bigdecimal_snippets.rb

# size_t 32bit
# docker run  -v `pwd`:/bigdecimal --rm -ti arm32v7/ruby bash

# unused defs
code = File.read('ext/bigdecimal/bigdecimal.c')
header = File.read('ext/bigdecimal/bigdecimal.h')
defs = code.scan(/#define ([a-zA-Z_0-9]+)/).uniq
hdefs = header.scan(/#define ([a-zA-Z_0-9]+)/).uniq
defs |= hdefs.select{header.scan(/[a-zA-Z_0-9]+/).count(it[0])==1}
pp defs.map{[it[0], code.scan(/[a-zA-Z_0-9]+/).count(it[0])]}.sort_by(&:last)

# divmod consisntency
require 'bigdecimal'
ns = [*1..100]
es = [*-100..100]
n=0
loop do
  n+=1
  p n if n%100000==0
  xn=ns.sample
  yn=ns.sample
  xe=es.sample
  ye=es.sample
  c1 = rand(10).to_s
  c2 = rand(10).to_s
  c3 = rand(10).to_s
  c4 = rand(10).to_s
  x = BigDecimal('3.' + c1 * xn + c2 + "E#{xe}")
  y = BigDecimal(['1.', '-1.'].sample + c3 * yn + c4 + "E#{ye}")
  d,m = x.divmod(y)
  (p [x,y,d,m,x-d*y];break) unless x == d * y + m && d.frac.zero? && (y>0 ? 0 <= m && m < y : y < m && m <= 0)
end

# example test
File.read('lib/bigdecimal/math.rb').scan(/^[# ]+BigMath.+\n.+=> *".+"/).each{|s|
  code = s[/BigMath.+/]; a=eval(s[/".+"/])
  puts code
  y=eval(code);puts y==a ? 'OK' : [:error, y, a]
}

# precision test
d1 = BigDecimal('1e-100')
d2 = d1 * BigDecimal(2).sqrt(200)
%i[cbrt sin cos tan asin acos atan sinh cosh tanh asinh acosh atanh log2 log10 exp log].each do |m|
  next unless BigMath.respond_to?(m)
  p m
  [-1, 0, 0.5, 1, 2, 10, 100].each do |x0|
    [d1, d2, 0, -d1, -d2].each do |d|
      x = BigDecimal(x0, 0) + d
      vt = BigMath.send(m, x, 400)
      v = BigMath.send(m, x, 300)
      binding.irb unless (v/vt-1).exponent < 310
    rescue Math::DomainError
    end
  end
end