how to save sparse matrix

You can save a sparse matrix inside of a GAUSS Data Archive (GDA). Here is a simple example:

//Declare 'a' to be a sparse matrix
sparse matrix a;

//Create sparse matrix with random data
a = densetosp(rndu(10, 5), 0.25);

//Save sparse matrix 'a' to file 'mysparsedata.gda'
ret = gdaSave("mysparsedata.gda", "a", 0, 1, 0);

//Declare 'a_copy' to be a sparse matrix
sparse matrix a_copy;

//Load sparse data from 'mysparsedata.gda'
a_copy = gdaReadSparse("mysparsedata.gda", "a");

if (a == a_copy);
    print "success!";
else;
    print "matrices are different";
endif;