[petsc-users] Guidance on using Tao for unconstrained minimization

[Ellen M. Price]

Hello PETSc users!

I am using Tao for an unconstrained minimization problem. I have found
that CG works better than the other types for this application. After
about 85 iterations, I get an error about line search failure. I'm not
clear on what this means, or how I could mitigate the problem, and
neither the manual nor FAQ give any guidance. Can anyone suggest things
I could try to help the method converge? I have function and gradient
info, but no Hessian.

Thanks,
Ellen Price