[petsc-users] Really Really Really Weird SNES behaviour

[subramanya sadasiva]

Hi, I am observing some really really really weird SNES behavior in my SNESVI code called through Libmesh. This behaviour appeared after I changed some initial conditions and only happens in an optimized build. I am running this code on a Macbook pro running os x 10.8.. 
When the debug code is run, the residuals computed for the initial conditions provided give norms which are of the expected magnitude.. so the SNES_Monitor output is, 
solving the cahn hilliard time step  0 SNES Function norm 8.223262421671e-01  1 SNES Function norm 3.793806858333e-03Nonlinear solve did not converge due to DIVERGED_MAX_IT iterations 1
The output from SNES_Monitor with the optimized code on the other hand is, 
solving the cahn hilliard time step  0 SNES Function norm 5.153882032022e+19  1 SNES Function norm 1.446612980133e+19Nonlinear solve did not converge due to DIVERGED_MAX_IT iterations 1

Absolutely nothing else has changed in the code except that one code is built with a debugging and one with an optimized version of the code. 
Any ideas?Subramanya 		 	   		  
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