Hello, I have a question about rank of matrix. At the problem Au = b,
In my case, sometimes global matrix A is not full rank. In this case, the global matrix A is more likely to be singular, and if it becomes singular, the problem cannot be solved even in the case of the direct solver. I haven't solved the problem with an iterative solver yet, but I would like to ask someone who has experienced this kind of problem. 1. If it is not full rank, is there a numerical technique to solve it by catching rows and columns with empty ranks in advance? 2.If anyone has solved it in a different way than the above numerical analysis method, please tell me your experience. Thanks, Hyung Kim
