COLBREAKS is the jVarfun module of jLab.

 COLBREAKS  Insert NANs into discontinuties in a vector.
 
    O1=COLBREAKS(I1), where I1 is a column vector, inserts NANs into I1 at
    its discontinuities (and puts one at the end), for example:
 		
 	  COLBREAKS([2;2;2;3;3])=[2;2;2;NAN;3;3;NAN];
 
    [O1,O2,O3,...]=COLBREAKS(I1,I2,...), where I1,I2,... are all column 
    vectors of the same length, uses I1 as a reference for the other 
    vectors and inserts NANs into all the vectors at locations where I1 is 
    discontinous.
 	
    For instance, using station number for I1 will sort a column of CTD 
    data into a NAN-padded matrix.
 
    Note that for complex-valued input arrays, a complex-valued NAN, 
    NAN+SQRT(-1)*NAN, is used to indicate the break locations. 
 
    MAT2=COLBREAKS(MAT1), where MAT1 and MAT2 are matrices of the same 
    size, also works.  In this case the first column of MAT1 is used as the
    reference vector.
 
    COLBREAKS, COL2MAT, and MAT2COL together form a system for moving data
    with segments of nonuniform length rapidly back and forth between a 
    column format and a padded-matrix format. CTD or float data, for 
    instance, can be stored in the (usually much smaller) column format and
    converted into the matrix format upon loading.
   
    COLBREAKS(C1,C2,...); with no output arguments overwrites the original
    input variables.  
 
    See also COL2MAT, MAT2COL, COL2CELL, CELL2COL, ORBITBREAKS.
    _________________________________________________________________
    This is part of JLAB --- type 'help jlab' for more information 
    (C) 2000--2013 J.M. Lilly --- type 'help jlab_license' for details