table of contents
MAT_VARCREATE(3) | Library Functions Manual | MAT_VARCREATE(3) |
NAME¶
Mat_VarCreate
—
Creates a MAT variable structure.
SYNOPSIS¶
#include
<matio.h>
matvar_t *
Mat_VarCreate
(const char *name,
enum matio_classes class_type, enum
matio_types data_type, int rank,
const size_t *dims, const void
*data, int opt);
DESCRIPTION¶
The
Mat_VarCreate
()
function creates a MAT structure variable named name
that can be written to a MAT file. The class_type
argument specifies the class of the variable, and the
data_type argument specifies the type of the data. For
example, a double-precision class would use
MAT_C_DOUBLE
for the class type and
MAT_T_DOUBLE
for the data type. In some instances,
the data type may not match the class type. For example, an array of
integers can be written in the double-precision class by using
MAT_T_INT32
for data_type.
The rank argument specifies how many dimensions the data has. The minimum rank is 2. The number of elements in each dimension is specified in the array dims.
The data argument is a pointer to the variable data. The pointer is typically a pointer to a numeric array (e.g. double, float, int, etc.) for real variables. For complex variables, the pointer is a pointer to a mat_complex_split_t which contains pointers to the real and imaginary data as fields of the structure. For sparse variables, the pointer should be a mat_sparse_t *.
RETURN VALUES¶
If the variable was successfully created, a pointer to the
variable is returned. Otherwise NULL is returned. The variable should be
free'd when no longer needed using
Mat_VarFree
().
EXAMPLES¶
The example program below creates a MAT file named test.mat, and writes two real numeric variables x and y and a complex variable z to the file.
#include <stdlib.h> #include <stdio.h> #include "matio.h" int main(int argc,char **argv) { mat_t *matfp; matvar_t *matvar; size_t dims[2] = {10,1}; double x[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9,10}, y[10] = {11,12,13,14,15,16,17,18,19,20}; struct mat_complex_split_t z = {x, y}; matfp = Mat_CreateVer("test.mat", NULL, MAT_FT_DEFAULT); if ( NULL == matfp ) { fprintf(stderr, "Error creating MAT file return EXIT_FAILURE; } matvar = Mat_VarCreate("x", MAT_C_DOUBLE, MAT_T_DOUBLE, 2, dims, x, 0); if ( NULL == matvar ) { fprintf(stderr, "Error creating variable for 'x'0); } else { Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_NONE); Mat_VarFree(matvar); } matvar = Mat_VarCreate("y", MAT_C_DOUBLE, MAT_T_DOUBLE, 2, dims, y, 0); if ( NULL == matvar ) { fprintf(stderr, "Error creating variable for 'y'0); } else { Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_NONE); Mat_VarFree(matvar); } matvar = Mat_VarCreate("z", MAT_C_DOUBLE, MAT_T_DOUBLE, 2, dims, &z, MAT_F_COMPLEX); if ( NULL == matvar ) { fprintf(stderr, "Error creating variable for 'z'0); } else { Mat_VarWrite(matfp, matvar, MAT_COMPRESSION_NONE); Mat_VarFree(matvar); } Mat_Close(matfp); return EXIT_SUCCESS; }
SEE ALSO¶
November 20, 2023 | Debian |