> I have a memory problem with concatenating two matrices, > appending two matrices and copy matrix (mzd_submatrix) . The > problem is happened in case of I have two big matrices and during > the concatenation or the appending process I have twice the size in > the memory which terminates the main process and the program > (reach to the memory limit). I tried to make reallocation to the > matrix to make the concatenation and the appending processes > using a little bit less memory. But I have a problem > with this code.

> After performing mzd_reduce_m4ri on the matrix M. I removed the > zero row at the end by using the following statement: > reallocating(M, rank, M->ncols); > In the multiplication process when I tried to append M with other > zero matrix T that has the same number of columns by the > following statement: > M = mzd_append(NULL, M, T);

> the program terminated without printing any error message. But I > think the program stopped because of it can not access >M->values[some index].

Bottomline: implement mzd_realloc(A, m, n) which restricts A to the first m rows and n columns in place.