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Diffstat (limited to '2.3-1/src/c/signalProcessing/%sn/dmodsns.c')
| -rw-r--r-- | 2.3-1/src/c/signalProcessing/%sn/dmodsns.c | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/2.3-1/src/c/signalProcessing/%sn/dmodsns.c b/2.3-1/src/c/signalProcessing/%sn/dmodsns.c new file mode 100644 index 00000000..06d0a6f0 --- /dev/null +++ b/2.3-1/src/c/signalProcessing/%sn/dmodsns.c @@ -0,0 +1,93 @@ +/* Copyright (C) 2017 - 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: Ankit Raj + Organization: FOSSEE, IIT Bombay + Email: toolbox@scilab.in + Reference:- Abramowitz, Milton and Stegun, Irene A + Handbook of Mathematical Functions, Dover, 1965 + Chapter 16 (Sections 16.4, 16.13 and 16.15) + Link for FORTRAN code:-http://www.aip.de/groups/soe/local/numres/bookfpdf/f6-11.pdf +*/ + +#include<stdio.h> +#include<math.h> +#define CA 0.0003 +#include "modsn.h" +double dmodsns(double uu, double emmc) +{ + double a,b,c,d,emc,u; + double em[14],en[14]; + int i,ii,l,bo; + double sn,cn,dn; + emc=1-emmc; + u=uu; + if(emc) + { + bo=(emc<0.0); + if(bo) + { + d=1.0-emc; + emc/=-1.0/d; + u*=(d=sqrt(d)); + } + a=1.0; + dn=1.0; + for(i=1;i<=13;i++) + { + l=i; + em[i]=a; + en[i]=(emc=sqrt(emc)); + c=0.5*(a+emc); + if(fabs(a-emc)<=CA*a)break; + emc*=a; + a=c; + } + u*=c; + sn=sin(u); + cn=cos(u); + if(sn) + { + a=cn/sn; + c*=a; + for(ii=l;ii>=1;ii--) + { + b=em[ii]; + a*=c; + c*=dn; + dn=(en[ii]+a)/(b+a); + a=c/b; + } + a=1.0/sqrt(c*c+1.0); + sn=(sn>=0.0?a:-a); + cn=c*(sn); + } + if(bo) + { + a=dn; + dn=cn; + cn=a; + sn/=d; + } + } + else + { + cn=1.0/cosh(u); + dn=cn; + sn=tanh(u); + } + return sn; +} +/* +int main() +{ + double u,k; + u=4; + k=0.7; + sn(u,k); +} +*/ |