# [GitHub] [incubator-mxnet] ckt624 commented on a change in pull request #15861: Numpy det and slogdet operator

```ckt624 commented on a change in pull request #15861: Numpy det and slogdet
operator
URL: https://github.com/apache/incubator-mxnet/pull/15861#discussion_r313730410

```
```
##########
File path: python/mxnet/_numpy_op_doc.py
##########
@@ -20,6 +20,129 @@
"""Doc placeholder for numpy ops with prefix _np."""

+def _np_linalg_det(a):
+    """
+    det(a)
+
+    Compute the determinant of an array.
+
+    Parameters
+    ----------
+    a : (..., M, M) ndarray
+        Input array to compute determinants for.
+
+    Returns
+    -------
+    det : (...) ndarray
+        Determinant of `a`.
+
+    --------
+    slogdet : Another way to represent the determinant, more suitable
+    for large matrices where underflow/overflow may occur.
+
+    Notes
+    -----
+
+    Broadcasting rules apply, see the `numpy.linalg` documentation for
+    details.
+
+    The determinant is computed via LU factorization using the LAPACK
+    routine z/dgetrf.
+
+    Examples
+    --------
+    The determinant of a 2-D array [[a, b], [c, d]] is ad - bc:
+
+    >>> a = np.array([[1, 2], [3, 4]])
+    >>> np.linalg.det(a)
+    -2.0
+
+    Computing determinants for a stack of matrices:
+
+    >>> a = np.array([ [[1, 2], [3, 4]], [[1, 2], [2, 1]], [[1, 3], [3, 1]] ])
+    >>> a.shape
+    (3, 2, 2)
+    >>> np.linalg.det(a)
+    array([-2., -3., -8.])
+    """
+    pass
+
+
+def _np_linalg_slogdet(a):
+    """
+    slogdet(a)
+
+    Compute the sign and (natural) logarithm of the determinant of an array.
+
+    If an array has a very small or very large determinant, then a call to
+    `det` may overflow or underflow. This routine is more robust against such
+    issues, because it computes the logarithm of the determinant rather than
+    the determinant itself.
+
+    Parameters
+    ----------
+    a : (..., M, M) ndarray
+        Input array, has to be a square 2-D array.
+
+    Returns
+    -------
+    sign : (...) ndarray
+        A number representing the sign of the determinant. For a real matrix,
+        this is 1, 0, or -1. For a complex matrix, this is a complex number

Review comment:
fixed. Thx.

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.