.. algorithm::

.. summary::

.. relatedalgorithms::

.. properties::

Description
-----------

A NOT operation will be conducted on the input masking workspace
(SpecialWorkspace2D).

Output
######

A SpecialWorkspace2D with the same dimension and geometry as the input
two SpecialWorkspace2D.


Usage
-----

**Example - invert a POWGEN mask:**

.. testcode:: ExInvertPG3

  # Load data
  maskws = LoadMask(Instrument="POWGEN_Definition_2015-08-01.xml",
                    InputFile="Mask-PG3-19884.xml")

  # Check source mask workspace
  nummasked = 0
  for i in range(maskws.getNumberHistograms()):
    if maskws.readY(i)[0] > 0.5:
      nummasked += 1

  # Invert mask
  invmaskws = InvertMask(InputWorkspace=maskws)

  # Check target mask workspace
  nummasked2 = 0
  for i in range(invmaskws.getNumberHistograms()):
    if invmaskws.readY(i)[0] > 0.5:
      nummasked2 += 1

  # Print out
  print("Number of histogram:  {}".format(maskws.getNumberHistograms()))
  print("Source Mask workspace # Detectors masked =  {}".format(nummasked))
  print("Source Mask workspace # Detectors masked =  {}".format(nummasked2))

Output:

.. testoutput:: ExInvertPG3

  Number of histogram:  33418
  Source Mask workspace # Detectors masked =  82
  Source Mask workspace # Detectors masked =  33336

.. categories::

.. sourcelink::