Theano.tensor.round函数学习，同时解决输出Elemwise{xxx,no_inplace}.0的问题

1. 出现Elemwise{xxx,no_inplace}.0

  这是因为没有定义theano.function所致，参考下面错误示范：

y = np.random.normal(size=(2,2))

z1 = T.round(y, mode='half_to_even')

print(z1)

# 输 出

Elemwise{round_half_to_even,no_inplace}.0

​正确操作如下：

x = T.dmatrix('x')

y = np.random.normal(size=(2,2))

z = T.round(x, mode='half_to_even')

f = function([x], z)

print(f(y))

# 输 出

[[ 0.,  1.],

[-1., -1.]]

2. tensor.round(a, mode='half_to_even')函数学习

  其实就是对a近似，离哪个整数值近就近似成那个值，有2种模式(我的theano版本默认为half_to_even)，具体区别见下面代码:

# -*- coding:utf-8 -*-

# Theano learning

# 文档位置：http://deeplearning.net/software/theano/library/tensor/basic.html?highlight=round#theano.tensor.round

import theano

import numpy as np

import theano.tensor as T

from theano import function

# version 1.0.4

if __name__ == '__main__':

    """

    theano.tensor.round(a, mode='half_to_even')

    mode='half_to_even'(default) or 'half_away_from_zero'

    """

    x = T.dmatrix('x')

    y = np.random.normal(size=(2,2))

    z1 = T.round(x, mode='half_to_even')

    z2 = T.round(x, mode='half_away_from_zero')

    f1 = function([x], z1)

    f2 = function([x], z2)

    print(y)

    print(f1(y))

    print(f2(y))

    # 输 出

    # 试了好几个输入，可以看出2种模式近似几乎没区别，只有在近似到0时会出现-0这样

    [[-0.06255656 -0.44239336]

 	[-2.25829238 -0.23422771]]

	[[ 0.  0.]

	 [-2.  0.]]

	[[-0. -0.]

	 [-2. -0.]]