dspl/logspace_8c_source.html

/*

* Copyright (c) 2015-2024 Sergey Bakhurin

* Digital Signal Processing Library [http://dsplib.org]

*

* This file is part of libdspl-2.0.

*

* is free software: you can redistribute it and/or modify

* it under the terms of the GNU Lesser    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 Lesser General Public License

* along with Foobar.    If not, see <http://www.gnu.org/licenses/>.

*/


#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "dspl.h"


#ifdef DOXYGEN_ENGLISH


#endif

#ifdef DOXYGEN_RUSSIAN


#endif

int DSPL_API logspace(double x0, double x1, int n, int type, double* x)

{

    double mx, a, b;

    int k;


    if(n < 2)

        return ERROR_SIZE;

    if(!x)

        return ERROR_PTR;


    a = pow(10.0, x0);

    b = pow(10.0, x1);


    switch (type)

    {

        case DSPL_SYMMETRIC:

            mx = pow(b/a, 1.0/(double)(n-1));

            x[0] = a;

            for(k = 1; k < n; k++)

                x[k] = x[k-1] * mx;

            break;

        case DSPL_PERIODIC:

            mx = pow(b/a, 1.0/(double)n);

            x[0] = a;

            for(k = 1; k < n; k++)

                x[k] = x[k-1] * mx;

            break;

        default:

            return ERROR_SYM_TYPE;

    }

    return RES_OK;

}