diff options
Diffstat (limited to 'ruby_1_9_3/ext/bigdecimal/lib/bigdecimal/math.rb')
| -rw-r--r-- | ruby_1_9_3/ext/bigdecimal/lib/bigdecimal/math.rb | 206 |
1 files changed, 0 insertions, 206 deletions
diff --git a/ruby_1_9_3/ext/bigdecimal/lib/bigdecimal/math.rb b/ruby_1_9_3/ext/bigdecimal/lib/bigdecimal/math.rb deleted file mode 100644 index 03c59bfccb..0000000000 --- a/ruby_1_9_3/ext/bigdecimal/lib/bigdecimal/math.rb +++ /dev/null @@ -1,206 +0,0 @@ -require 'bigdecimal' - -# -#-- -# Contents: -# sqrt(x, prec) -# sin (x, prec) -# cos (x, prec) -# atan(x, prec) Note: |x|<1, x=0.9999 may not converge. -# log (x, prec) -# PI (prec) -# E (prec) == exp(1.0,prec) -# -# where: -# x ... BigDecimal number to be computed. -# |x| must be small enough to get convergence. -# prec ... Number of digits to be obtained. -#++ -# -# Provides mathematical functions. -# -# Example: -# -# require "bigdecimal" -# require "bigdecimal/math" -# -# include BigMath -# -# a = BigDecimal((PI(100)/2).to_s) -# puts sin(a,100) # -> 0.10000000000000000000......E1 -# -module BigMath - module_function - - # Computes the square root of x to the specified number of digits of - # precision. - # - # BigDecimal.new('2').sqrt(16).to_s - # -> "0.14142135623730950488016887242096975E1" - # - def sqrt(x,prec) - x.sqrt(prec) - end - - # Computes the sine of x to the specified number of digits of precision. - # - # If x is infinite or NaN, returns NaN. - def sin(x, prec) - raise ArgumentError, "Zero or negative precision for sin" if prec <= 0 - return BigDecimal("NaN") if x.infinite? || x.nan? - n = prec + BigDecimal.double_fig - one = BigDecimal("1") - two = BigDecimal("2") - x = -x if neg = x < 0 - if x > (twopi = two * BigMath.PI(prec)) - if x > 30 - x %= twopi - else - x -= twopi while x > twopi - end - end - x1 = x - x2 = x.mult(x,n) - sign = 1 - y = x - d = y - i = one - z = one - while d.nonzero? && ((m = n - (y.exponent - d.exponent).abs) > 0) - m = BigDecimal.double_fig if m < BigDecimal.double_fig - sign = -sign - x1 = x2.mult(x1,n) - i += two - z *= (i-one) * i - d = sign * x1.div(z,m) - y += d - end - neg ? -y : y - end - - # Computes the cosine of x to the specified number of digits of precision. - # - # If x is infinite or NaN, returns NaN. - def cos(x, prec) - raise ArgumentError, "Zero or negative precision for cos" if prec <= 0 - return BigDecimal("NaN") if x.infinite? || x.nan? - n = prec + BigDecimal.double_fig - one = BigDecimal("1") - two = BigDecimal("2") - x = -x if x < 0 - if x > (twopi = two * BigMath.PI(prec)) - if x > 30 - x %= twopi - else - x -= twopi while x > twopi - end - end - x1 = one - x2 = x.mult(x,n) - sign = 1 - y = one - d = y - i = BigDecimal("0") - z = one - while d.nonzero? && ((m = n - (y.exponent - d.exponent).abs) > 0) - m = BigDecimal.double_fig if m < BigDecimal.double_fig - sign = -sign - x1 = x2.mult(x1,n) - i += two - z *= (i-one) * i - d = sign * x1.div(z,m) - y += d - end - y - end - - # Computes the arctangent of x to the specified number of digits of precision. - # - # If x is NaN, returns NaN. - def atan(x, prec) - raise ArgumentError, "Zero or negative precision for atan" if prec <= 0 - return BigDecimal("NaN") if x.nan? - pi = PI(prec) - x = -x if neg = x < 0 - return pi.div(neg ? -2 : 2, prec) if x.infinite? - return pi / (neg ? -4 : 4) if x.round(prec) == 1 - x = BigDecimal("1").div(x, prec) if inv = x > 1 - x = (-1 + sqrt(1 + x**2, prec))/x if dbl = x > 0.5 - n = prec + BigDecimal.double_fig - y = x - d = y - t = x - r = BigDecimal("3") - x2 = x.mult(x,n) - while d.nonzero? && ((m = n - (y.exponent - d.exponent).abs) > 0) - m = BigDecimal.double_fig if m < BigDecimal.double_fig - t = -t.mult(x2,n) - d = t.div(r,m) - y += d - r += 2 - end - y *= 2 if dbl - y = pi / 2 - y if inv - y = -y if neg - y - end - - # Computes the value of pi to the specified number of digits of precision. - def PI(prec) - raise ArgumentError, "Zero or negative argument for PI" if prec <= 0 - n = prec + BigDecimal.double_fig - zero = BigDecimal("0") - one = BigDecimal("1") - two = BigDecimal("2") - - m25 = BigDecimal("-0.04") - m57121 = BigDecimal("-57121") - - pi = zero - - d = one - k = one - w = one - t = BigDecimal("-80") - while d.nonzero? && ((m = n - (pi.exponent - d.exponent).abs) > 0) - m = BigDecimal.double_fig if m < BigDecimal.double_fig - t = t*m25 - d = t.div(k,m) - k = k+two - pi = pi + d - end - - d = one - k = one - w = one - t = BigDecimal("956") - while d.nonzero? && ((m = n - (pi.exponent - d.exponent).abs) > 0) - m = BigDecimal.double_fig if m < BigDecimal.double_fig - t = t.div(m57121,n) - d = t.div(k,m) - pi = pi + d - k = k+two - end - pi - end - - # Computes e (the base of natural logarithms) to the specified number of - # digits of precision. - def E(prec) - raise ArgumentError, "Zero or negative precision for E" if prec <= 0 - n = prec + BigDecimal.double_fig - one = BigDecimal("1") - y = one - d = y - z = one - i = 0 - while d.nonzero? && ((m = n - (y.exponent - d.exponent).abs) > 0) - m = BigDecimal.double_fig if m < BigDecimal.double_fig - i += 1 - z *= i - d = one.div(z,m) - y += d - end - y - end -end |