Comment out line search in Newton iteration

The line search seems to just slow down simulations, not make them more
robust (which was the hope). It is probably better to just fail faster
and decrease the timestep, etc.

moment_kinetics/src/nonlinear_solvers.jl

@@ -478,43 +478,44 @@ old_precon_iterations = nl_solver_params.precon_iterations[]
         if isnan(residual_norm)
             error("NaN in Newton iteration at iteration $counter")
         end
-        if residual_norm > previous_residual_norm
-            # Do a line search between x and x+delta_x to try to find an update that does
-            # decrease residual_norm
-            s = 0.5
-            while s > 1.0e-2
-                parallel_map(solver_type, (x,delta_x,s) -> x + s * delta_x, w, x, delta_x, s)
-                residual_func!(residual, x)
-                residual_norm = distributed_norm(solver_type, residual, norm_params...)
-                if residual_norm ≤ previous_residual_norm
-                    break
-                end
-                s *= 0.5
-            end
-
-            #if residual_norm > previous_residual_norm
-            #    # Failed to find a point that decreases the residual, so try a negative
-            #    # step
-            #    s = -1.0e-5
-            #    parallel_map(solver_type, (x,delta_x,s) -> x + s * delta_x, w, x, delta_x, s)
-            #    residual_func!(residual, x)
-            #    residual_norm = distributed_norm(solver_type, residual, norm_params...)
-            #    if residual_norm > previous_residual_norm
-            #        # That didn't work either, so just take the full step and hope for
-            #        # convergence later
-            #        parallel_map(solver_type, (x,delta_x,s) -> x + s * delta_x, w, x, delta_x, s)
-            #        residual_func!(residual, x)
-            #        residual_norm = distributed_norm(solver_type, residual, norm_params...)
-            #    end
-            #end
-            if residual_norm > previous_residual_norm
-                # Line search didn't work, so just take the full step and hope for
-                # convergence later
-                parallel_map(solver_type, (x,delta_x,s) -> x + s * delta_x, w, x, delta_x, s)
-                residual_func!(residual, x)
-                residual_norm = distributed_norm(solver_type, residual, norm_params...)
-            end
-        end
+#        if residual_norm > previous_residual_norm
+#            # Do a line search between x and x+delta_x to try to find an update that does
+#            # decrease residual_norm
+#            s = 0.5
+#            while s > 1.0e-2
+#                parallel_map(solver_type, (x,delta_x,s) -> x + s * delta_x, w, x, delta_x, s)
+#                residual_func!(residual, x)
+#                residual_norm = distributed_norm(solver_type, residual, norm_params...)
+#                if residual_norm ≤ previous_residual_norm
+#                    break
+#                end
+#                s *= 0.5
+#            end
+#            println("line search s ", s)
+#
+#            #if residual_norm > previous_residual_norm
+#            #    # Failed to find a point that decreases the residual, so try a negative
+#            #    # step
+#            #    s = -1.0e-5
+#            #    parallel_map(solver_type, (x,delta_x,s) -> x + s * delta_x, w, x, delta_x, s)
+#            #    residual_func!(residual, x)
+#            #    residual_norm = distributed_norm(solver_type, residual, norm_params...)
+#            #    if residual_norm > previous_residual_norm
+#            #        # That didn't work either, so just take the full step and hope for
+#            #        # convergence later
+#            #        parallel_map(solver_type, (x,delta_x,s) -> x + s * delta_x, w, x, delta_x, s)
+#            #        residual_func!(residual, x)
+#            #        residual_norm = distributed_norm(solver_type, residual, norm_params...)
+#            #    end
+#            #end
+#            if residual_norm > previous_residual_norm
+#                # Line search didn't work, so just take the full step and hope for
+#                # convergence later
+#                parallel_map(solver_type, (x,delta_x,s) -> x + s * delta_x, w, x, delta_x, s)
+#                residual_func!(residual, x)
+#                residual_norm = distributed_norm(solver_type, residual, norm_params...)
+#            end
+#        end
         parallel_map(solver_type, (w) -> w, x, w)
         previous_residual_norm = residual_norm