th a field F such that S.F=[1;2;3;4].
 
    One use of <a href="catstruct.html">CATSTRUCT</a> is in concatentating output from multiple cores
    when using SPMD in the parallel computing toolbox. 
 
    SNEW=<a href="catstruct.html">CATSTRUCT</a>(S,INDEX) only concatenates those fields listed in INDEX.
    Here index is a list of numbers indicating the fields by the order in 
    which they appear, e.g., INDEX=1:10 concatenates the first 10 fields.
 
    Usage:  snew=<a href="catstruct.html">catstruct</a>(