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MAT_VARCREATE(3)      DragonFly 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, 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)

DragonFly 6.5-DEVELOPMENT       March 18, 2012       DragonFly 6.5-DEVELOPMENT