/usr/share/octave/packages/control-3.0.0/sumblk.m is in octave-control 3.0.0-2.
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 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 | ## Copyright (C) 2009-2015 Lukas F. Reichlin
##
## This file is part of LTI Syncope.
##
## LTI Syncope 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.
##
## LTI Syncope 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 LTI Syncope. If not, see <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn{Function File} {@var{S} =} sumblk (@var{formula})
## @deftypefnx{Function File} {@var{S} =} sumblk (@var{formula}, @var{n})
## Create summing junction @var{S} from string @var{formula}
## for name-based interconnections.
##
## @strong{Inputs}
## @table @var
## @item formula
## String containing the formula of the summing junction,
## e.g. @code{e = r - y + d}
## @item n
## Signal size. Default value is 1.
## @end table
##
## @strong{Outputs}
## @table @var
## @item S
## State-space model of the summing junction.
## @end table
##
## @strong{Example}
## @example
## @group
## octave:1> S = sumblk ('e = r - y + d')
##
## S.d =
## r y d
## e 1 -1 1
##
## Static gain.
## octave:2> S = sumblk ('e = r - y + d', 2)
##
## S.d =
## r1 r2 y1 y2 d1 d2
## e1 1 0 -1 0 1 0
## e2 0 1 0 -1 0 1
##
## Static gain.
## @end group
## @end example
## @seealso{connect}
## @end deftypefn
## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
## Created: October 2013
## Version: 0.2
function s = sumblk (formula, n = 1)
if (nargin == 0 || nargin > 2)
print_usage ();
endif
if (! ischar (formula))
error ("sumblk: require string as first argument");
endif
if (! is_real_scalar (n) || n < 1)
error ("sumblk: require integer as second argument");
endif
if (length (strfind (formula, "=")) != 1)
error ("sumblk: formula requires exactly one '='");
endif
## if the first signal has no sign, add a plus
if (isempty (regexp (formula, "=\\s*[+-]", "once")))
formula = regexprep (formula, "=", "=+", "once");
endif
## extract operators, remove "=" from formula
operator = regexp (formula, "[=+-]", "match");
if (! strcmp (operator{1}, "="))
error ("sumblk: formula has misplaced '='");
endif
operator = operator(2:end);
formula = formula(formula != "=");
## extract signal names
signal = regexp (formula, "\\s*[+-]\\s*", "split");
if (any (cellfun (@isempty, signal)))
error ("sumblk: formula is missing some input/output names");
endif
outname = signal(1);
inname = signal(2:end);
signs = ones (1, numel (inname));
signs(strcmp (operator, "-")) = -1;
d = kron (signs, eye (n));
s = ss (d);
## NOTE: the dark side returns a tf, but i prefer an ss model
## because in general, transfer functions and mimo
## interconnections don't mix well
if (n > 1)
outgroup = struct (outname{1}, 1:n);
outname = strseq (outname{1}, 1:n);
idx = 1 : n*numel (inname);
idx = reshape (idx, n, []);
idx = num2cell (idx, 1);
ingroup = cell2struct (idx, inname, 2);
tmp = cellfun (@strseq, inname, {1:n}, "uniformoutput", false);
inname = vertcat (tmp{:});
s = set (s, "outgroup", outgroup, "ingroup", ingroup);
endif
s = set (s, "inname", inname, "outname", outname);
endfunction
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