.14159’).truncate(3) #=> 3.141 BigDecimal(‘13345.234’).truncate(-2) #=> 13300.0



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# File 'ext/bigdecimal/bigdecimal.c', line 2188

static VALUE
BigDecimal_truncate(int argc, VALUE *argv, VALUE self)
{
    return BigDecimal_truncate_floor_ceil(argc, argv, self, VP_ROUND_DOWN);
}

#vpdivd(r, cprec) ⇒ Object 



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# File 'ext/bigdecimal/bigdecimal.c', line 3228

VALUE
BigDecimal_vpdivd(VALUE self, VALUE r, VALUE cprec) {
    BDVALUE a,b,c,d;
    size_t cn = NUM2INT(cprec);
    a = GetBDValueMust(self);
    b = GetBDValueMust(r);
    c = NewZeroWrap(1, cn * BASE_FIG);
    d = NewZeroWrap(1, VPDIVD_REM_PREC(a.real, b.real, c.real) * BASE_FIG);
    VpDivd(c.real, d.real, a.real, b.real);
    RB_GC_GUARD(a.bigdecimal);
    RB_GC_GUARD(b.bigdecimal);
    return rb_assoc_new(c.bigdecimal, d.bigdecimal);
}

#vpmult(v) ⇒ Object 



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# File 'ext/bigdecimal/bigdecimal.c', line 3242

VALUE
BigDecimal_vpmult(VALUE self, VALUE v) {
    BDVALUE a,b,c;
    a = GetBDValueMust(self);
    b = GetBDValueMust(v);
    c = NewZeroWrap(1, VPMULT_RESULT_PREC(a.real, b.real) * BASE_FIG);
    VpMult(c.real, a.real, b.real);
    RB_GC_GUARD(a.bigdecimal);
    RB_GC_GUARD(b.bigdecimal);
    return c.bigdecimal;
}

#zero? ⇒ Boolean

Returns True if the value is zero.

Returns:

  • (Boolean) 


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# File 'ext/bigdecimal/bigdecimal.c', line 1422

static VALUE
BigDecimal_zero(VALUE self)
{
    Real *a = GetSelfVpValue(self);
    return VpIsZero(a) ? Qtrue : Qfalse;
}