/usr/share/octave/packages/signal-1.3.0/schtrig.m is in octave-signal 1.3.0-1.
This file is owned by root:root, with mode 0o644.
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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 | ## Copyright (c) 2012 Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
##
## 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/>.
## -*- texinfo -*-
## @deftypefn {Function File} {[@var{rmsx},@var{w}] =} schtrig (@var{x},@var{lvl},@var{rst}=1)
## Implements a multisignal Schmitt trigger with levels @var{lvl}.
##
## The triger works along the first dimension of the array @var{x}. When @code{@var{rst}==1}
## the state of the trigger for all signals is set to the low state (i.e. 0).
##
## Run @code{demo schtrig} to see an example.
##
## @seealso{clustersegment}
## @end deftypefn
function v = schtrig (x, lvl, rst = 1)
persistent st0;
if length(lvl) == 1
lvl = abs (lvl)*[1 -1];
else
lvl = sort(lvl,'descend');
endif
[nT nc] = size(x);
v = NA (nT, nc);
if rst || isempty(st0)
st0 = zeros(1,nc);
endif
v(1,:) = st0;
## Signal is above up level
up = x > lvl(1);
v(up) = 1;
## Signal is below down level
dw = x < lvl(2);
v(dw) = 0;
## Resolve intermediate states
## Find data between the levels
idx = isnan (v);
ranges = clustersegment (idx');
for i=1:nc
## Record the state at the begining of the interval between levels
if !isempty (ranges{i})
prev = ranges{i}(1,:)-1;
prev(prev<1) = 1;
st0 = v(prev,i);
## Copy the initial state to the interval
ini_idx = ranges{i}(1,:);
end_idx = ranges{i}(2,:);
for j =1:length(ini_idx)
v(ini_idx(j):end_idx(j),i) = st0(j);
endfor
endif
endfor
st0 = v(end,:);
endfunction
%!demo
%! t = linspace(0,1,100)';
%! x = sin (2*pi*2*t) + sin (2*pi*5*t).*[0.8 0.3];
%!
%! lvl = [0.8 0.25]';
%! v = schtrig (x,lvl);
%!
%! h = plot(t,x,t,v);
%! set (h([1 3]),'color','b');
%! set (h([2 4]),'color',[0 1 0.5]);
%! set (h,'linewidth',2);
%! line([0; 1],lvl([1; 1]),'color','r');
%! line([0;1],lvl([2;2]),'color','b')
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