Line data    Source code

       1           1 : // Distributed under the MIT License.
       2             : // See LICENSE.txt for details.
       3             : 
       4             : ///\file
       5             : /// Defines make_with_value
       6             : 
       7             : #pragma once
       8             : 
       9             : #include <array>
      10             : #include <complex>
      11             : #include <type_traits>
      12             : #include <vector>
      13             : 
      14             : #include "Utilities/Algorithm.hpp"
      15             : #include "Utilities/ErrorHandling/Assert.hpp"
      16             : #include "Utilities/ForceInline.hpp"
      17             : #include "Utilities/MakeArray.hpp"
      18             : 
      19             : /// \ingroup DataStructuresGroup
      20             : /// Implementations of make_with_value.
      21             : namespace MakeWithValueImpls {
      22             : /// Defines a method for determining the number of points represented
      23             : /// by an object.  This allows the object to appear as the input to
      24             : /// make_with_value.
      25             : ///
      26             : /// The MakeWithValueImpls::number_of_points convenience wrapper is
      27             : /// provided to simplify calling this.
      28             : template <typename T, typename = std::nullptr_t>
      29           1 : struct NumberOfPoints {
      30             :   /// The default implementation will produce a compile-time error.
      31           1 :   [[noreturn]] static SPECTRE_ALWAYS_INLINE size_t apply(const T& /*input*/) {
      32             :     static_assert(typename tmpl::has_type<T, std::false_type>::type{},
      33             :                   "Do not know how to obtain a size from this type.  Either "
      34             :                   "implement NumberOfPoints or specialize MakeWithValueImpl "
      35             :                   "for the type you are trying to create.");
      36             :   }
      37             : };
      38             : 
      39             : /// The number of points represented by an object.
      40             : template <typename T>
      41           1 : size_t number_of_points(const T& input) {
      42             :   return NumberOfPoints<T>::apply(input);
      43             : }
      44             : 
      45             : /// Defines a method for producing an object representing a given
      46             : /// number of points.
      47             : ///
      48             : /// Do not call these functions directly.  Use make_with_value
      49             : /// instead, which can take a size as its first argument.
      50             : template <typename R, typename = std::nullptr_t>
      51           1 : struct MakeWithSize {
      52             :   /// The default implementation will produce a compile-time error.
      53             :   /// In specializations, the \p value parameter need not be a template.
      54             :   template <typename T>
      55           1 :   [[noreturn]] static SPECTRE_ALWAYS_INLINE R apply(const size_t /*size*/,
      56             :                                                     const T& /*value*/) {
      57             :     static_assert(typename tmpl::has_type<R, std::false_type>::type{},
      58             :                   "Do not know how to create a sized object of this type.  "
      59             :                   "Either implement MakeWithSize or specialize "
      60             :                   "MakeWithValueImpl for the type you are trying to create.");
      61             :   }
      62             : };
      63             : 
      64             : template <typename R, typename T, typename = std::nullptr_t>
      65           0 : struct MakeWithValueImpl {
      66             :   /// The default implementation uses \ref number_of_points and MakeWithSize.
      67             :   template <typename ValueType>
      68           1 :   static SPECTRE_ALWAYS_INLINE R apply(const T& input, const ValueType value) {
      69             :     return MakeWithSize<R>::apply(number_of_points(input), value);
      70             :   }
      71             : };
      72             : }  // namespace MakeWithValueImpls
      73             : 
      74             : /// \ingroup DataStructuresGroup
      75             : /// \brief Given an object of type `T`, create an object of type `R` whose
      76             : /// elements are initialized to `value`.
      77             : ///
      78             : /// \details This function is useful in function templates in order to
      79             : /// initialize the return type of a function template with `value` for functions
      80             : /// that can be called either at a single grid-point or to fill a data structure
      81             : /// at the same set of grid-points as the `input`
      82             : 
      83             : /// \tparam ValueType The type of `value`. For most containers, this will be
      84             : /// `double`.
      85             : ///
      86             : /// \see MakeWithValueImpls, set_number_of_grid_points
      87             : template <typename R, typename T, typename ValueType>
      88           1 : SPECTRE_ALWAYS_INLINE std::remove_const_t<R> make_with_value(
      89             :     const T& input, const ValueType& value) {
      90             :   return MakeWithValueImpls::MakeWithValueImpl<std::remove_const_t<R>,
      91             :                                                T>::apply(input, value);
      92             : }
      93             : 
      94             : namespace MakeWithValueImpls {
      95             : template <>
      96           0 : struct NumberOfPoints<size_t> {
      97           0 :   static SPECTRE_ALWAYS_INLINE size_t apply(const size_t& input) {
      98             :     return input;
      99             :   }
     100             : };
     101             : 
     102             : /// \brief Returns a double initialized to `value` (`input` is ignored)
     103             : template <typename T>
     104           1 : struct MakeWithValueImpl<double, T> {
     105           0 :   static SPECTRE_ALWAYS_INLINE double apply(const T& /* input */,
     106             :                                             const double value) {
     107             :     return value;
     108             :   }
     109             : };
     110             : 
     111             : template <typename T>
     112             : struct MakeWithValueImpl<std::complex<double>, T> {
     113             :   static SPECTRE_ALWAYS_INLINE std::complex<double> apply(
     114             :       const T& /* input */, const std::complex<double> value) {
     115             :     return value;
     116             :   }
     117             : };
     118             : 
     119             : /// \brief Makes a `std::array`; each element of the `std::array`
     120             : /// must be `make_with_value`-creatable from a `InputType`.
     121             : template <size_t Size, typename T, typename InputType>
     122             : struct MakeWithValueImpl<std::array<T, Size>, InputType> {
     123             :   template <typename ValueType>
     124             :   static SPECTRE_ALWAYS_INLINE std::array<T, Size> apply(
     125             :       const InputType& input, const ValueType value) {
     126             :     return make_array<Size>(make_with_value<T>(input, value));
     127             :   }
     128             : };
     129             : 
     130             : template <size_t Size, typename T>
     131             : struct NumberOfPoints<std::array<T, Size>> {
     132             :   static SPECTRE_ALWAYS_INLINE size_t apply(const std::array<T, Size>& input) {
     133             :     static_assert(Size > 0);
     134             :     // size_t is interpreted as the number of points in other
     135             :     // contexts, but that doesn't make sense here.
     136             :     static_assert(not std::is_same_v<T, size_t>,
     137             :                   "Cannot get size from non-vector.");
     138             :     const size_t points = number_of_points(input[0]);
     139             :     ASSERT(
     140             :         alg::all_of(input,
     141             :                     [&](const T& t) { return number_of_points(t) == points; }),
     142             :         "Inconsistent number of points in array entries.");
     143             :     return points;
     144             :   }
     145             : };
     146             : 
     147             : template <typename T>
     148             : struct NumberOfPoints<std::vector<T>> {
     149             :   static SPECTRE_ALWAYS_INLINE size_t apply(const std::vector<T>& input) {
     150             :     // size_t is interpreted as the number of points in other
     151             :     // contexts, but that doesn't make sense here.
     152             :     static_assert(not std::is_same_v<T, size_t>,
     153             :                   "Cannot get number_of_points from non-vector.");
     154             :     ASSERT(not input.empty(),
     155             :            "Cannot get number of points from empty std::vector.");
     156             :     const size_t points = number_of_points(input[0]);
     157             :     ASSERT(
     158             :         alg::all_of(input,
     159             :                     [&](const T& t) { return number_of_points(t) == points; }),
     160             :         "Inconsistent number of points in vector entries.");
     161             :     return points;
     162             :   }
     163             : };
     164             : 
     165             : }  // namespace MakeWithValueImpls