Description of slsum

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slsum

PURPOSE

SLSUM Compute the sum of values in subarrays

SYNOPSIS

function S = slsum(A, d)

DESCRIPTION

SLSUM Compute the sum of values in subarrays

 $ Syntax $
   - S = slsum(A) 
   - S = slsum(A, d)
   - S = slsum(A, [d1 d2 ... dk])

 $ Arguments $
   - A:        the input array
   - d:        the dimensions along which the sum is performed
   - S:        the resultant sum matrix

 $ Description $
   - S = slsum(A) sums up the values in column vectors of A. It is 
     equivalent to S = sum(A)

   - S = slsum(A, d) sums up the values along dimension d. It is 
     equivalent to S = sum(A, d)

   - S = slsum(A, [d1 d2 ... dk]) sums up the values along dimension
     d1, d2, ... dk.

 $ History $
   - Created by Dahua Lin on Nov 18th, 2005

CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

• slnorm SLNORM Compute the Lp-norms

SOURCE CODE

0001 function S = slsum(A, d)
0002 %SLSUM Compute the sum of values in subarrays
0003 %
0004 % $ Syntax $
0005 %   - S = slsum(A)
0006 %   - S = slsum(A, d)
0007 %   - S = slsum(A, [d1 d2 ... dk])
0008 %
0009 % $ Arguments $
0010 %   - A:        the input array
0011 %   - d:        the dimensions along which the sum is performed
0012 %   - S:        the resultant sum matrix
0013 %
0014 % $ Description $
0015 %   - S = slsum(A) sums up the values in column vectors of A. It is
0016 %     equivalent to S = sum(A)
0017 %
0018 %   - S = slsum(A, d) sums up the values along dimension d. It is
0019 %     equivalent to S = sum(A, d)
0020 %
0021 %   - S = slsum(A, [d1 d2 ... dk]) sums up the values along dimension
0022 %     d1, d2, ... dk.
0023 %
0024 % $ History $
0025 %   - Created by Dahua Lin on Nov 18th, 2005
0026 %
0027 
0028 %% parse and verify input arguments
0029 if nargin < 2 || isempty(d)
0030     d = 1;
0031 end
0032 
0033 %% compute
0034 if isscalar(d)
0035     S = sum(A, d);
0036 else
0037     k = length(d);
0038     S = A;
0039     for i = 1 : k
0040         S = sum(S, d(i));
0041     end
0042 end
0043 
0044

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