Mercurial > octave
view scripts/plot/stairs.m @ 245:16a24e76d6e0
[project @ 1993-12-03 02:00:15 by jwe]
author | jwe |
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date | Fri, 03 Dec 1993 02:00:15 +0000 |
parents | 5b46fbec1488 |
children | c8f88bd3202b |
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# Copyright (C) 1993 John W. Eaton # # This file is part of Octave. # # Octave 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, or (at your option) any # later version. # # Octave 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 Octave; see the file COPYING. If not, write to the Free # Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. function [xs, ys] = stairs (x, y) # usage: [xs, ys] = stairs (x, y) # # Given two vectors of x-y data, stairs produces a `stairstep' plot. # # If only one argument is given, it is taken as a vector of y-values # and the x coordiates are taken to be the indices of the elements. # # If two output arguments are specified, the data are generated but # not plotted. For example, # # stairs (x, y); # # and # # [xs, ys] = stairs (x, y); # plot (xs, ys); # # are equivalent. # # See also: plot, semilogx, semilogy, loglog, polar, mesh, contour, # bar, gplot, gsplot, replot, xlabel, ylabel, title if (nargin == 1) if (is_vector (x)) len = 2 * length (x); xs = ys = zeros (len, 1); k = 0; for i = 1:2:len xs(i) = k++; ys(i) = x(k); ys(i+1) = x(k); xs(i+1) = k; endfor else error ("stairs: argument must be a vector"); endif elseif (nargin == 2) if (is_vector (x) && is_vector (y)) xlen = length (x); ylen = length (y); if (xlen == ylen) len = 2 * xlen; xs = ys = zeros (len, 1); k = 1; len_m2 = len - 2; for i = 1:2:len_m2 xs(i) = x(k); ys(i) = y(k); ys(i+1) = y(k); k++; xs(i+1) = x(k); if (x(k) < x(k-1)) error ("stairs: x vector values must be in ascending order"); endif endfor xs(len-1) = x(xlen); delta = x(xlen) - x(xlen-1); xs(len) = x(xlen) + delta; ys(len-1) = y(ylen); ys(len) = y(ylen); else error ("stairs: arguments must be the same length"); endif else error ("stairs: arguments must be vectors"); endif else error ("usage: [xs, ys] = stairs (x, y)"); endif if (nargout == 1) plot (xs, ys); endif endfunction