You may have had the same issue that I am having now. I upgraded my code to run in MPI, but the most challenging part is the writing the file for tecplot.
Since I am using MPI functions i,e: MPI_WRITE_ALL, the way the solution is written seems to be wrong. First of all, how do you specify the format in MPI_WRITE_ALL, and secondly and more important how do you manage the writing itself. Because, I usually use one zone and write in a do loop like:
do j=1, jmax
write(format, file) = x(i,j), y(i,j),u_old(i,j) and so forth
the problem here is that every rank will start writing from x(i,j). That is not a problem because I can consider the imax from the previous rank. The problem is that each rank will dump all the information from y(i,j) from zero to ymax. Here there is no a shortcut or quick fix because this is how tecplot requires to read the file.
How have you solve this inconvenience in MPI and tecplot? Suggestions, advice .... etc..