--- /dev/null
+## Copyright (C) 2010, 2011, 2012 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 -*-
+## Display routine for FRD objects.
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: February 2010
+## Version: 0.2
+
+function display (sys)
+
+ sysname = inputname (1);
+ [inname, outname, tsam] = __lti_data__ (sys.lti);
+
+ [inname, m] = __labels__ (inname, "u");
+ [outname, p] = __labels__ (outname, "y");
+
+ w = __freq2str__ (sys.w);
+
+ disp ("");
+
+ for k = 1 : m
+ disp (["Frequency response '", sysname, "' from input '", inname{k}, "' to output ..."]);
+ disp ("");
+ __disp_resp__ (sys.H(:,k,:), w, outname);
+ endfor
+
+ display (sys.lti); # display sampling time
+
+ if (tsam == -2)
+ disp ("Static gain.");
+ elseif (tsam == 0)
+ disp ("Continuous-time frequency response.");
+ else
+ disp ("Discrete-time frequency response.");
+ endif
+
+endfunction
+
+
+function __disp_resp__ (H, w, outname)
+
+ p = rows (H); # number of outputs
+ len = size (H, 3); # number of frequencies
+
+ H = mat2cell (H, ones (1, p), 1, len)(:);
+ H = cellfun (@__resp2str__, H, outname, "uniformoutput", false);
+
+ tsize = terminal_size ();
+ col_freq = columns (w);
+ col_resp = cellfun (@columns, H);
+ col_max = tsize(2) - col_freq;
+ width = cumsum (col_resp);
+
+ start = 0;
+ stop = col_max;
+ while (start < width(end))
+ idx = find (width > start & width <= stop);
+ disp ([w, H{idx}]);
+ disp ("");
+ start = width(idx(end));
+ stop = start + col_max;
+ endwhile
+
+ ## FIXME: Handle case where tsize(2) is not enough
+ ## to display frequencies and one output.
+
+endfunction
+
+
+function str = __freq2str__ (w, title = "w [rad/s]")
+
+ len = rows (w);
+ str = __vec2str__ (w);
+ line = repmat ("-", 1, max (columns (str), columns (title)));
+ str = strvcat (title, line, str);
+ space = repmat (" ", len+2, 1);
+ str = [space, str];
+
+endfunction
+
+
+function str = __resp2str__ (H, outname)
+
+ H = H(:);
+ len = length (H);
+ real_str = __vec2str__ (real (H));
+ im = imag (H);
+ if (any (im))
+ imag_str = __vec2str__ (abs (im), "i");
+ sign_str = repmat (" + ", len, 1);
+ neg = im < 0;
+ sign_str(neg, 2) = "-";
+ str = [real_str, sign_str, imag_str];
+ else
+ str = real_str;
+ endif
+ line = repmat ("-", 1, max (columns (str), columns (outname)));
+ str = strvcat (outname, line, str);
+ space = repmat (" ", len+2, 1);
+ str = [space, str];
+
+endfunction
+
+
+function str = __vec2str__ (vec, post)
+
+ vec = vec(:);
+ tmp = isfinite (vec);
+ tmp = abs (vec(tmp & vec != 0));
+ if (isempty (tmp) || min (tmp) < 1e-3 || max (tmp) > 1e4)
+ str = arrayfun (@(x) sprintf ("%.3e", x), vec, "uniformoutput", false);
+ elseif (all (floor (tmp) == tmp))
+ str = arrayfun (@(x) sprintf ("%d", x), vec, "uniformoutput", false);
+ else
+ str = arrayfun (@(x) sprintf ("%.4f", x), vec, "uniformoutput", false);
+ endif
+ str = strjust (char (str), "right");
+ if (nargin > 1)
+ str = [str, repmat(post, length (vec), 1)];
+ endif
+
+endfunction