[petsc-dev] SNES takes 50 newton iterations

[Hesameddin Ilatikhameneh]

Hello,

I want to minimize a simple energy equation (E = E(x0,x1,...,xN)) using nonlinear solver SNES. This way SNES equation F(x) = dE/dxi = 0 and jacobian is J = dF/dx = d2E/dx2. I have attached a report explaining the problem and how I implemented it.

The energy is related to 1D chain of balls connected with springs and the final answer is that all balls spaced equal to ideal distance. 

My problem is that SNES takes near 30-50 newton iterations to converge which seems to be too much for such a simple problem.
I have also attached the code and appreciate your help on this.

Thanks
Hesam
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