diff options
Diffstat (limited to '2.3-1/src/c/auxiliaryFunctions/rand/i8rands.c')
-rw-r--r-- | 2.3-1/src/c/auxiliaryFunctions/rand/i8rands.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/2.3-1/src/c/auxiliaryFunctions/rand/i8rands.c b/2.3-1/src/c/auxiliaryFunctions/rand/i8rands.c new file mode 100644 index 00000000..e9b30a33 --- /dev/null +++ b/2.3-1/src/c/auxiliaryFunctions/rand/i8rands.c @@ -0,0 +1,53 @@ +/* Copyright (C) 2016 - IIT Bombay - FOSSEE + + This file must be used under the terms of the CeCILL. + This source file is licensed as described in the file COPYING, which + you should have received as part of this distribution. The terms + are also available at + http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt + Author: Mushir + Organization: FOSSEE, IIT Bombay + Email: toolbox@scilab.in +*/ + +#include "rand.h" +#include <stdio.h> + +double i8rands(void) +{ + +int m=1; +const int itwo=2; +static int m2=0,halfm=0,ia=0,ic=0,mic=0,iy=0; +static double s=0.0; +if(m2==0) +{ + /*if first entry,compute machine integer word length*/ + while(m>m2) + { + m2=m; + m=itwo*m2; + } + halfm = m2; + /* compute multiplier and increment for linear congruential methos */ + ia = 8*(int)(halfm*atan(1.0)/8.0) + 5; + ic = 2*(int)(halfm*(0.5-sqrt(3.0)/6.0)) +1; + mic = (m2 - ic) + m2; + /* s is the scale factor for converting to floating point*/ + s = 0.5/halfm; + +} + +/* compute next random number */ + iy = iy*ia; +/* the following statement is for computers which do not allow interger overflow on addition*/ +if(iy > mic) iy = (iy - m2) - m2; + iy = iy + ic; + + /* the following statement is for computers where the word length for addition is greater than for multiplication */ + if(iy/2 > m2) iy = (iy - m2) - m2; + /* the following statement is for computers where integer overflow affects the sign bit */ + if(iy < 0) iy = (iy + m2) + m2; + return (double)iy*s; + +} |