From: Martin Kronbichler <martin.kronbichler@uni-a.de>
Date: Mon, 19 Jun 2023 16:58:34 +0000 (+0200)
Subject: Make FE_EVAL_FACTORY_DEGREE_MAX more robust
X-Git-Tag: v9.5.0-rc1~85^2~1
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f072c7f0a9f524a4572528dfff09a5addd4f90bc;p=dealii.git

Make FE_EVAL_FACTORY_DEGREE_MAX more robust
---

diff --git a/include/deal.II/matrix_free/evaluation_kernels.h b/include/deal.II/matrix_free/evaluation_kernels.h
index 0f083d655c..422c597c0a 100644
--- a/include/deal.II/matrix_free/evaluation_kernels.h
+++ b/include/deal.II/matrix_free/evaluation_kernels.h
@@ -5856,6 +5856,20 @@ namespace internal
     }
   };
 
+  /**
+   * This struct is used to implement
+   * FEEvaluation::fast_evaluation_supported() and
+   * FEFaceEvaluation::fast_evaluation_supported().
+   */
+  struct FastEvaluationSupported
+  {
+    template <int fe_degree, int n_q_points_1d>
+    static bool
+    run()
+    {
+      return fe_degree != -1;
+    }
+  };
 } // end of namespace internal
 
 
diff --git a/include/deal.II/matrix_free/evaluation_template_face_factory.templates.h b/include/deal.II/matrix_free/evaluation_template_face_factory.templates.h
index fa068963ba..e9c541136b 100644
--- a/include/deal.II/matrix_free/evaluation_template_face_factory.templates.h
+++ b/include/deal.II/matrix_free/evaluation_template_face_factory.templates.h
@@ -118,6 +118,21 @@ namespace internal
       fe_eval);
   }
 
+
+
+  // It is important that this file sits in the same compilation unit as the
+  // evaluate() and integrate() calls of this class, to ensure that all
+  // options choose the same code path when compiling FEFaceEvaluationFactory
+  // outside of deal.II.
+  template <int dim, typename Number>
+  bool
+  FEFaceEvaluationFactory<dim, Number>::fast_evaluation_supported(
+    const unsigned int given_degree,
+    const unsigned int n_q_points_1d)
+  {
+    return instantiation_helper_run<1, FastEvaluationSupported>(given_degree,
+                                                                n_q_points_1d);
+  }
 } // end of namespace internal
 
 DEAL_II_NAMESPACE_CLOSE
diff --git a/include/deal.II/matrix_free/evaluation_template_factory.h b/include/deal.II/matrix_free/evaluation_template_factory.h
index a179402e54..0d8e036c33 100644
--- a/include/deal.II/matrix_free/evaluation_template_factory.h
+++ b/include/deal.II/matrix_free/evaluation_template_factory.h
@@ -71,6 +71,10 @@ namespace internal
               const EvaluationFlags::EvaluationFlags integration_flag,
               Number *                               values_dofs,
               FEEvaluationData<dim, Number, true> &  fe_eval);
+
+    static bool
+    fast_evaluation_supported(const unsigned int given_degree,
+                              const unsigned int n_q_points_1d);
   };
 
 
diff --git a/include/deal.II/matrix_free/evaluation_template_factory.templates.h b/include/deal.II/matrix_free/evaluation_template_factory.templates.h
index bd0f37fda6..51b98ee4d0 100644
--- a/include/deal.II/matrix_free/evaluation_template_factory.templates.h
+++ b/include/deal.II/matrix_free/evaluation_template_factory.templates.h
@@ -29,18 +29,6 @@ DEAL_II_NAMESPACE_OPEN
 
 namespace internal
 {
-  struct FastEvaluationSupported
-  {
-    template <int fe_degree, int n_q_points_1d>
-    static bool
-    run()
-    {
-      return fe_degree != -1;
-    }
-  };
-
-
-
   template <int dim, typename Number>
   void
   FEEvaluationFactory<dim, Number>::evaluate(
@@ -81,6 +69,10 @@ namespace internal
 
 
 
+  // It is important that this file sits in the same compilation unit as the
+  // evaluate() and integrate() calls of this class, to ensure that all
+  // options choose the same code path when compiling FEFaceEvaluationFactory
+  // outside of deal.II.
   template <int dim, typename Number>
   bool
   FEEvaluationFactory<dim, Number>::fast_evaluation_supported(
diff --git a/include/deal.II/matrix_free/fe_evaluation.h b/include/deal.II/matrix_free/fe_evaluation.h
index a171bcda11..59b8f75c6b 100644
--- a/include/deal.II/matrix_free/fe_evaluation.h
+++ b/include/deal.II/matrix_free/fe_evaluation.h
@@ -1709,8 +1709,16 @@ protected:
  * setting the macro `FE_EVAL_FACTORY_DEGREE_MAX` to the desired integer and
  * instantiating the classes FEEvaluationFactory and FEFaceEvaluationFactory
  * (the latter for FEFaceEvaluation) creates paths to templated functions for
- * a possibly larger set of degrees. You can check if fast
- * evaluation/integration for a given degree/n_quadrature_points pair by calling
+ * a possibly larger set of degrees. This can both be set when configuring
+ * deal.II by passing the flag `-D FE_EVAL_FACTORY_DEGREE_MAX=8` (in case you
+ * want to compile all degrees up to eight; recommended setting) or by
+ * compiling `evaluation_template_factory.templates.h` and
+ * `evaluation_template_face_factory.templates.h` with the
+ * `FE_EVAL_FACTORY_DEGREE_MAX` overriden to the desired value. In the second
+ * option, symbols will be available twice, and it depends on your linker and
+ * dynamic library loader whether the user-specified setting takes
+ * precendence. You can check if fast evaluation/integration for a given
+ * degree/n_quadrature_points pair by calling
  * FEEvaluation::fast_evaluation_supported() or
  * FEFaceEvaluation::fast_evaluation_supported().
  *
@@ -9249,7 +9257,7 @@ FEFaceEvaluation<dim,
                             const unsigned int given_n_q_points_1d)
 {
   return fe_degree == -1 ?
-           internal::FEEvaluationFactory<dim, VectorizedArrayType>::
+           internal::FEFaceEvaluationFactory<dim, VectorizedArrayType>::
              fast_evaluation_supported(given_degree, given_n_q_points_1d) :
            true;
 }