# tensorplay.functional.ormqr

Source: https://www.tensorplay.cn/docs/generated/tensorplay.functional.ormqr.html

```python
tensorplay.functional.ormqr(input, tau, other, left=True, transpose=False, *, out=None) → Tensor
```

Computes the matrix-matrix multiplication of a product of Householder matrices with a general matrix.

Multiplies a $m \times n$ matrix C (given by other) with a matrix Q,
where Q is represented using Householder reflectors (input, tau).
See [Representation of Orthogonal or Unitary Matrices](https://www.netlib.org/lapack/lug/node128.html) for further details.

If left is True then op(Q) times C is computed, otherwise the result is C times op(Q).
When left is True, the implicit matrix Q has size $m \times m$.
It has size $n \times n$ otherwise.
If [transpose](/docs/generated/tensorplay.functional.transpose.html#tensorplay.functional.transpose) is True then op is the conjugate transpose operation, otherwise it’s a no-op.

Supports inputs of float, double, cfloat and cdouble dtypes.
Also supports batched inputs, and, if the input is batched, the output is batched with the same dimensions.

> **See also**
>
> tensorplay.geqrf() can be used to form the Householder representation (input, tau) of matrix Q from the QR decomposition.

> **Note**
>
> This function supports backward but it is only fast when (input, tau) do not require gradients and/or tau.size(-1) is very small. ``

Parameters:

- input ([Tensor](/docs/generated/tensorplay.Tensor.html#tensorplay.Tensor)) – tensor of shape (*, mn, k) where * is zero or more batch dimensions and mn equals to m or n depending on the left.

- tau ([Tensor](/docs/generated/tensorplay.Tensor.html#tensorplay.Tensor)) – tensor of shape (*, min(mn, k)) where * is zero or more batch dimensions.

- other ([Tensor](/docs/generated/tensorplay.Tensor.html#tensorplay.Tensor)) – tensor of shape (*, m, n) where * is zero or more batch dimensions.

- left ([bool](https://docs.python.org/3/builtins/functions.html#bool)) – controls the order of multiplication.

- transpose ([bool](https://docs.python.org/3/builtins/functions.html#bool)) – controls whether the matrix Q is conjugate transposed or not.

Keyword Arguments:

out ([Tensor](/docs/generated/tensorplay.Tensor.html#tensorplay.Tensor), optional) – the output Tensor. Ignored if None. Default: None.