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Specifications and Common Mistakes

- Specifications and Common Mistakes:

- Misspellings or punctuation mistakes,incorrect formulas, abnormal display.

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mindspore.ops.MatMul

class mindspore.ops.MatMul(transpose_a=False, transpose_b=False)

Multiplies matrix a and matrix b.

$$$$

Output_{i j}=sum_{k=1}^{p} a_{i k} b_{k j}=a_{i 1} b_{1 j}+a_{i 2} b_{2 j}+cdots+a_{i p} b_{p j}, pin N

where the $i,j$ indicates the output of the i-th row and j-th column element.

Note

• If $N\ast M$ cannot be divided by 16, the performance will be poor in ascend environment.

• The dtype of inputs must be same.

• On Ascend, float64 doesn't be supported.

Parameters

• transpose_a (bool) – If True , a is transposed before multiplication. Default: False .

• transpose_b (bool) – If True , b is transposed before multiplication. Default: False .

Inputs:

• a (Tensor) - The first tensor to be multiplied. The shape of the tensor is $(N,C)$. If transpose_a is True , its shape must be $(C,N)$ after transpose.

• b (Tensor) - The second tensor to be multiplied. The shape of the tensor is $(C,M)$. If transpose_b is True , its shape must be $(M,C)$ after transpose.

Outputs:

Tensor, the shape of the output tensor is $(N,M)$.

Raises

• TypeError – If transpose_a or transpose_b is not a bool.

• TypeError – If the dtype of a and the dtype of b are not the same.

• ValueError – If the column of matrix dimensions of a is not equal to the row of matrix dimensions of b.

• ValueError – If length of shape of a or b is not equal to 2.

Supported Platforms:

Ascend GPU CPU

Examples

>>> import mindspore
>>> import numpy as np
>>> from mindspore import Tensor, ops
>>> a = Tensor(np.ones(shape=[1, 3]), mindspore.float32)
>>> b = Tensor(np.ones(shape=[3, 4]), mindspore.float32)
>>> matmul = ops.MatMul()
>>> output = matmul(a, b)
>>> print(output)
[[3. 3. 3. 3.]]