add API:Tensor.item(*args) and API:np.array(Tensor)

[zhwesky2010]

PR types

New features

PR changes

APIs

Describe

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1. Add API: Tensor.item(*args) to convert one element of Tensor to a Python scalar and return to user.

import paddle

x = paddle.to_tensor(1)
print(x.item())             #1
print(type(x.item()))      #<class 'int'>

x = paddle.to_tensor(1.0)
print(x.item())             #1.0
print(type(x.item()))      #<class 'float'>

x = paddle.to_tensor(True)
print(x.item())             #True
print(type(x.item()))       #<class 'bool'>

x = paddle.to_tensor(1+1j)
print(x.item())             #(1+1j)
print(type(x.item()))       #<class 'complex'>

x = paddle.to_tensor([[1.111111, 2.222222, 3.333333]])
print(x.item(2))            #3.333333
print(x.item(0, 2))         #3.333333

x = paddle.to_tensor([1, 2])
x.item()   #ValueError: only one element tensor can be converted to Python scalars when no input coordinates.

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2. Fix API: np.array(Tensor) to convert the Tensor to numpy.ndarray.

import paddle
import numpy as np

x = paddle.randn([2, 2])
x_array = np.array(x)

print(type(x_array))            #<class 'numpy.ndarray'>
print(x_array.shape)            #(2, 2)

[paddle-bot-old]

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[XiaoguangHu01]

LGTM