finished gpu module docs for matrix operations

doc/gpu_data_structures.tex

@@ -9,5 +9,5 @@ Creates continuous matrix in GPU memory.
 \cvarg{rows}{Row count.}
 \cvarg{cols}{Column count.}
 \cvarg{type}{Type of the matrix.}
-\cvarg{m}{Destination matrix. Will be reshaped only if it has proper type and area ($rows \times cols$).}
+\cvarg{m}{Destination matrix. Will be only reshaped if it has proper type and area (\texttt{rows} $\times$ \texttt{cols}).}
 \end{description}