multiplex
paddle.fluid.layers.
multiplex
(inputs, index)[源代码]
根据给定的index参数,该OP从每个输入Tensor中选择特定行构造输出Tensor。
设该OP输入包含
个Tensor,其中 代表第i个输入Tensor, 处于区间 。
设该OP输出为
,其中 为输出的第i行,则输出满足:
示例:
- # 输入为4个shape为[4,4]的Tensor
- inputs = [[[0,0,3,4], [0,1,3,4], [0,2,4,4], [0,3,3,4]],
- [[1,0,3,4], [1,1,7,8], [1,2,4,2], [1,3,3,4]],
- [[2,0,3,4], [2,1,7,8], [2,2,4,2], [2,3,3,4]],
- [[3,0,3,4], [3,1,7,8], [3,2,4,2], [3,3,3,4]]]
- # index为shape为[4,1]的Tensor
- index = [[3],[0],[1],[2]]
- # 输出shape为[4,4]
- out = [[3,0,3,4] // out[0] = inputs[index[0]][0] = inputs[3][0] = [3,0,3,4]
- [0,1,3,4] // out[1] = inputs[index[1]][1] = inputs[0][1] = [0,1,3,4]
- [1,2,4,2] // out[2] = inputs[index[2]][2] = inputs[1][2] = [1,2,4,2]
- [2,3,3,4]] // out[3] = inputs[index[3]][3] = inputs[2][3] = [2,3,3,4]
- 参数:
- inputs (list) - 为输入Tensor列表,列表元素为数据类型为float32,float64,int32,int64的多维Tensor。所有输入Tensor的shape应相同,秩必须至少为2。
- index (Variable)- 用来选择输入Tensor中的某些行构建输出Tensor的索引,为数据类型为int32或int64、shape为[M, 1]的2-D Tensor,其中M为输入Tensor个数。
返回:进行Multiplex运算后的输出Tensor。
返回类型:Variable(Tensor)。
代码示例
- import paddle.fluid as fluid
- import numpy as np
- x1 = fluid.layers.data(name='x1', shape=[4], dtype='float32')
- x2 = fluid.layers.data(name='x2', shape=[4], dtype='float32')
- index = fluid.layers.data(name='index', shape=[1], dtype='int32')
- out = fluid.layers.multiplex(inputs=[x1, x2], index=index)
- exe = fluid.Executor(fluid.CPUPlace())
- exe.run(fluid.default_startup_program())
- img1 = np.array([[1, 2], [3, 4]]).astype(np.float32)
- img2 = np.array([[5, 6], [7, 8]]).astype(np.float32)
- index = np.array([[1], [0]]).astype(np.int32)
- res = exe.run(fluid.default_main_program(), feed={'x1':img1, 'x2':img2, 'index':index}, fetch_list=[out])
- print(res) # [array([[5., 6.], [3., 4.]], dtype=float32)]