I am looking for simple GMRES implementations. Unfortunately, I have a few requirements:
- should be C or Fortran, Fortran preferred
- needs a license that permits inclusion in an MIT/BSD licensed package
- needs to deal with complex data
So far, the "templates" code on netlib seemed to fit well. However, it doesn't deal with complex data (although I think changing a few declarations from real to complex could fix that), and also it obviously implements operations better left to BLAS (I think e.g. this code's Givens rotations that'd probably better be
drot() calls). Another alternative, PETSc, seems overkill.
I am looking forward to your suggestions. Thank you!