In the `c++` program that I am trying to write I would need to update a 2D array and then plot it (for plotting I have been using `gnuplot`) for a pretty big number of times.
I would like, if possible, to avoid having a huge file in which I would write the matrix for every step of the evolution to plot everything afterwards.

My intention was to do a `gnuplot` script able to run the program to evolve the matrix once and then print it and then iterate. But to do so I would need to give to the program access to the matrix calculated in the prior step and I cannot figure out an efficient way to do it. Being able to keep the matrix in memory between runs and passing only a pointer from one step to the other seems fast but I do not know if it is possible.

Do you know if it is possible to keep a variable in memory between runs or do you have alternative suggestions?

Thanks.