Module: Nio::BurgerDybvig
- Defined in:
- lib/nio/fmt.rb
Overview
:nodoc: all
Class Method Summary collapse
- .exptt(_B, k) ⇒ Object
- .fixup(r, s, m_p, m_m, k, _B, low_ok, high_ok) ⇒ Object
- .float_to_digits(v, f, e, round_mode, min_e, p, b, _B) ⇒ Object
- .float_to_digits_max(v, f, e, round_mode, min_e, p, b, _B) ⇒ Object
- .generate(r, s, m_p, m_m, _B, low_ok, high_ok) ⇒ Object
- .generate_max(r, s, m_p, m_m, _B, low_ok, high_ok) ⇒ Object
- .logB(_B, x) ⇒ Object
- .scale(r, s, m_p, m_m, k, _B, low_ok, high_ok, v) ⇒ Object
- .scale2(r, s, m_p, m_m, k, _B, low_ok, high_ok) ⇒ Object
Class Method Details
.exptt(_B, k) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1459 def exptt(_B, k) if _B==10 && k>=0 && k<326 $exptt_table[k] else _B**k end end |
.fixup(r, s, m_p, m_m, k, _B, low_ok, high_ok) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1397 def fixup(r,s,m_p,m_m,k,_B,low_ok,high_ok) if (high_ok ? (r+m_p >= s) : (r+m_p > s)) # too low? [r,s*_B,m_p,m_m,k+1] else [r,s,m_p,m_m,k] end end |
.float_to_digits(v, f, e, round_mode, min_e, p, b, _B) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1348 def float_to_digits(v,f,e,round_mode,min_e,p,b,_B) case round_mode when :even roundl = roundh = f.even? when :inf roundl = true roundh = false when :zero roundl = false roundh = true else # here we don't assume any rounding in the floating point numbers # the result is valid for any rounding but may produce more digits # than stricly necessary for specifica rounding modes. roundl = false roundh = false end if e >= 0 if f != exptt(b,p-1) be = exptt(b,e) r,s,m_p,m_m,k = scale(f*be*2,2,be,be,0,_B,roundl ,roundh,v) else be = exptt(b,e) be1 = be*b r,s,m_p,m_m,k = scale(f*be1*2,b*2,be1,be,0,_B,roundl ,roundh,v) end else if e==min_e or f != exptt(b,p-1) r,s,m_p,m_m,k = scale(f*2,exptt(b,-e)*2,1,1,0,_B,roundl ,roundh,v) else r,s,m_p,m_m,k = scale(f*b*2,exptt(b,1-e)*2,b,1,0,_B,roundl ,roundh,v) end end [k]+generate(r,s,m_p,m_m,_B,roundl ,roundh) end |
.float_to_digits_max(v, f, e, round_mode, min_e, p, b, _B) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1477 def float_to_digits_max(v,f,e,round_mode,min_e,p,b,_B) case round_mode when :even roundl = roundh = f.even? when :inf roundl = true roundh = false when :zero roundl = false roundh = true else # here we don't assume any rounding in the floating point numbers # the result is valid for any rounding but may produce more digits # than stricly necessary for specifica rounding modes. roundl = false roundh = false end if e >= 0 if f != exptt(b,p-1) be = exptt(b,e) r,s,m_p,m_m,k = scale(f*be*2,2,be,be,0,_B,roundl ,roundh,v) else be = exptt(b,e) be1 = be*b r,s,m_p,m_m,k = scale(f*be1*2,b*2,be1,be,0,_B,roundl ,roundh,v) end else if e==min_e or f != exptt(b,p-1) r,s,m_p,m_m,k = scale(f*2,exptt(b,-e)*2,1,1,0,_B,roundl ,roundh,v) else r,s,m_p,m_m,k = scale(f*b*2,exptt(b,1-e)*2,b,1,0,_B,roundl ,roundh,v) end end [k]+generate_max(r,s,m_p,m_m,_B,roundl ,roundh) end |
.generate(r, s, m_p, m_m, _B, low_ok, high_ok) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1422 def generate(r,s,m_p,m_m,_B,low_ok ,high_ok) list = [] loop do d,r = (r*_B).divmod(s) m_p *= _B m_m *= _B tc1 = low_ok ? (r<=m_m) : (r<m_m) tc2 = high_ok ? (r+m_p >= s) : (r+m_p > s) if not tc1 if not tc2 list << d else list << d+1 break end else if not tc2 list << d break else if r*2 < s list << d break else list << d+1 break end end end end list end |
.generate_max(r, s, m_p, m_m, _B, low_ok, high_ok) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1515 def generate_max(r,s,m_p,m_m,_B,low_ok ,high_ok) list = [false] loop do d,r = (r*_B).divmod(s) m_p *= _B m_m *= _B list << d tc1 = low_ok ? (r<=m_m) : (r<m_m) tc2 = high_ok ? (r+m_p >= s) : (r+m_p > s) if tc1 && tc2 list[0] = true if r*2 >= s break end end list end |
.logB(_B, x) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1469 def logB(_B, x) if _B>=2 && _B<37 Math.log(x)*$logB_table[_B] else Math.log(x)/Math.log(_B) end end |
.scale(r, s, m_p, m_m, k, _B, low_ok, high_ok, v) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1386 def scale(r,s,m_p,m_m,k,_B,low_ok ,high_ok,v) return scale2(r,s,m_p,m_m,k,_B,low_ok ,high_ok) if v==0 est = (logB(_B,v)-1E-10).ceil.to_i if est>=0 fixup(r,s*exptt(_B,est),m_p,m_m,est,_B,low_ok,high_ok) else sc = exptt(_B,-est) fixup(r*sc,s,m_p*sc,m_m*sc,est,_B,low_ok,high_ok) end end |
.scale2(r, s, m_p, m_m, k, _B, low_ok, high_ok) ⇒ Object
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# File 'lib/nio/fmt.rb', line 1405 def scale2(r,s,m_p,m_m,k,_B,low_ok ,high_ok) loop do if (high_ok ? (r+m_p >= s) : (r+m_p > s)) # k is too low s *= _B k += 1 elsif (high_ok ? ((r+m_p)*_B<s) : ((r+m_p)*_B<=s)) # k is too high r *= _B m_p *= _B m_m *= _B k -= 1 else break end end [r,s,m_p,m_m,k] end |