dspl/ellip__asn_8c_source.html

/*

* Copyright (c) 2015-2024 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"


#ifdef DOXYGEN_ENGLISH


#endif

#ifdef DOXYGEN_RUSSIAN


#endif

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;

}