Method: Math#log

Defined in:
math.c

#log(x) ⇒ Float (private) #log(x, base) ⇒ Float (private)

Returns the logarithm of x. If additional second argument is given, it will be the base of logarithm. Otherwise it is e (for the natural logarithm).

Domain: (0, INFINITY)

Codomain: (-INFINITY, INFINITY)

Math.log(0)          #=> -Infinity
Math.log(1)          #=> 0.0
Math.log(Math::E)    #=> 1.0
Math.log(Math::E**3) #=> 3.0
Math.log(12, 3)      #=> 2.2618595071429146

Overloads:



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# File 'math.c', line 434

static VALUE
math_log(int argc, const VALUE *argv, VALUE obj)
{
    VALUE x, base;
    double d;

    rb_scan_args(argc, argv, "11", &x, &base);
    d = math_log1(x);
    if (argc == 2) {
  d /= math_log1(base);
    }
    return DBL2NUM(d);
}