Many of things MathGL do in parallel by default (if MathGL was built with pthread). However, there is function which set the number of threads to be used.
int mgl_set_num_thr (int n) ¶Set the number of threads to be used by MathGL. If n<1 then the number of threads is set as maximal number of processors (cores). If n=1 then single thread will be used (this is default if pthread was disabled).
Another option is combining bitmap image (taking into account Z-ordering) from different instances of mglGraph. This method is most appropriate for computer clusters when the data size is so large that it exceed the memory of single computer node.
mglGraph: int Combine (const mglGraph &g) ¶int mgl_combine_gr (HMGL gr, HMGL g) ¶Combine drawing from instance g with gr (or with this) taking into account Z-ordering of pixels. The width and height of both instances must be the same.