GCG supports all file formats supported by SCIP to read in problems, solution, etc. The original problem can for example be read in as an .lp, .mps, or .cip file.
If GCG is not able to automatically detect a structure suitable to perform a Dantzig-Wolfe reformulation, you need to specify the structure yourself and make it available to GCG. There are some file formats for structure information. If in doubt, we recommend the
blk format which are documented in reader_dec.h and reader_blk.h, respectively.
You can find examples for
dec as well as
blk files in the