nancumsum

Compute the cumulative sum of matrices, specifying the treatment of NaNs.

Description

nancumsum: Cumulative sum of a matrix, with user-specified treatment of NaNs.
      
Computes the cumulative sum of matrix A along dimension DIM, allowing the user to replace NaNs with zeros, to skip over them, or to reset on NaNs, maintaining NaNs as placeholders.
 
USAGE: B = nancumsum(A, DIM, NMODE)
 
ARGUMENTS:
 
A: Input matrix.
 
B: Output cumulative sum matrix, treating NaNs as determined by nmode.
 
DIM: B = nancumsum(A, DIM) returns the nan-cumulative sum of the elements
along the dimension of A specified by scalar DIM. For example,nancumsum(A,1) works down the columns, nancumsum(A,2) works across the rows. If DIM is not specified, it defaults to the first non-singleton dimension of A.
 
NMODE: specifies how NaNs should be treated. Acceptable values are:
1: REPLACE NaNs with zeros (default).
2: MAINTAIN NaNs as position holders in B. (Skip NaNs without reset.)
3: RESET sum on NaNs, replacing NaNs with zeros.
4: RESET sum on NaNs, maintaining NaNs as position holders.
  
See also: cumsum, nansum, nancumprod, nanmean, nanmedian, ...
(nancumprod is available from the FEX. Other nan* may require Toolboxes)

• MATLAB release: MATLAB 7.4 (R2007a)

[John D'Errico]

As you should expect from Brett, excellent in all respects.

[Urs (us) Schwarz]

a trouvaille of paramount importance to this community - offered by former CSSM senior brett shoelson; a function that should have been in ML stock for a long time.
needless to say that his clean coding fulfills all the criteria to be a five-star contender: concise h1, help text with meticulous examples, proper input and options error checking, and an interesting, vectorized engine.
us