blas.py 文件源码

def backward(ctx, grad_output):
        matrix, vector = ctx.saved_variables
        grad_add_vector = grad_matrix = grad_vector = None

        if ctx.needs_input_grad[0]:
            grad_add_vector = grad_output
            if ctx.alpha != 1:
                grad_add_vector = grad_add_vector.mul(ctx.alpha)

        if ctx.needs_input_grad[1]:
            grad_matrix = torch.ger(grad_output, vector)
            if ctx.beta != 1:
                grad_matrix *= ctx.beta

        if ctx.needs_input_grad[2]:
            grad_vector = torch.mv(matrix.t(), grad_output)
            if ctx.beta != 1:
                grad_vector *= ctx.beta

        return grad_add_vector, grad_matrix, grad_vector, None, None, None