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, size_t *dims, 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 exmaple, 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,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,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,COMPRESSION_NONE);
             Mat_VarFree(matvar);
         }

         Mat_Close(matfp);
         return EXIT_SUCCESS;
     }

SEE ALSO

     Mat_VarCreateStruct(3), Mat_VarFree(3), Mat_VarWrite(3)