how to build matrices for the lib

[nibblelab]

Hi,

I'm trying to build new matrices to use in amgcl. In the code, the lib reads matrices in CRS/CSR format in a binary file using the method amgcl::io::read_crs while the RHS vector, also in a binary file, is read with amgcl::io::read_dense.

How are those binary files organized?

For example, the matrix file could have an integer number describing the number of columns, followed by an integer number describing the number of rows, followed by a sequence of doubles describing the values of size non-zeros (a parameter), followed by a sequence of integers describing the column index, followed by a sequence of integers describing the row index. With that organization, the file would be structured like: int|int|double ..... double|double .... double|double

Are there any tutorials or instructions regarding how to create the matrices and RHS vectors for use in amgcl::io::read_crs and amgcl::io::read_dense?

[ddemidov]

See the poisson equation assembly example here: https://amgcl.readthedocs.io/en/latest/examples.html. The binary format used with read_dense is not standard in any way, it just reads the CRS vectors (ptr, col, and val) from a raw binary file.

[nibblelab]

Thank you.

I'll take a look at the example you listed.