diff options
| -rw-r--r-- | AUTHORS | 1 | ||||
| -rw-r--r-- | src/library.js | 57 | ||||
| -rwxr-xr-x | tests/runner.py | 18 |
3 files changed, 76 insertions, 0 deletions
@@ -40,4 +40,5 @@ a license to everyone to use it as detailed in LICENSE.) * Lars Schneider <lars.schneider@autodesk.com> (copyright owned by Autodesk, Inc.) * Joel Martin <github@martintribe.org> * Manuel Wellmann <manuel.wellmann@autodesk.com> (copyright owned by Autodesk, Inc.) +* Xuejie xiao <xxuejie@gmail.com> diff --git a/src/library.js b/src/library.js index eb4aad40..ea43609d 100644 --- a/src/library.js +++ b/src/library.js @@ -5127,6 +5127,63 @@ LibraryManager.library = { atan2f: 'Math.atan2', exp: 'Math.exp', expf: 'Math.exp', + + // The erf and erfc functions are inspired from + // http://www.digitalmars.com/archives/cplusplus/3634.html + // and mruby source code at + // https://github.com/mruby/mruby/blob/master/src/math.c + erfc: function (x) { + var MATH_TOLERANCE = 1E-12; + var ONE_SQRTPI = 0.564189583547756287; + var a = 1; + var b = x; + var c = x; + var d = x * x + 0.5; + var n = 1.0 + var q1, q2, t; + + if (Math.abs(x) < 2.2) { + return 1.0 - _erf(x); + } + if (x < 0) { + return 2.0 - _erfc(-x); + } + do { + t = a * n + b * x; + a = b; + b = t; + t = c * n + d * x; + c = d; + d = t; + n += 0.5; + q1 = q2; + q2 = b / d; + } while (Math.abs(q1 - q2) / q2 > MATH_TOLERANCE); + return (ONE_SQRTPI * Math.exp(- x * x) * q2); + }, + erfcf: 'erfcf', + erf: function (x) { + var MATH_TOLERANCE = 1E-12; + var TWO_SQRTPI = 1.128379167095512574; + var sum = x; + var term = x; + var xsqr = x*x; + var j = 1; + + if (Math.abs(x) > 2.2) { + return 1.0 - _erfc(x); + } + do { + term *= xsqr / j; + sum -= term / (2 * j + 1); + ++j; + term *= xsqr / j; + sum += term / (2 * j + 1); + ++j; + } while (Math.abs(term / sum) > MATH_TOLERANCE); + return (TWO_SQRTPI * sum); + }, + erff: 'erf', log: 'Math.log', logf: 'Math.log', sqrt: 'Math.sqrt', diff --git a/tests/runner.py b/tests/runner.py index de964809..99af7109 100755 --- a/tests/runner.py +++ b/tests/runner.py @@ -1450,6 +1450,24 @@ c5,de,15,8a ''' self.do_run(src, '*3.14,-3.14,1,0,0,0,1,0,1,1,0,2,3,0.0,1.0,0.0,1.0*') + def test_erf(self): + src = ''' + #include <math.h> + #include <stdio.h> + int main() + { + printf("%1.6f, %1.6f, %1.6f, %1.6f, %1.6f, %1.6f\\n", + erf(1.0), + erf(3.0), + erf(-1.0), + erfc(1.0), + erfc(3.0), + erfc(-1.5)); + return 0; + } + ''' + self.do_run(src, '0.842701, 0.999978, -0.842701, 0.157299, 0.000022, 1.966105') + def test_math_hyperbolic(self): src = open(path_from_root('tests', 'hyperbolic', 'src.c'), 'r').read() expected = open(path_from_root('tests', 'hyperbolic', 'output.txt'), 'r').read() |