add framework for volume

elements/src/CMakeLists.txt

@@ -46,8 +46,10 @@ add_library(${PROJECT_NAME}-elements
             integrator/IntegrateTrait.cc
             integrator/IntegratorBase.cc
             integrator/IsoparametricIntegrator.cc
+            integrator/VolumeTrait.cc
             integrator/integrate.cc
             integrator/integrate_shape.cc
+            integrator/volume.cc
             materialmodels/AutomaticStressTrait.cc
             materialmodels/AutomaticTangentMatrixTrait.cc
             materialmodels/ComputeEnergyTrait.cc

elements/src/include/ae108/elements/integrator/IsoparametricIntegrator.h

@@ -19,6 +19,7 @@
 #include "ae108/elements/integrator/IntegrateShapeTrait.h"
 #include "ae108/elements/integrator/IntegrateTrait.h"
 #include "ae108/elements/integrator/IntegratorBase.h"
+#include "ae108/elements/integrator/VolumeTrait.h"
 #include "ae108/elements/quadrature/integrate.h"
 #include "ae108/elements/tensor/Tensor.h"
 #include "ae108/elements/tensor/as_matrix_of_rows.h"
@@ -124,6 +125,17 @@ struct IntegrateShapeTrait<
   }
 };
 
+template <class Shape_, class Quadrature_, class ValueType_, class RealType_>
+struct VolumeTrait<
+    IsoparametricIntegrator<Shape_, Quadrature_, ValueType_, RealType_>> {
+  template <class Integrator>
+  auto operator()(const Integrator &integrator) const noexcept {
+    return quadrature::integrate<Quadrature_>(
+        [](auto &&, auto &&, const auto &post) { return post; },
+        typename Integrator::real_type{0.}, integrator.post());
+  }
+};
+
 } // namespace integrator
 } // namespace elements
 } // namespace ae108

elements/src/include/ae108/elements/integrator/VolumeTrait.h

+// © 2022 ETH Zurich, Mechanics and Materials Lab
+//
+// 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
+
+namespace ae108 {
+namespace elements {
+namespace integrator {
+
+template <class Integrator> struct VolumeTrait;
+
+} // namespace integrator
+} // namespace elements
+} // namespace ae108
\ No newline at end of file

elements/src/include/ae108/elements/integrator/volume.h

+// © 2022 ETH Zurich, Mechanics and Materials Lab
+//
+// 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 "ae108/elements/integrator/VolumeTrait.h"
+
+namespace ae108 {
+namespace elements {
+namespace integrator {
+
+/**
+ * @brief Integrates the constant function 1.
+ */
+template <class Integrator>
+typename Integrator::real_type volume(const Integrator &integrator) noexcept {
+  return VolumeTrait<Integrator>().template operator()(integrator);
+}
+
+} // namespace integrator
+} // namespace elements
+} // namespace ae108
\ No newline at end of file

elements/src/integrator/VolumeTrait.cc

+// © 2022 ETH Zurich, Mechanics and Materials Lab
+//
+// 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.
+
+#include "ae108/elements/integrator/VolumeTrait.h"
\ No newline at end of file

elements/src/integrator/volume.cc

+// © 2022 ETH Zurich, Mechanics and Materials Lab
+//
+// 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.
+
+#include "ae108/elements/integrator/volume.h"
\ No newline at end of file

elements/test/integrator/IsoperimetricIntegrator_Test.cc

@@ -16,6 +16,7 @@
 #include "ae108/elements/integrator/IsoparametricIntegrator.h"
 #include "ae108/elements/integrator/integrate.h"
 #include "ae108/elements/integrator/integrate_shape.h"
+#include "ae108/elements/integrator/volume.h"
 #include "ae108/elements/quadrature/Quadrature.h"
 #include "ae108/elements/shape/Seg2.h"
 #include <gmock/gmock.h>
@@ -56,8 +57,8 @@ TEST_F(IsoperimetricIntegrator_Test, post_transform_is_correct) {
   EXPECT_THAT(post, ElementsAre(DoubleEq(.5)));
 }
 
-TEST_F(IsoperimetricIntegrator_Test, computing_volume_works) {
-  const auto result = integrate<Integrator>(
+TEST_F(IsoperimetricIntegrator_Test, computing_volume_via_integration_works) {
+  const auto result = integrate(
       integrator,
       [](const Integrator::size_type &, const Integrator::Point<1> &,
          const Integrator::PreTransform &) { return 1.; },
@@ -66,9 +67,14 @@ TEST_F(IsoperimetricIntegrator_Test, computing_volume_works) {
   EXPECT_THAT(result, DoubleEq(1.));
 }
 
+TEST_F(IsoperimetricIntegrator_Test, computing_volume_works) {
+  const auto result = volume(integrator);
+  EXPECT_THAT(result, DoubleEq(1.));
+}
+
 TEST_F(IsoperimetricIntegrator_Test, integrating_shape_works) {
   const auto factor = std::sqrt(2.);
-  const auto result = integrate_shape<Integrator>(
+  const auto result = integrate_shape(
       integrator,
       [factor](auto &&, const auto &point) {
         return point[0] + factor * point[1];