ENH: simulation.optimization.cost_function: L_LS classes rewritten, util.math.sparse.solve.*_substitution replaced by scipy.sparse.linalg.spsolve_triangular
ENH: simulation.optimization.cost_function: L_LS classes rewritten, util.math.sparse.solve.*_substitution replaced by scipy.sparse.linalg.spsolve_triangular

jor-/simulation