libdspl-2.0/dspl/src/ellipj.c

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9.9 KiB
C

/*
* Copyright (c) 2015-2019 Sergey Bakhurin
* Digital Signal Processing Library [http://dsplib.org]
*
* This file is part of DSPL.
*
* is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* DSPL is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Foobar. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "dspl.h"
/*****************************************************************************
* inverse cd function
******************************************************************************/
int DSPL_API ellip_acd(double* w, int n, double k, double* u)
{
double lnd[ELLIP_ITER], t;
int i, m;
if(!u || !w)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
ellip_landen(k,ELLIP_ITER, lnd);
for(m = 0; m < n; m++)
{
u[m] = w[m];
for(i = 1; i < ELLIP_ITER; i++)
{
t = lnd[i-1]*u[m];
t *= t;
t = 1.0 + sqrt(1.0 - t);
u[m] = 2.0 * u[m] / (t+t*lnd[i]);
}
u[m] = 2.0 * acos(u[m]) / M_PI;
}
return RES_OK;
}
/*****************************************************************************
* inverse cd function
******************************************************************************/
int DSPL_API ellip_acd_cmplx(complex_t* w, int n, double k, complex_t* u)
{
double lnd[ELLIP_ITER], t;
complex_t tmp0, tmp1;
int i, m;
if(!u || !w)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
ellip_landen(k,ELLIP_ITER, lnd);
for(m = 0; m < n; m++)
{
RE(u[m]) = RE(w[m]);
IM(u[m]) = IM(w[m]);
for(i = 1; i < ELLIP_ITER; i++)
{
RE(tmp0) = lnd[i-1]*RE(u[m]);
IM(tmp0) = lnd[i-1]*IM(u[m]);
RE(tmp1) = 1.0 - CMRE(tmp0, tmp0);
IM(tmp1) = - CMIM(tmp0, tmp0);
sqrt_cmplx(&tmp1, 1, &tmp0);
RE(tmp0) += 1.0;
RE(tmp1) = RE(tmp0) * (1.0 + lnd[i]);
IM(tmp1) = IM(tmp0) * (1.0 + lnd[i]);
t = 2.0 / ABSSQR(tmp1);
RE(tmp0) = t * CMCONJRE(u[m], tmp1);
IM(tmp0) = t * CMCONJIM(u[m], tmp1);
RE(u[m]) = RE(tmp0);
IM(u[m]) = IM(tmp0);
}
acos_cmplx(&tmp0, 1, u+m);
t = 2.0 / M_PI;
RE(u[m]) *= t;
IM(u[m]) *= t;
}
return RES_OK;
}
/*****************************************************************************
* inverse sn function
******************************************************************************/
int DSPL_API ellip_asn(double* w, int n, double k, double* u)
{
double lnd[ELLIP_ITER], t;
int i, m;
if(!u || !w)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
ellip_landen(k,ELLIP_ITER, lnd);
for(m = 0; m < n; m++)
{
u[m] = w[m];
for(i = 1; i < ELLIP_ITER; i++)
{
t = lnd[i-1]*u[m];
t *= t;
t = 1.0 + sqrt(1.0 - t);
u[m] = 2.0 * u[m] / (t+t*lnd[i]);
}
u[m] = 2.0 * asin(u[m]) / M_PI;
}
return RES_OK;
}
/*****************************************************************************
* inverse sn function
******************************************************************************/
int DSPL_API ellip_asn_cmplx(complex_t* w, int n, double k, complex_t* u)
{
double lnd[ELLIP_ITER], t;
complex_t tmp0, tmp1;
int i, m;
if(!u || !w)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
ellip_landen(k,ELLIP_ITER, lnd);
for(m = 0; m < n; m++)
{
RE(u[m]) = RE(w[m]);
IM(u[m]) = IM(w[m]);
for(i = 1; i < ELLIP_ITER; i++)
{
RE(tmp0) = lnd[i-1]*RE(u[m]);
IM(tmp0) = lnd[i-1]*IM(u[m]);
RE(tmp1) = 1.0 - CMRE(tmp0, tmp0);
IM(tmp1) = - CMIM(tmp0, tmp0);
sqrt_cmplx(&tmp1, 1, &tmp0);
RE(tmp0) += 1.0;
RE(tmp1) = RE(tmp0) * (1.0 + lnd[i]);
IM(tmp1) = IM(tmp0) * (1.0 + lnd[i]);
t = 2.0 / ABSSQR(tmp1);
RE(tmp0) = t * CMCONJRE(u[m], tmp1);
IM(tmp0) = t * CMCONJIM(u[m], tmp1);
RE(u[m]) = RE(tmp0);
IM(u[m]) = IM(tmp0);
}
asin_cmplx(&tmp0, 1, u+m);
t = 2.0 / M_PI;
RE(u[m]) *= t;
IM(u[m]) *= t;
}
return RES_OK;
}
/*****************************************************************************
* Elliptic cd function
******************************************************************************/
int DSPL_API ellip_cd(double* u, int n, double k, double* y)
{
double lnd[ELLIP_ITER];
int i, m;
if(!u || !y)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
ellip_landen(k,ELLIP_ITER, lnd);
for(m = 0; m < n; m++)
{
y[m] = cos(u[m] * M_PI * 0.5);
for(i = ELLIP_ITER-1; i>0; i--)
{
y[m] = (1.0 + lnd[i]) / (1.0 / y[m] + lnd[i]*y[m]);
}
}
return RES_OK;
}
/*****************************************************************************
* Elliptic cd function
******************************************************************************/
int DSPL_API ellip_cd_cmplx(complex_t* u, int n, double k, complex_t* y)
{
double lnd[ELLIP_ITER], t;
int i, m;
complex_t tmp;
if(!u || !y)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
ellip_landen(k,ELLIP_ITER, lnd);
for(m = 0; m < n; m++)
{
RE(tmp) = RE(u[m]) * M_PI * 0.5;
IM(tmp) = IM(u[m]) * M_PI * 0.5;
cos_cmplx(&tmp, 1, y+m);
for(i = ELLIP_ITER-1; i>0; i--)
{
t = 1.0 / ABSSQR(y[m]);
RE(tmp) = RE(y[m]) * t + RE(y[m]) * lnd[i];
IM(tmp) = -IM(y[m]) * t + IM(y[m]) * lnd[i];
t = (1.0 + lnd[i]) / ABSSQR(tmp);
RE(y[m]) = RE(tmp) * t;
IM(y[m]) = -IM(tmp) * t;
}
}
return RES_OK;
}
/*****************************************************************************
* Landen transform
******************************************************************************/
int DSPL_API ellip_landen(double k, int n, double* y)
{
int i;
y[0] = k;
if(!y)
return ERROR_PTR;
if(n < 1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
for(i = 1; i < n; i++)
{
y[i] = y[i-1] / (1.0 + sqrt(1.0 - y[i-1] * y[i-1]));
y[i] *= y[i];
}
return RES_OK;
}
/*****************************************************************************
* Elliptic modular equation
******************************************************************************/
int DSPL_API ellip_modulareq(double rp, double rs, int ord, double *k)
{
double ep, es, ke, kp, t, sn;
int i, L, r;
if(rp < 0 || rp == 0)
return ERROR_FILTER_RP;
if(rs < 0 || rs == 0)
return ERROR_FILTER_RS;
if(ord < 1)
return ERROR_FILTER_ORD;
if(!k)
return ERROR_PTR;
ep = sqrt(pow(10.0, rp*0.1)-1.0);
es = sqrt(pow(10.0, rs*0.1)-1.0);
ke = ep/es;
ke = sqrt(1.0 - ke*ke);
r = ord % 2;
L = (ord-r)/2;
kp = 1.0;
for(i = 0; i < L; i++)
{
t = (double)(2*i+1) / (double)ord;
ellip_sn(&t, 1, ke, &sn);
sn*=sn;
kp *= sn*sn;
}
kp *= pow(ke, (double)ord);
*k = sqrt(1.0 - kp*kp);
return RES_OK;
}
/*****************************************************************************
* Elliptic rational function
******************************************************************************/
int DSPL_API ellip_rat(double* w, int n, int ord, double k, double* u)
{
double t, xi, w2, xi2, k2;
int i, m, r, L;
if(!u || !w)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
r = ord%2;
L = (ord-r)/2;
if(r)
memcpy(u, w, n*sizeof(double));
else
{
for(m = 0; m < n; m++)
{
u[m] = 1.0;
}
}
k2 = k*k;
for(i = 0; i < L; i++)
{
t = (double)(2*i+1) / (double)ord;
ellip_cd(&t, 1, k, &xi);
xi2 = xi*xi;
for(m = 0; m < n; m++)
{
w2 = w[m]*w[m];
u[m] *= (w2 - xi2) / (1.0 - w2 * k2 * xi2);
u[m] *= (1.0 - k2*xi2) / (1.0 - xi2);
}
}
return RES_OK;
}
/*****************************************************************************
* Elliptic sn function
******************************************************************************/
int DSPL_API ellip_sn(double* u, int n, double k, double* y)
{
double lnd[ELLIP_ITER];
int i, m;
if(!u || !y)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
ellip_landen(k,ELLIP_ITER, lnd);
for(m = 0; m < n; m++)
{
y[m] = sin(u[m] * M_PI * 0.5);
for(i = ELLIP_ITER-1; i>0; i--)
{
y[m] = (1.0 + lnd[i]) / (1.0 / y[m] + lnd[i]*y[m]);
}
}
return RES_OK;
}
/*****************************************************************************
* Elliptic sn function
******************************************************************************/
int DSPL_API ellip_sn_cmplx(complex_t* u, int n, double k, complex_t* y)
{
double lnd[ELLIP_ITER], t;
int i, m;
complex_t tmp;
if(!u || !y)
return ERROR_PTR;
if(n<1)
return ERROR_SIZE;
if(k < 0.0 || k>= 1.0)
return ERROR_ELLIP_MODULE;
ellip_landen(k,ELLIP_ITER, lnd);
for(m = 0; m < n; m++)
{
RE(tmp) = RE(u[m]) * M_PI * 0.5;
IM(tmp) = IM(u[m]) * M_PI * 0.5;
sin_cmplx(&tmp, 1, y+m);
for(i = ELLIP_ITER-1; i>0; i--)
{
t = 1.0 / ABSSQR(y[m]);
RE(tmp) = RE(y[m]) * t + RE(y[m]) * lnd[i];
IM(tmp) = -IM(y[m]) * t + IM(y[m]) * lnd[i];
t = (1.0 + lnd[i]) / ABSSQR(tmp);
RE(y[m]) = RE(tmp) * t;
IM(y[m]) = -IM(tmp) * t;
}
}
return RES_OK;
}