resize.hpp

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#ifndef STAN_MATH_PRIM_MAT_FUN_RESIZE_HPP
#define STAN_MATH_PRIM_MAT_FUN_RESIZE_HPP

#include <stan/math/prim/mat/fun/Eigen.hpp>
#include <vector>

namespace stan {
namespace math {
namespace {
template <typename T, int R, int C>
void resize(Eigen::Matrix<T, R, C>& x, const std::vector<int>& dims, int pos) {
  x.resize(dims[pos], dims[pos + 1]);
}

template <typename T>
void resize(T /*x*/, const std::vector<int>& /*dims*/, int /*pos*/) {
  // no-op
}

template <typename T>
void resize(std::vector<T>& x, const std::vector<int>& dims, int pos) {
  x.resize(dims[pos]);
  ++pos;
  if (pos >= static_cast<int>(dims.size()))
    return;  // skips lowest loop to scalar
  for (size_t i = 0; i < x.size(); ++i)
    resize(x[i], dims, pos);
}
}  // namespace

/**
 * Recursively resize the specified vector of vectors,
 * which must bottom out at scalar values, Eigen vectors
 * or Eigen matrices.
 *
 * @param x Array-like object to resize.
 * @param dims New dimensions.
 * @tparam T Type of object being resized.
 */
template <typename T>
inline void resize(T& x, std::vector<int> dims) {
  resize(x, dims, 0U);
}

}  // namespace math
}  // namespace stan
#endif