## Copyright (C) 2003 Alberto Terruzzi ## ## This program is free software; you can redistribute it and/or modify ## it under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 2 of the License, or ## (at your option) any later version. ## ## This program is distributed in the hope that it will be useful, ## but WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ## GNU General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with this program; If not, see <http://www.gnu.org/licenses/>. ## usage: table = tabulate (data,edges) ## ## Frequency table. ## ## table = tabulate (data,edges), for vector data, counts the number of ## values in data that fall between the elements in the edges vector ## (which must contain monotonically non-decreasing values). table is a ## matrix. ## The first column of table is the number of bin, the second ## is the number of instances in each class (absolute frequency). The ## third column contains the percentage of each value (relative ## frequency) and the fourth column contains the cumulative frequency. ## If edges is missed the width of each class is unitary, if edges is a ## scalar then represent the number of classes, or you can define the ## width of each bin. ## table(k,2) will count the value data(i) if edges(k) <= data(i) < ## edges(k+1). The last bin will count the value of data(i) if ## edges(k) <= data(i) <= edges(k+1). ## Values outside the values in edges are not counted. Use -inf and inf ## in edges to include all values. ## Tabulate with no output arguments returns a formatted table in the ## command window. ## ## Example ## ## sphere_radius = [1:0.05:2.5]; ## tabulate (sphere_radius) ## ## Tabulate returns 2 bins, the first contains the sphere with radius ## between 1 and 2 mm excluded, and the second one contains the sphere with ## radius between 2 and 3 mm. ## ## tabulate (sphere_radius,10) ## ## Tabulate returns ten bins. ## ## tabulate (sphere_radius,[1 1.5 2 2.5]) ## ## Tabulate returns three bins, the first contains the sphere with radius ## between 1 and 1.5 mm excluded, the second one contains the sphere with ## radius between 1.5 and 2 mm excluded, and the third contains the sphere with ## radius between 2 and 2.5 mm. ## ## bar (table(:,1),table(:,2)) ## ## draw histogram. ## ## See also bar and pareto. ## Author: Alberto Terruzzi <t-albert@libero.it> ## Version: 1.0 ## Created: 13 February 2003 function table = tabulate (varargin) if nargin < 1 || nargin > 2 usage("table = tabulate (data,edges)") endif data = varargin{1}; if isvector (data) != 1 error ("data must be a vector."); endif n = length(data); m = min(data); M = max(data); if nargin == 1 edges = 1:1:max(data)+1; else edges = varargin{2}; end if isscalar(edges) h=(M-m)/edges; edges = [m:h:M]; end # number of classes bins=length(edges)-1; # initialize freqency table freqtable = zeros(bins,4); for k=1:1:bins; if k != bins freqtable(k,2)=length(find (data >= edges(k) & data < edges(k+1))); else freqtable(k,2)=length(find (data >= edges(k) & data <= edges(k+1))); end if k == 1 freqtable (k,4) = freqtable(k,2); else freqtable(k,4) = freqtable(k-1,4) + freqtable(k,2); end end freqtable(:,1) = edges(1:end-1)(:); freqtable(:,3) = 100*freqtable(:,2)/n; if nargout == 0 disp(" bin Fa Fr% Fc"); printf("%8g %5d %6.2f%% %5d\n",freqtable'); else table = freqtable; end endfunction

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