Re: [firedrake] problem solving a linear system

On 21/06/17 15:58, Francis Poulin wrote:

Thank you Andrew. We will look at that closely.

But if we are solving a linear system using LU then we shouldn't be using snes though should we? That is the error we are getting in convergence.

We always use SNES, but for linear problems it is set to ksponly (so it's equivalent to just using KSP). That error looks like potentially you had a zero pivot in the LU factorisation? What does running the solve with: "ksp_converged_reason": True, "snes_converged_reason": True, (in addition to your other parameters) say? Lawrence