pad_or_truncate
===============

.. py:function:: t3toolbox.backend.linalg.pad_or_truncate(array, pad_width, mode='constant', **kwargs)

   .. code-block:: python

      def pad_or_truncate(
              array,
              pad_width,
              mode='constant',
              **kwargs
      ):


   Pad and/or truncate an array per axis, using signed ``(before, after)`` widths.

   ``pad_width`` has one ``(before, after)`` pair per axis (like :py:func:`numpy.pad`), but a
   **negative** width *removes* that many entries instead of adding them: positive pads (``mode``
   controls fill, default zeros), negative truncates. The two compose -- an axis can be truncated on
   one side and padded on the other.

   .. rubric:: Examples

   >>> import numpy as np
   >>> import t3toolbox.backend.linalg as linalg
   >>> a = np.arange(6).reshape(2, 3)
   >>> linalg.pad_or_truncate(a, [(1, 0), (0, 2)]).tolist()   # +1 row before, +2 cols after (zeros)
   [[0, 0, 0, 0, 0], [0, 1, 2, 0, 0], [3, 4, 5, 0, 0]]
   >>> linalg.pad_or_truncate(a, [(0, -1), (-1, 0)]).tolist()  # drop last row, drop first col
   [[1, 2]]