aux.fisch               Generate a 2-dimensional discrete Poisson
                        matrix
lsolve.bicg             Biconjugate Gradient method
lsolve.bicgstab         Biconjugate Gradient Stabilized Method
lsolve.cg               Conjugate Gradient method
lsolve.cgs              Conjugate Gradient Squared method
lsolve.cheby            Chebyshev Method
lsolve.gmres            Generalized Minimal Residual method
lsolve.gs               Gauss-Seidel method
lsolve.jacobi           Jacobi method
lsolve.qmr              Quasi Minimal Residual Method
lsolve.sor              Successive Over-Relaxation method
lsolve.ssor             Symmetric Successive Over-Relaxation method
