%                                xstat.m
%  Scope:  This MATLAB program tests the following macros: rms, rss, rssxy, 
%          and statup. In addition, results from internal macros  mean and std
%          are recorded.
%  Usage:  xstat
%  Inputs:  - name of the input data file containing at least 3 columns
%           - name of the output file if selected, otherwise the data are
%             displayed on screen
%  Outputs: - input/output data stored on the selected output file or 
%             displayed on the screen
%  External Matlab macros used:  rms, rss, rssxy, statup.
%  Last update:  04/19/00
%  Copyright (C) 1996-00 by LL Consulting. All Rights Reserved.

clear

%  Enter the input data

disp('  ');
fname = input('Specify the name of the input data file -->  ','s');
disp('  ');
tt = load(fname);
[nrow,ncol] = size(tt);
if  ncol < 3
   error('XSTAT - Error : check the input data (less than 3 columns)');
end
x = tt(1:nrow,1);
xy = tt(1:nrow,1:2);
xyz = tt(1:nrow,1:3);

%  Determine the mean value for the array  x

xmean = mean(x);

%  Determine the standard deviation value for the array  x

xstd = std(x);

%  Determine the rms value for the array  x

xrms = rms(x);

%  Determine the rss value for the arrays  x and y

   xrssxy = rssxy(xy);

%  Determine the rss value for the arrays  x, y and z

   xrss = rss(xyz);

%  Determine the running mean (am), standard deviation (astd) and root mean
%  squares (arms) values for the array  x

np1 = 1;
am = 0.;
astd = 0.;
arms = 0.;
for k = 1:nrow
   xnp1 = x(k);
   [np1,am,astd,arms] = statup(np1,xnp1,am,astd,arms);
end

%  Save computed results into an external file if selected

yes = 'y';
answer = input('Do you want to save the results? (y/n)[n] --> ','s');
if (strcmp(answer,yes) == 1)
   disp('  ');
   f2 = input('Specify the output filename  -->  ','s');
   disp('  ');
else
   f2 = 1;      %  output to the screen
end

fprintf(f2,'\n   *****  Results for the first column of the input data \n');
fprintf(f2,'          by using the macros: mean, std, rms, statup (for \n');
fprintf(f2,'          running values) \n\n');
fprintf(f2,'mean(x) =  %15.7f\n',xmean);
fprintf(f2,'std(x)  =  %15.7f\n',xstd);
fprintf(f2,'rms(x)  =  %15.7f\n',xrms);
fprintf(f2,'running mean(x) =  %15.7f\n',am);
fprintf(f2,'running std(x)  =  %15.7f\n',astd);
fprintf(f2,'running rms(x)  =  %15.7f\n\n\n',arms);

fprintf(f2,'   *****  Results for the first two columns of the input data\n');
fprintf(f2,'          by using the macro  rssxy \n\n');
for k = 1:nrow
   fprintf(f2,'%16.7f  \n',xrssxy(k));
end

fprintf(f2,'\n   *****  Results for the first three columns of the input data\n');
fprintf(f2,'          by using the macro  rss \n\n');
for k = 1:nrow
   fprintf(f2,'%16.7f  \n',xrss(k));
end

disp('  ');
disp('End of the program  XSTAT');
disp('  ');