From: David Wells <wellsd2@rpi.edu>
Date: Fri, 23 Feb 2018 20:06:29 +0000 (-0500)
Subject: Deprecate fixed_int_power.
X-Git-Tag: v9.0.0-rc1~389^2~1
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0bd7098169cbdf548811624fc11a68e7dfe93b40;p=dealii.git

Deprecate fixed_int_power.

We can use constexpr functions instead of recursive templates.
---

diff --git a/include/deal.II/base/utilities.h b/include/deal.II/base/utilities.h
index 717fd9662f..d6009340f5 100644
--- a/include/deal.II/base/utilities.h
+++ b/include/deal.II/base/utilities.h
@@ -302,9 +302,24 @@ namespace Utilities
    *
    * Use this class as in <code>fixed_int_power@<5,2@>::%value</code> to
    * compute 5<sup>2</sup>.
+   *
+   * @deprecated This template has been deprecated in favor of C++11's support
+   * for <code>constexpr</code> calculations, e.g., use
+   *
+   * @code
+   * constexpr int value = Utilities::pow(2, dim);
+   * @endcode
+   *
+   * instead of
+   *
+   * @code
+   * const int value = Utilities::fixed_int_power<2, dim>::value;
+   * @endcode
+   *
+   * to obtain a constant expression for <code>value</code>.
    */
   template <int a, int N>
-  struct fixed_int_power
+  struct DEAL_II_DEPRECATED fixed_int_power
   {
     static const int value = a *fixed_int_power<a,N-1>::value;
   };
@@ -312,13 +327,27 @@ namespace Utilities
   /**
    * Base case for the power operation with <code>N=0</code>, which gives the
    * result 1.
+   *
+   * @deprecated This template is deprecated: see the note in the general
+   * version of this template for more information.
    */
   template <int a>
-  struct fixed_int_power<a,0>
+  struct DEAL_II_DEPRECATED fixed_int_power<a,0>
   {
     static const int value = 1;
   };
 
+  /**
+   * A replacement for <code>std::pow</code> that allows compile-time
+   * calculations for constant expression arguments.
+   */
+  constexpr
+  unsigned int
+  pow(const unsigned int base, const unsigned int iexp)
+  {
+    return iexp == 0 ? 1 : base*dealii::Utilities::pow(base, iexp - 1);
+  }
+
   /**
    * Optimized replacement for <tt>std::lower_bound</tt> for searching within
    * the range of column indices. Slashes execution time by approximately one
diff --git a/include/deal.II/matrix_free/cuda_fe_evaluation.h b/include/deal.II/matrix_free/cuda_fe_evaluation.h
index 3465d7fefb..27bfb8d513 100644
--- a/include/deal.II/matrix_free/cuda_fe_evaluation.h
+++ b/include/deal.II/matrix_free/cuda_fe_evaluation.h
@@ -76,10 +76,8 @@ namespace CUDAWrappers
     typedef typename MatrixFree<dim, Number>::Data  data_type;
     static const unsigned int dimension    =        dim;
     static const unsigned int n_components =        n_components_;
-    static const unsigned int n_q_points   =
-      Utilities::fixed_int_power<n_q_points_1d,dim>::value;
-    static const unsigned int tensor_dofs_per_cell =
-      Utilities::fixed_int_power<fe_degree+1,dim>::value;
+    static constexpr unsigned int n_q_points      = Utilities::pow(n_q_points_1d, dim);
+    static constexpr unsigned int tensor_dofs_per_cell = Utilities::pow(fe_degree + 1, dim);
 
     /**
      * Constructor.
diff --git a/include/deal.II/matrix_free/cuda_tensor_product_kernels.h b/include/deal.II/matrix_free/cuda_tensor_product_kernels.h
index b2452d9434..d9a3558570 100644
--- a/include/deal.II/matrix_free/cuda_tensor_product_kernels.h
+++ b/include/deal.II/matrix_free/cuda_tensor_product_kernels.h
@@ -64,10 +64,8 @@ namespace CUDAWrappers
     struct EvaluatorTensorProduct<evaluate_general, dim, fe_degree,
       n_q_points_1d, Number>
     {
-      static const unsigned int dofs_per_cell =
-        Utilities::fixed_int_power<fe_degree+1,dim>::value;
-      static const unsigned int n_q_points =
-        Utilities::fixed_int_power<n_q_points_1d,dim>::value;
+      static constexpr unsigned int dofs_per_cell = Utilities::pow(fe_degree + 1, dim);
+      static constexpr unsigned int n_q_points = Utilities::pow(n_q_points_1d, dim);
 
       __device__ EvaluatorTensorProduct();
 
diff --git a/include/deal.II/matrix_free/evaluation_kernels.h b/include/deal.II/matrix_free/evaluation_kernels.h
index 7f69067eb7..d299486286 100644
--- a/include/deal.II/matrix_free/evaluation_kernels.h
+++ b/include/deal.II/matrix_free/evaluation_kernels.h
@@ -783,12 +783,12 @@ namespace internal
       for (unsigned int q=basis_size_1; q!=0; --q)
         FEEvaluationImplBasisChange<variant,next_dim,basis_size_1,basis_size_2,n_components,Number,Number2>
         ::do_forward(transformation_matrix,
-                     values_in + (q-1)*Utilities::fixed_int_power<basis_size_1,dim-1>::value,
-                     my_scratch + (q-1)*Utilities::fixed_int_power<basis_size_2,dim-1>::value);
+                     values_in + (q-1)*Utilities::pow(basis_size_1, dim-1),
+                     my_scratch + (q-1)*Utilities::pow(basis_size_2, dim-1));
       EvaluatorTensorProduct<variant, dim, basis_size_1, basis_size_2,
                              Number,Number2> eval_val (transformation_matrix);
       const unsigned int n_inner_blocks = (dim > 1 && basis_size_2 < 10) ? basis_size_2 : 1;
-      const unsigned int n_blocks = Utilities::fixed_int_power<basis_size_2,dim-1>::value;
+      const unsigned int n_blocks = Utilities::pow(basis_size_2, dim-1);
       for (unsigned int ii=0; ii<n_blocks; ii+=n_inner_blocks)
         for (unsigned int c=0; c<n_components; ++c)
           {
@@ -803,8 +803,8 @@ namespace internal
       for (unsigned int q=0; q<basis_size_1; ++q)
         FEEvaluationImplBasisChange<variant,next_dim,basis_size_1,basis_size_2,n_components,Number,Number2>
         ::do_backward(transformation_matrix, false,
-                      my_scratch + q*Utilities::fixed_int_power<basis_size_2,dim-1>::value,
-                      values_out + q*Utilities::fixed_int_power<basis_size_1,dim-1>::value);
+                      my_scratch + q*Utilities::pow(basis_size_2, dim-1),
+                      values_out + q*Utilities::pow(basis_size_1, dim-1));
     }
   };
 
@@ -872,7 +872,7 @@ namespace internal
     eval(AlignedVector<Number>(),
          shape_info.shape_gradients_collocation_eo,
          shape_info.shape_hessians_collocation_eo);
-    constexpr unsigned int n_q_points = Utilities::fixed_int_power<fe_degree+1,dim>::value;
+    constexpr unsigned int n_q_points = Utilities::pow(fe_degree+1, dim);
 
     for (unsigned int c=0; c<n_components; c++)
       {
@@ -931,7 +931,7 @@ namespace internal
     eval(AlignedVector<Number>(),
          shape_info.shape_gradients_collocation_eo,
          shape_info.shape_hessians_collocation_eo);
-    constexpr unsigned int n_q_points = Utilities::fixed_int_power<fe_degree+1,dim>::value;
+    constexpr unsigned int n_q_points = Utilities::pow(fe_degree+1, dim);
 
     for (unsigned int c=0; c<n_components; c++)
       {
@@ -1019,7 +1019,7 @@ namespace internal
                       "of lower degree, so the evaluation results would be "
                       "wrong. Thus, this class does not permit the desired "
                       "operation."));
-    constexpr unsigned int n_q_points = Utilities::fixed_int_power<n_q_points_1d,dim>::value;
+    constexpr unsigned int n_q_points = Utilities::pow(n_q_points_1d, dim);
 
     for (unsigned int c=0; c<n_components; c++)
       {
@@ -1064,7 +1064,7 @@ namespace internal
                       "operation."));
     AssertDimension(shape_info.shape_gradients_collocation_eo.size(),
                     (n_q_points_1d+1)/2*n_q_points_1d);
-    constexpr unsigned int n_q_points = Utilities::fixed_int_power<n_q_points_1d,dim>::value;
+    constexpr unsigned int n_q_points = Utilities::pow(n_q_points_1d, dim);
 
     for (unsigned int c=0; c<n_components; c++)
       {
@@ -1134,11 +1134,11 @@ namespace internal
                  data.fe_degree+1, data.n_q_points_1d);
 
       const unsigned int size_deg = fe_degree > -1 ?
-                                    Utilities::fixed_int_power<fe_degree+1,dim-1>::value :
+                                    Utilities::pow(fe_degree+1, dim-1) :
                                     (dim > 1 ? Utilities::fixed_power<dim-1>(data.fe_degree+1) : 1);
 
       const unsigned int n_q_points = fe_degree > -1 ?
-                                      Utilities::fixed_int_power<n_q_points_1d,dim-1>::value : data.n_q_points_face;
+                                      Utilities::pow(n_q_points_1d, dim-1) : data.n_q_points_face;
 
       if (evaluate_grad == false)
         for (unsigned int c=0; c<n_components; ++c)
@@ -1254,7 +1254,7 @@ namespace internal
       Eval eval2(val2,grad2,val1,data.fe_degree+1, data.n_q_points_1d);
 
       const unsigned int size_deg = fe_degree > -1 ?
-                                    Utilities::fixed_int_power<fe_degree+1,dim-1>::value :
+                                    Utilities::pow(fe_degree+1, dim-1) :
                                     (dim > 1 ? Utilities::fixed_power<dim-1>(data.fe_degree+1) : 1);
 
       const unsigned int n_q_points = fe_degree > -1 ?
diff --git a/include/deal.II/matrix_free/fe_evaluation.h b/include/deal.II/matrix_free/fe_evaluation.h
index adc1247592..d4e83961fb 100644
--- a/include/deal.II/matrix_free/fe_evaluation.h
+++ b/include/deal.II/matrix_free/fe_evaluation.h
@@ -1912,8 +1912,8 @@ public:
   typedef typename BaseClass::gradient_type gradient_type;
   static constexpr unsigned int dimension     = dim;
   static constexpr unsigned int n_components  = n_components_;
-  static constexpr unsigned int static_n_q_points    = Utilities::fixed_int_power<n_q_points_1d,dim>::value;
-  static constexpr unsigned int static_dofs_per_component = Utilities::fixed_int_power<fe_degree+1,dim>::value;
+  static constexpr unsigned int static_n_q_points    = Utilities::pow(n_q_points_1d, dim);
+  static constexpr unsigned int static_dofs_per_component = Utilities::pow(fe_degree + 1, dim);
   static constexpr unsigned int tensor_dofs_per_cell = static_dofs_per_component *n_components;
   static constexpr unsigned int static_dofs_per_cell = static_dofs_per_component *n_components;
 
diff --git a/include/deal.II/matrix_free/operators.h b/include/deal.II/matrix_free/operators.h
index 88e0bbd0fb..ced0beb93e 100644
--- a/include/deal.II/matrix_free/operators.h
+++ b/include/deal.II/matrix_free/operators.h
@@ -851,7 +851,7 @@ namespace MatrixFreeOperators
   CellwiseInverseMassMatrix<dim,fe_degree,n_components,Number>
   ::fill_inverse_JxW_values(AlignedVector<VectorizedArray<Number> > &inverse_jxw) const
   {
-    const unsigned int dofs_per_cell = Utilities::fixed_int_power<fe_degree+1,dim>::value;
+    constexpr unsigned int dofs_per_cell = Utilities::pow(fe_degree + 1, dim);
     Assert(inverse_jxw.size() > 0 &&
            inverse_jxw.size() % dofs_per_cell == 0,
            ExcMessage("Expected diagonal to be a multiple of scalar dof per cells"));
@@ -883,7 +883,7 @@ namespace MatrixFreeOperators
           const VectorizedArray<Number> *in_array,
           VectorizedArray<Number>       *out_array) const
   {
-    const unsigned int dofs_per_cell = Utilities::fixed_int_power<fe_degree+1,dim>::value;
+    constexpr unsigned int dofs_per_cell = Utilities::pow(fe_degree + 1, dim);
     Assert(inverse_coefficients.size() > 0 &&
            inverse_coefficients.size() % dofs_per_cell == 0,
            ExcMessage("Expected diagonal to be a multiple of scalar dof per cells"));
diff --git a/include/deal.II/matrix_free/tensor_product_kernels.h b/include/deal.II/matrix_free/tensor_product_kernels.h
index 91b3f21bc0..cae328832f 100644
--- a/include/deal.II/matrix_free/tensor_product_kernels.h
+++ b/include/deal.II/matrix_free/tensor_product_kernels.h
@@ -113,8 +113,8 @@ namespace internal
   template <int dim, int n_rows, int n_columns, typename Number, typename Number2>
   struct EvaluatorTensorProduct<evaluate_general,dim,n_rows,n_columns,Number,Number2>
   {
-    static const unsigned int n_rows_of_product = Utilities::fixed_int_power<n_rows,dim>::value;
-    static const unsigned int n_columns_of_product = Utilities::fixed_int_power<n_columns,dim>::value;
+    static constexpr unsigned int n_rows_of_product = Utilities::pow(n_rows, dim);
+    static constexpr unsigned int n_columns_of_product = Utilities::pow(n_columns, dim);
 
     /**
      * Empty constructor. Does nothing. Be careful when using 'values' and
@@ -298,9 +298,9 @@ namespace internal
     constexpr int mm     = contract_over_rows ? n_rows : n_columns,
                   nn     = contract_over_rows ? n_columns : n_rows;
 
-    constexpr int stride    = Utilities::fixed_int_power<n_columns,direction>::value;
+    constexpr int stride    = Utilities::pow(n_columns, direction);
     constexpr int n_blocks1 = one_line ? 1 : stride;
-    constexpr int n_blocks2 = Utilities::fixed_int_power<n_rows,(direction>=dim)?0:(dim-direction-1)>::value;
+    constexpr int n_blocks2 = Utilities::pow(n_rows, (direction>=dim) ? 0 : (dim-direction-1));
 
     for (int i2=0; i2<n_blocks2; ++i2)
       {
@@ -365,8 +365,8 @@ namespace internal
     constexpr int n_blocks2 = dim > 2 ? n_rows : 1;
 
     AssertIndexRange (face_direction, dim);
-    constexpr int stride = Utilities::fixed_int_power<n_rows,face_direction>::value;
-    constexpr int out_stride = Utilities::fixed_int_power<n_rows,dim-1>::value;
+    constexpr int stride = Utilities::pow(n_rows, face_direction);
+    constexpr int out_stride = Utilities::pow(n_rows, dim-1);
     const Number *DEAL_II_RESTRICT shape_values = this->shape_values;
 
     for (int i2=0; i2<n_blocks2; ++i2)
@@ -816,8 +816,8 @@ namespace internal
   template <int dim, int n_rows, int n_columns, typename Number, typename Number2>
   struct EvaluatorTensorProduct<evaluate_symmetric,dim,n_rows,n_columns,Number,Number2>
   {
-    static const unsigned int n_rows_of_product = Utilities::fixed_int_power<n_rows,dim>::value;
-    static const unsigned int n_columns_of_product = Utilities::fixed_int_power<n_columns,dim>::value;
+    static constexpr unsigned int n_rows_of_product = Utilities::pow(n_rows, dim);
+    static constexpr unsigned int n_columns_of_product = Utilities::pow(n_columns, dim);
 
     /**
      * Constructor, taking the data from ShapeInfo
@@ -900,9 +900,9 @@ namespace internal
     constexpr int n_cols = nn / 2;
     constexpr int mid    = mm / 2;
 
-    constexpr int stride    = Utilities::fixed_int_power<n_columns,direction>::value;
+    constexpr int stride    = Utilities::pow(n_columns, direction);
     constexpr int n_blocks1 = stride;
-    constexpr int n_blocks2 = Utilities::fixed_int_power<n_rows,(direction>=dim)?0:(dim-direction-1)>::value;
+    constexpr int n_blocks2 = Utilities::pow(n_rows, (direction>=dim) ? 0 : (dim-direction-1));
 
     for (int i2=0; i2<n_blocks2; ++i2)
       {
@@ -1078,9 +1078,9 @@ namespace internal
     constexpr int n_cols = nn / 2;
     constexpr int mid    = mm / 2;
 
-    constexpr int stride    = Utilities::fixed_int_power<n_columns,direction>::value;
+    constexpr int stride    = Utilities::pow(n_columns, direction);
     constexpr int n_blocks1 = stride;
-    constexpr int n_blocks2 = Utilities::fixed_int_power<n_rows,(direction>=dim)?0:(dim-direction-1)>::value;
+    constexpr int n_blocks2 = Utilities::pow(n_rows, (direction>=dim) ? 0 : (dim-direction-1));
 
     for (int i2=0; i2<n_blocks2; ++i2)
       {
@@ -1203,9 +1203,9 @@ namespace internal
     constexpr int n_cols = nn / 2;
     constexpr int mid    = mm / 2;
 
-    constexpr int stride    = Utilities::fixed_int_power<n_columns,direction>::value;
+    constexpr int stride    = Utilities::pow(n_columns, direction);
     constexpr int n_blocks1 = stride;
-    constexpr int n_blocks2 = Utilities::fixed_int_power<n_rows,(direction>=dim)?0:(dim-direction-1)>::value;
+    constexpr int n_blocks2 = Utilities::pow(n_rows, (direction>=dim) ? 0 : (dim-direction-1));
 
     for (int i2=0; i2<n_blocks2; ++i2)
       {
@@ -1357,8 +1357,8 @@ namespace internal
   template <int dim, int n_rows, int n_columns, typename Number, typename Number2>
   struct EvaluatorTensorProduct<evaluate_evenodd,dim,n_rows,n_columns,Number,Number2>
   {
-    static const unsigned int n_rows_of_product = Utilities::fixed_int_power<n_rows,dim>::value;
-    static const unsigned int n_columns_of_product = Utilities::fixed_int_power<n_columns,dim>::value;
+    static constexpr unsigned int n_rows_of_product = Utilities::pow(n_rows, dim);
+    static constexpr unsigned int n_columns_of_product = Utilities::pow(n_columns, dim);
 
     /**
      * Empty constructor. Does nothing. Be careful when using 'values' and
@@ -1531,9 +1531,9 @@ namespace internal
     constexpr int n_cols = nn / 2;
     constexpr int mid    = mm / 2;
 
-    constexpr int stride    = Utilities::fixed_int_power<n_columns,direction>::value;
+    constexpr int stride    = Utilities::pow(n_columns, direction);
     constexpr int n_blocks1 = one_line ? 1 : stride;
-    constexpr int n_blocks2 = Utilities::fixed_int_power<n_rows,(direction>=dim)?0:(dim-direction-1)>::value;
+    constexpr int n_blocks2 = Utilities::pow(n_rows, (direction>=dim) ? 0 : (dim-direction-1));
 
     constexpr int offset = (n_columns+1)/2;
 
@@ -1722,8 +1722,8 @@ namespace internal
   template <int dim, int n_rows, int n_columns, typename Number, typename Number2>
   struct EvaluatorTensorProduct<evaluate_symmetric_hierarchical,dim,n_rows,n_columns,Number,Number2>
   {
-    static const unsigned int n_rows_of_product = Utilities::fixed_int_power<n_rows,dim>::value;
-    static const unsigned int n_columns_of_product = Utilities::fixed_int_power<n_columns,dim>::value;
+    static constexpr unsigned int n_rows_of_product = Utilities::pow(n_rows, dim);
+    static constexpr unsigned int n_columns_of_product = Utilities::pow(n_columns, dim);
 
     /**
      * Empty constructor. Does nothing. Be careful when using 'values' and
@@ -1886,9 +1886,9 @@ namespace internal
     constexpr int n_cols = nn / 2;
     constexpr int mid    = mm / 2;
 
-    constexpr int stride    = Utilities::fixed_int_power<n_columns,direction>::value;
+    constexpr int stride    = Utilities::pow(n_columns, direction);
     constexpr int n_blocks1 = one_line ? 1 : stride;
-    constexpr int n_blocks2 = Utilities::fixed_int_power<n_rows,(direction>=dim)?0:(dim-direction-1)>::value;
+    constexpr int n_blocks2 = Utilities::pow(n_rows, (direction>=dim) ? 0 : (dim-direction-1));
 
     // this code may look very inefficient at first sight due to the many
     // different cases with if's at the innermost loop part, but all of the