lbfgs_optimizer.py 文件源码

def update_opt(self, loss, target, inputs, extra_inputs=None, gradients=None, *args, **kwargs):
        """
        :param loss: Symbolic expression for the loss function.
        :param target: A parameterized object to optimize over. It should implement methods of the
        :class:`rllab.core.paramerized.Parameterized` class.
        :param leq_constraint: A constraint provided as a tuple (f, epsilon), of the form f(*inputs) <= epsilon.
        :param inputs: A list of symbolic variables as inputs
        :param gradients: symbolic expressions for the gradients of trainable parameters of the target. By default
        this will be computed by calling theano.grad
        :return: No return value.
        """

        self._target = target

        def get_opt_output(gradients):
            if gradients is None:
                gradients = theano.grad(loss, target.get_params(trainable=True))
            flat_grad = flatten_tensor_variables(gradients)
            return [loss.astype('float64'), flat_grad.astype('float64')]

        if extra_inputs is None:
            extra_inputs = list()

        self._opt_fun = lazydict(
            f_loss=lambda: compile_function(inputs + extra_inputs, loss),
            f_opt=lambda: compile_function(
                inputs=inputs + extra_inputs,
                outputs=get_opt_output(gradients),
            )
        )