Python tf.linalg.LinearOperatorZeros用法及代码示例

LinearOperator 的作用类似于 [batch] 零矩阵。

继承自：LinearOperator，Module

用法

tf.linalg.LinearOperatorZeros(
    num_rows, num_columns=None, batch_shape=None, dtype=None, is_non_singular=False,
    is_self_adjoint=True, is_positive_definite=False, is_square=True,
    assert_proper_shapes=False, name='LinearOperatorZeros'
)

该运算符的作用类似于 [batch] 零矩阵 A ，对于某些 b >= 0 ，其形状为 [B1,...,Bb, N, M] 。第一个 b 索引索引批处理成员。对于每个批次索引 (i1,...,ib) , A[i1,...,ib,::] 是一个 N x M 矩阵。此矩阵A 未具体化，但为了广播此形状将是相关的。

LinearOperatorZeros 使用 num_rows 以及可选的 num_columns , batch_shape 和 dtype 参数进行初始化。如果 num_columns 是 None ，则此运算符将被初始化为方阵。如果 batch_shape 是 None ，则此运算符有效地传递所有参数。如果提供了batch_shape，则可能会发生广播，这需要进行复制。

# Create a 2 x 2 zero matrix.
operator = LinearOperatorZero(num_rows=2, dtype=tf.float32)

operator.to_dense()
==> [[0., 0.]
     [0., 0.]]

operator.shape
==> [2, 2]

operator.determinant()
==> 0.

x = ... Shape [2, 4] Tensor
operator.matmul(x)
==> Shape [2, 4] Tensor, same as x.

# Create a 2-batch of 2x2 zero matrices
operator = LinearOperatorZeros(num_rows=2, batch_shape=[2])
operator.to_dense()
==> [[[0., 0.]
      [0., 0.]],
     [[0., 0.]
      [0., 0.]]]

# Here, even though the operator has a batch shape, the input is the same as
# the output, so x can be passed through without a copy.  The operator is able
# to detect that no broadcast is necessary because both x and the operator
# have statically defined shape.
x = ... Shape [2, 2, 3]
operator.matmul(x)
==> Shape [2, 2, 3] Tensor, same as tf.zeros_like(x)

# Here the operator and x have different batch_shape, and are broadcast.
# This requires a copy, since the output is different size than the input.
x = ... Shape [1, 2, 3]
operator.matmul(x)
==> Shape [2, 2, 3] Tensor, equal to tf.zeros_like([x, x])

形状兼容性

该运算符作用于具有兼容形状的 [batch] 矩阵。 x 是与 matmul 和 solve 的形状兼容的批处理矩阵，如果

operator.shape = [B1,...,Bb] + [N, M],  with b >= 0
x.shape =   [C1,...,Cc] + [M, R],
and [C1,...,Cc] broadcasts with [B1,...,Bb] to [D1,...,Dd]

矩阵属性提示

此 LinearOperator 使用 is_X 形式的布尔标志初始化，用于 X = non_singular, self_adjoint, positive_definite, square 。它们具有以下含义：

• 如果 is_X == True ，调用者应该期望操作符具有属性 X 。这是一个应该实现的承诺，但不是运行时断言。例如，有限的浮点精度可能会导致违反这些承诺。
• 如果 is_X == False ，调用者应该期望操作符没有 X 。
• 如果is_X == None(默认)，调用者应该没有任何期望。