[ishan_ae]

Hello,

I have a question related to how the coefficients from resulting discretized system of equations are stored.

I noticed that there are several sparse matrix storage formats such as CSR(compressed sparse row) that are used in linear solver libraries such as lis(https://github.com/anishida/lis) and PETSc.

When the coefficients are calculated for the CFD system under study, are the algorithms modified, not Physics-wise but implementation-wise, so that the coefficients are stored in the desired storage format in, lets say N steps?

If not, then are the coefficients calculated, stored temporarily and then the coefficients converted into the matrix format? To me this seems like it will increase the memory usage and also will need at least t N+1 steps implementation-wise.

I do not have expert-level know-how about about C or C++ but in my opinion this also depends on how the libraries are built.

This is something which I wondered about because I am right now using C in my CFD learning process. I want to use existing linear solver libraries for my code and in the code documentation they have mentioned about different storage formats.

Based on your experience how is this usually done?