struct JacobianStride {};  // Specializations below

#define SET_JACOBIAN_STRIDE(TYPE, VALUE) \
  template <>                            \
  struct JacobianStride<TYPE> {          \
    static constexpr int value = VALUE;  \
  }

SET_JACOBIAN_STRIDE(float, 1);
SET_JACOBIAN_STRIDE(double, 1);
SET_JACOBIAN_STRIDE(complex64, 2);
SET_JACOBIAN_STRIDE(complex128, 2);

template <typename X_T, typename Y_T, typename JAC_T>