mindspore.ops.svd

mindspore.ops.svd(a, full_matrices=False, compute_uv=True)[source]

Computes the singular value decompositions of one or more matrices.

If \(A\) is a matrix, the svd returns the singular values \(S\), the left singular vectors \(U\) and the right singular vectors \(V\). It meets:

\[A=U*diag(S)*V^{T}\]
Parameters

  • a (Tensor) – Tensor of the matrices to be decomposed. The shape should be \((*, M, N)\), the supported dtype are float32 and float64..

  • full_matrices (bool, optional) – If true, compute full-sized \(U\) and \(V\). If false, compute only the leading P singular vectors, with P is the minimum of M and N. Default: False.

  • compute_uv (bool, optional) – If true, compute the left and right singular vectors. If false, compute only the singular values. Default: True.

Returns

  • s (Tensor) - Singular values. The shape is \((*, P)\).

  • u (Tensor) - Left singular vectors. If compute_uv is False, u will not be returned. The shape is \((*, M, P)\). If full_matrices is True, the shape will be \((*, M, M)\).

  • v (Tensor) - Right singular vectors. If compute_uv is False, v will not be returned. The shape is \((*, N, P)\). If full_matrices is True, the shape will be \((*, N, N)\).

Raises

  • TypeError – If full_matrices or compute_uv is not the type of bool.

  • TypeError – If the rank of input less than 2.

  • TypeError – If the type of input is not one of the following dtype: float32, float64.

Supported Platforms:

GPU CPU

Examples

>>> import numpy as np
>>> from mindspore import Tensor, set_context
>>> from mindspore import ops
>>> set_context(device_target="CPU")
>>> a = Tensor(np.array([[1, 2], [-4, -5], [2, 1]]).astype(np.float32))
>>> s, u, v = ops.svd(a, full_matrices=True, compute_uv=True)
>>> print(s)
[7.0652843 1.040081 ]
>>> print(u)
[[ 0.30821905 -0.48819482 0.81649697]
 [-0.90613353  0.11070572 0.40824813]
 [ 0.2896955   0.8656849  0.4082479 ]]
>>> print(v)
[[ 0.63863593 0.769509  ]
 [ 0.769509  -0.63863593]]