Documentation>MATLAB API>MISC - vl_binsum

ACCUMULATOR = VL_BINSUM(ACCUMULATOR,VALUES,INDEXES) adds the elements of the array VALUES to the elements of the array ACCUMULATOR indexed by INDEXES. VALUES and INDEXES must have the same dimensions, and the elements of INDEXES must be valid indexes for the array ACCUMULATOR (except for null indexes, which are silently skipped). An application is the calculation of a histogram ACCUMULATOR, where INDEXES are the bin occurences and VALUES are the occurence weights.

VL_BINSUM(...,DIM) operates only along the specified dimension DIM. In this case, ACCUMULATOR, VALUES and INDEXES are array of the same dimensions, except for the dimension DIM of ACCUMULATOR, which may differ, and INDEXES is an array of subscripts of the DIM-th dimension of ACCUMULATOR. A typical application is the calculation of multiple histograms, where each histogram is a 1-dimensional slice of the array ACCUMULATOR along the dimension DIM.

VALUES can also be a scalar. In this case, the value of VALUES is summed to all the specified bins.

ACCUMULATOR and VALUES must have the same storage class. ACCUMULATOR, VALUES, and INDEXES can be either DOUBLE, SINGLE, UINT64, INT64, UINT32, INT32, UINT16, INT16, UINT8, INT8. Integer math uses modulo-2 arithmetic (most MATLAB functions saturate instead).


The following relations illustrate VL_BINSUM() behavior:

  VL_BINSUM([0 0],  1, 2) = [0 1]
  VL_BINSUM([1 7], -1, 1) = [0 7]
  VL_BINSUM(EYE(3), [1 1 1], [1 2 3], 1) = 2*EYE(3)

See also: VL_HELP().