Constant.h

// Copyright (C) 2019-2023 Chris Richardson, Michal Habera and Garth N.
// Wells
//
// This file is part of DOLFINx (https://www.fenicsproject.org)
//
// SPDX-License-Identifier:    LGPL-3.0-or-later
 
#pragma once
 
#include "dolfinx/common/types.h"
#include <span>
#include <vector>
 
namespace dolfinx::fem
{
 
template <dolfinx::scalar T>
class Constant
{
public:
  using value_type = T;
 
  explicit Constant(value_type c) : value({c}) {}
 
  explicit Constant(std::span<const value_type> c)
      : Constant(c, std::vector<std::size_t>{c.size()})
  {
  }
 
  Constant(std::span<const value_type> c, std::span<const std::size_t> shape)
      : value(c.begin(), c.end()), shape(shape.begin(), shape.end())
  {
  }
 
  std::vector<value_type> value;
 
  std::vector<std::size_t> shape;
};
} // namespace dolfinx::fem