Zabbix

/*

** Copyright (C) 2001-2025 Zabbix SIA

**

** This program is free software: you can redistribute it and/or modify it under the terms of

** the GNU Affero General Public License as published by the Free Software Foundation, version 3.

**

** This program 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 Affero General Public License for more details.

**

** You should have received a copy of the GNU Affero General Public License along with this program.

** If not, see <https://www.gnu.org/licenses/>.

**/

​

#include "zbxalgo.h"

​

#include "zbxnum.h"

​

#define ZBX_MATH_EPSILON    (1e-6)

​

#define ZBX_IS_NAN(x)   ((x) != (x))

#define ZBX_VALID_MATRIX(m)     (0 < (m)->rows && 0 < (m)->columns && NULL != (m)->elements)

#define ZBX_MATRIX_EL(m, row, col)  ((m)->elements[(row) * (m)->columns + (col)])

#define ZBX_MATRIX_ROW(m, row)      ((m)->elements + (row) * (m)->columns)

​

typedef struct

{

    int rows;

    int columns;

    double  *elements;

}

zbx_matrix_t;

​

static void zbx_matrix_struct_alloc(zbx_matrix_t **pm)

{

    *pm = (zbx_matrix_t *)zbx_malloc(*pm, sizeof(zbx_matrix_t));

​

    (*pm)->rows = 0;

    (*pm)->columns = 0;

    (*pm)->elements = NULL;

}

​

static int  zbx_matrix_alloc(zbx_matrix_t *m, int rows, int columns)

{

    if (0 >= rows || 0 >= columns)

        goto error;

​

    m->rows = rows;

    m->columns = columns;

​

    m->elements = (double *)zbx_malloc(m->elements, sizeof(double) * rows * columns);

​

    return SUCCEED;

error:

    THIS_SHOULD_NEVER_HAPPEN;

​

    return FAIL;

}

​

static void zbx_matrix_free(zbx_matrix_t *m)

{

    if (NULL != m)

        zbx_free(m->elements);

​

    zbx_free(m);

}

​

static int  zbx_matrix_copy(zbx_matrix_t *dest, zbx_matrix_t *src)

{

    if (!ZBX_VALID_MATRIX(src))

        goto error;

​

    if (SUCCEED != zbx_matrix_alloc(dest, src->rows, src->columns))

        return FAIL;

​

    memcpy(dest->elements, src->elements, sizeof(double) * src->rows * src->columns);

    return SUCCEED;

error:

    THIS_SHOULD_NEVER_HAPPEN;

​

    return FAIL;

}

​

static int  zbx_identity_matrix(zbx_matrix_t *m, int n)

{

    if (SUCCEED != zbx_matrix_alloc(m, n, n))

        return FAIL;

​

    for (int i = 0; i < n; i++)

        for (int j = 0; j < n; j++)

            ZBX_MATRIX_EL(m, i, j) = (i == j ? 1.0 : 0.0);