Added modular Midpoint and added EulerProp

include/ascent/integrators_modular/Euler.h

@@ -20,6 +20,15 @@ namespace asc
 {
  namespace modular
  {
+ template <class value_t>
+ struct EulerProp : public Propagator<value_t>
+ {
+ void operator()(State& state, const value_t dt) override
+ {
+ *state.x += dt * *state.xd;
+ }
+ };
+
  template <typename value_t>
  struct Euler
  {

include/ascent/integrators_modular/Midpoint.h

@@ -0,0 +1,42 @@
+// Copyright (c) 2016-2019 Anyar, Inc.
+// 
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+// http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "ascent/modular/Module.h"
+#include "ascent/integrators_modular/ModularIntegrators.h"
+
+namespace asc
+{
+ namespace modular
+ {
+ template <class value_t>
+ struct MidpointProp : public Propagator<value_t>
+ {
+ void operator()(State& state, const value_t dt) override
+ {
+ if (state.memory.empty())
+ {
+ state.memory.resize(1);
+ state.memory[0] = 0.0;
+ }
+ auto& xd0 = state.memory[0];
+
+ auto& xd = *state.xd;
+ *state.x += 0.5 * dt * (xd0 + xd);
+ xd0 = xd;
+ }
+ };
+ }
+}

include/ascent/integrators_modular/RK2.h

@@ -43,6 +43,8 @@ namespace asc
  case 1:
  x = x0 + dt * xd;
  break;
+ default:
+ break;
  }
  }
  };