get_partial_matmul_right Function

  function get_partial_matmul_right(this, upstream_grad) result(output)
    !! Get partial derivative with respect to right operand of matmul
    implicit none
    class(array_type), intent(inout) :: this
    type(array_type), intent(in) :: upstream_grad
    type(array_type) :: output

    logical :: left_is_temporary_local
    type(array_type), pointer :: ptr

    left_is_temporary_local = this%left_operand%is_temporary
    this%left_operand%is_temporary = .false.
    if(size(this%left_operand%shape).eq.2)then
       if(this%is_forward)then
          ptr => matmul(this%left_operand, upstream_grad)
       else
          ptr => matmul(transpose(this%left_operand), upstream_grad)
       end if
    elseif(size(upstream_grad%shape).eq.2)then
       if(this%is_forward)then
          ptr => matmul(this%left_operand, upstream_grad)
       else
          ptr => matmul(this%left_operand, transpose(upstream_grad))
       end if
    else
       ptr => this%left_operand .outer. upstream_grad
    end if
    this%left_operand%is_temporary = left_is_temporary_local
    call output%assign_and_deallocate_source(ptr)

  end function get_partial_matmul_right