function d= matpctile(x,p)
% MATPCTILE - Generates a row vector of the p-th perctile values in
% each column of array x.
% d = matpctile(x,p)
%
% For ABS data where x(range,time), passing it (x',1) will return
% the profiles corresponding to the 1%-ile values for all time at each
% range.
%
% Chris Sherwood, USGS
% June 3, 2004
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Use of this program is self described.
% Program written in Matlab v7.1.0 SP3
% Program ran on PC with Windows XP Professional OS.
%
% "Although this program has been used by the USGS, no warranty, 
% expressed or implied, is made by the USGS or the United States 
% Government as to the accuracy and functioning of the program 
% and related program material nor shall the fact of distribution 
% constitute any such warranty, and no responsibility is assumed 
% by the USGS in connection therewith."
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%

[nr,nc] = size(x);
z = sort(x); % ascending, by columns
zmin = z(:,1);
zmax = z(:,nc);
index = 100*cumsum(ones(nr,1))/nr;
d =  interp1(index,z,p);
