columns_dot_self.hpp

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#ifndef STAN_MATH_OPENCL_REV_COLUMNS_DOT_SELF_HPP
#define STAN_MATH_OPENCL_REV_COLUMNS_DOT_SELF_HPP
#ifdef STAN_OPENCL
 
#include <stan/math/opencl/kernel_generator.hpp>
#include <stan/math/rev/core.hpp>
#include <stan/math/rev/fun/adjoint_of.hpp>
#include <stan/math/rev/fun/value_of.hpp>
#include <stan/math/prim/fun/size_zero.hpp>
 
namespace stan {
namespace math {
 
template <typename T,
          require_all_kernel_expressions_and_none_scalar_t<T>* = nullptr>
inline var_value<matrix_cl<double>> columns_dot_self(const var_value<T>& v) {
  if (size_zero(v)) {
    return var_value<matrix_cl<double>>(constant(0.0, 1, v.cols()));
  }
 
  return make_callback_var(
      columns_dot_self(v.val()),
      [v](const vari_value<matrix_cl<double>>& res) mutable {
        v.adj()
            += elt_multiply(colwise_broadcast(res.adj() * 2.0), value_of(v));
      });
}
 
}  // namespace math
}  // namespace stan
 
#endif
#endif