/usr/share/octave/packages/tsa-4.2.7/histo4.m is in octave-tsa 4.2.7-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 | function [R, tix] = histo4(Y, W)
% HISTO4 calculates histogram of multidimensional data samples
% and supports data compression
%
% R = HISTO4(Y)
% R = HISTO4(Y, W)
% Y data: on sample per row, each sample has with size(Y,2) elements
% W weights of each sample (default: [])
% W = [] indicates that each sample has equal weight
% R is a struct with these fields:
% R.X are the bin-values
% R.H is the frequency of occurence of value X (weighted with W)
% R.N are the total number of samples (or sum of W)
%
% HISTO4 might be useful for data compression, because
% [R,tix] = histo4(Y)
% is the compression step
% R.X(tix,:)
% is the decompression step
%
% The effort (in memory and speed) for compression is O(n*log(n))
% The effort (in memory and speed) for decompression is only O(n)
%
% see also: HISTO, HISTO2, HISTO3, HISTO4
%
% REFERENCE(S):
% C.E. Shannon and W. Weaver 'The mathematical theory of communication' University of Illinois Press, Urbana 1949 (reprint 1963).
% $Id: histo4.m 11693 2013-03-04 06:40:14Z schloegl $
% Copyright (C) 1996-2005,2008,2009,2011 by Alois Schloegl <alois.schloegl@gmail.com>
% This is part of the TSA-toolbox
% http://pub.ist.ac.at/~schloegl/matlab/tsa/
%
% 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 3 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/>.
%%%%% check input arguments %%%%%
[yr, yc] = size(Y);
if nargin<2,
W = [];
end;
if ~isempty(W) && (yr ~= numel(W)),
error('number of rows of Y does not match number of elements in W');
end;
%%%%% identify all possible X's and generate overall Histogram %%%%%
[Y, idx] = sortrows(Y);
d = diff(Y,[],1);
ix = any( (~isnan(d) & (d~=0) ) | diff(isnan(Y),[],1), 2);
tmp = [find(ix); yr];
R.X = Y(tmp,:);
R.datatype = 'HISTOGRAM';
if isempty(W)
R.H = [tmp(1); diff(tmp)];
R.N = yr;
else
W = cumsum(W(idx));
R.H = [W(tmp(1)); diff(W(tmp))];
R.N = W(end);
end;
%%%%% generate inverse index %%%%%
if nargout>1,
tix = cumsum([1;ix]); % rank
cc = 1;
tmp = sum(ix);
if tmp < 2^8;
tix = uint8(tix);
cc = 8/1;
elseif tmp < 2^16;
tix = uint16(tix);
cc = 8/2;
elseif tmp < 2^32;
tix = uint32(tix);
cc = 8/4;
end;
[tmp, idx] = sort(idx); % inverse index
tix = tix(idx); % inverse sort rank
R.compressionratio = (prod(size(R.X)) + yr/cc) / (yr*yc);
R.tix = tix;
end;
|