Matrix Reductions
=================

.. highlight:: cpp



.. index:: gpu::meanStdDev


cv::gpu::meanStdDev
-------------------

`id=0.607789005794 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/gpu/gpu%3A%3AmeanStdDev>`__




.. cfunction:: void meanStdDev(const GpuMat\& mtx, Scalar\& mean, Scalar\& stddev)

    Computes mean value and standard deviation of matrix elements.





    
    :param mtx: Source matrix.  ``CV_8UC1``  matrices are supported for now. 
    
    
    :param mean: Mean value. 
    
    
    :param stddev: Standard deviation value. 
    
    
    
See also: 
:func:`meanStdDev`
.



.. index:: gpu::norm


cv::gpu::norm
-------------

`id=0.423726153071 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/gpu/gpu%3A%3Anorm>`__




.. cfunction:: double norm(const GpuMat\& src, int normType=NORM_L2)

    Returns norm of matrix (or of two matrices difference).





    
    :param src: Source matrix. Any matrices except 64F are supported. 
    
    
    :param normType: Norm type.  ``NORM_L1`` ,  ``NORM_L2``  and  ``NORM_INF``  are supported for now. 
    
    
    


.. cfunction:: double norm(const GpuMat\& src, int normType, GpuMat\& buf)





    
    * **src** Source matrix. Any matrices except 64F are supported. 
    
    
    * **normType** Norm type.  ``NORM_L1`` ,  ``NORM_L2``  and  ``NORM_INF``  are supported for now. 
    
    
    * **buf** Optional buffer to avoid extra memory allocations. It's resized automatically. 
    
    
    


.. cfunction:: double norm(const GpuMat\& src1, const GpuMat\& src2,
   int normType=NORM_L2)





    
    * **src1** First source matrix.  ``CV_8UC1``  matrices are supported for now. 
    
    
    * **src2** Second source matrix. Must have the same size and type as  ``src1`` 
    
    .
    
    * **normType** Norm type.  ``NORM_L1`` ,  ``NORM_L2``  and  ``NORM_INF``  are supported for now. 
    
    
    
See also: 
:func:`norm`
.



.. index:: gpu::sum


cv::gpu::sum
------------

`id=0.979123982078 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/gpu/gpu%3A%3Asum>`__




.. cfunction:: Scalar sum(const GpuMat\& src)



.. cfunction:: Scalar sum(const GpuMat\& src, GpuMat\& buf)

    Returns sum of matrix elements.





    
    :param src: Source image of any depth except  ``CV_64F`` . 
    
    
    :param buf: Optional buffer to avoid extra memory allocations. It's resized automatically. 
    
    
    
See also: 
:func:`sum`
.



.. index:: gpu::absSum


cv::gpu::absSum
---------------

`id=0.607738316178 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/gpu/gpu%3A%3AabsSum>`__




.. cfunction:: Scalar absSum(const GpuMat\& src)



.. cfunction:: Scalar absSum(const GpuMat\& src, GpuMat\& buf)

    Returns sum of matrix elements absolute values.





    
    :param src: Source image of any depth except  ``CV_64F`` . 
    
    
    :param buf: Optional buffer to avoid extra memory allocations. It's resized automatically. 
    
    
    

.. index:: gpu::sqrSum


cv::gpu::sqrSum
---------------

`id=0.470934615291 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/gpu/gpu%3A%3AsqrSum>`__




.. cfunction:: Scalar sqrSum(const GpuMat\& src)



.. cfunction:: Scalar sqrSum(const GpuMat\& src, GpuMat\& buf)

    Returns squared sum of matrix elements.





    
    :param src: Source image of any depth except  ``CV_64F`` . 
    
    
    :param buf: Optional buffer to avoid extra memory allocations. It's resized automatically. 
    
    
    

.. index:: gpu::minMax


cv::gpu::minMax
---------------

`id=0.0207742957447 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/gpu/gpu%3A%3AminMax>`__




.. cfunction:: void minMax(const GpuMat\& src, double* minVal,
   double* maxVal=0, const GpuMat\& mask=GpuMat())



.. cfunction:: void minMax(const GpuMat\& src, double* minVal, double* maxVal,
   const GpuMat\& mask, GpuMat\& buf)

    Finds global minimum and maximum matrix elements and returns their values.





    
    :param src: Single-channel source image. 
    
    
    :param minVal: Pointer to returned minimum value.  ``NULL``  if not required. 
    
    
    :param maxVal: Pointer to returned maximum value.  ``NULL``  if not required. 
    
    
    :param mask: Optional mask to select a sub-matrix. 
    
    
    :param buf: Optional buffer to avoid extra memory allocations. It's resized automatically. 
    
    
    
Function doesn't work with 
``CV_64F``
images on GPU with compute capability 
:math:`<`
1.3.
See also: 
:func:`minMaxLoc`
.



.. index:: gpu::minMaxLoc


cv::gpu::minMaxLoc
------------------

`id=0.985111829483 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/gpu/gpu%3A%3AminMaxLoc>`__




.. cfunction:: void minMaxLoc(const GpuMat\& src, double\* minVal, double* maxVal=0,
   Point* minLoc=0, Point* maxLoc=0,
   const GpuMat\& mask=GpuMat())



.. cfunction:: void minMaxLoc(const GpuMat\& src, double* minVal, double* maxVal,
   Point* minLoc, Point* maxLoc, const GpuMat\& mask,
   GpuMat\& valbuf, GpuMat\& locbuf)

    Finds global minimum and maximum matrix elements and returns their values with locations.





    
    :param src: Single-channel source image. 
    
    
    :param minVal: Pointer to returned minimum value.  ``NULL``  if not required. 
    
    
    :param maxVal: Pointer to returned maximum value.  ``NULL``  if not required. 
    
    
    :param minValLoc: Pointer to returned minimum location.  ``NULL``  if not required. 
    
    
    :param maxValLoc: Pointer to returned maximum location.  ``NULL``  if not required. 
    
    
    :param mask: Optional mask to select a sub-matrix. 
    
    
    :param valbuf: Optional values buffer to avoid extra memory allocations. It's resized automatically. 
    
    
    :param locbuf: Optional locations buffer to avoid extra memory allocations. It's resized automatically. 
    
    
    
Function doesn't work with 
``CV_64F``
images on GPU with compute capability 
:math:`<`
1.3.
See also: 
:func:`minMaxLoc`
.



.. index:: gpu::countNonZero


cv::gpu::countNonZero
---------------------

`id=0.904273321304 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/gpu/gpu%3A%3AcountNonZero>`__




.. cfunction:: int countNonZero(const GpuMat\& src)



.. cfunction:: int countNonZero(const GpuMat\& src, GpuMat\& buf)

    Counts non-zero matrix elements.





    
    :param src: Single-channel source image. 
    
    
    :param buf: Optional buffer to avoid extra memory allocations. It's resized automatically. 
    
    
    
Function doesn't work with 
``CV_64F``
images on GPU with compute capability 
:math:`<`
1.3.
See also: 
:func:`countNonZero`
.