Mercurial > hg > octave-lyh
annotate scripts/plot/fplot.m @ 8874:bd1b1fe9c6e9 ss-3-1-53
bump version info for snapshot
| author | John W. Eaton <jwe@octave.org> |
|---|---|
| date | Wed, 25 Feb 2009 18:35:47 -0500 |
| parents | 4629e3925e75 |
| children | eb63fbe60fab |
| rev | line source |
|---|---|
| 7017 | 1 ## Copyright (C) 2005, 2006, 2007 Paul Kienzle |
| 5820 | 2 ## |
| 3 ## This file is part of Octave. | |
| 4 ## | |
| 5 ## Octave is free software; you can redistribute it and/or modify it | |
| 6 ## under the terms of the GNU General Public License as published by | |
| 7016 | 7 ## the Free Software Foundation; either version 3 of the License, or (at |
| 8 ## your option) any later version. | |
| 5820 | 9 ## |
| 10 ## Octave is distributed in the hope that it will be useful, but | |
| 11 ## WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 ## General Public License for more details. | |
| 14 ## | |
| 15 ## You should have received a copy of the GNU General Public License | |
| 7016 | 16 ## along with Octave; see the file COPYING. If not, see |
| 17 ## <http://www.gnu.org/licenses/>. | |
| 5820 | 18 |
| 19 ## -*- texinfo -*- | |
| 20 ## @deftypefn {Function File} {} fplot (@var{fn}, @var{limits}) | |
| 6781 | 21 ## @deftypefnx {Function File} {} fplot (@var{fn}, @var{limits}, @var{tol}) |
| 5820 | 22 ## @deftypefnx {Function File} {} fplot (@var{fn}, @var{limits}, @var{n}) |
| 6895 | 23 ## @deftypefnx {Function File} {} fplot (@dots{}, @var{fmt}) |
| 6699 | 24 ## Plot a function @var{fn}, within the defined limits. @var{fn} |
| 5820 | 25 ## an be either a string, a function handle or an inline function. |
| 26 ## The limits of the plot are given by @var{limits} of the form | |
| 27 ## @code{[@var{xlo}, @var{xhi}]} or @code{[@var{xlo}, @var{xhi}, | |
| 6781 | 28 ## @var{ylo}, @var{yhi}]}. @var{tol} is the default tolerance to use for the |
| 29 ## plot, and if @var{tol} is an integer it is assumed that it defines the | |
| 6895 | 30 ## number points to use in the plot. The @var{fmt} argument is passed |
| 31 ## to the plot command. | |
| 5820 | 32 ## |
| 33 ## @example | |
| 6699 | 34 ## fplot ("cos", [0, 2*pi]) |
| 35 ## fplot ("[cos(x), sin(x)]", [0, 2*pi]) | |
| 5820 | 36 ## @end example |
| 6781 | 37 ## @seealso{plot} |
| 5820 | 38 ## @end deftypefn |
| 39 | |
| 7017 | 40 ## Author: Paul Kienzle <pkienzle@users.sf.net> |
| 41 | |
| 6781 | 42 function fplot (fn, limits, n, linespec) |
| 8847 | 43 if (nargin < 2 || nargin > 4) |
| 6046 | 44 print_usage (); |
| 5820 | 45 endif |
| 46 | |
| 47 if (nargin < 3) | |
| 6781 | 48 n = 0.002; |
| 5820 | 49 endif |
| 50 | |
| 6781 | 51 have_linespec = true; |
| 52 if (nargin < 4) | |
| 53 have_linespec = false; | |
| 54 endif | |
| 5820 | 55 |
| 6781 | 56 if (ischar (n)) |
| 57 have_linespec = true; | |
| 58 linespec = n; | |
| 59 n = 0.002; | |
| 60 endif | |
| 61 | |
| 6699 | 62 if (strcmp (typeinfo (fn), "inline function")) |
| 63 fn = vectorize (fn); | |
| 64 nam = formula (fn); | |
| 65 elseif (isa (fn, "function_handle")) | |
| 66 nam = func2str (fn); | |
| 5820 | 67 elseif (all (isalnum (fn))) |
| 6781 | 68 nam = fn; |
| 5820 | 69 else |
| 6781 | 70 fn = vectorize (inline (fn)); |
| 71 nam = formula (fn); | |
| 72 endif | |
| 73 | |
| 74 if (floor(n) != n) | |
| 75 tol = n; | |
| 7280 | 76 x0 = linspace (limits(1), limits(2), 5)'; |
| 6781 | 77 y0 = feval (fn, x0); |
| 78 err0 = Inf; | |
| 7280 | 79 n = 8; |
| 6781 | 80 x = linspace (limits(1), limits(2), n)'; |
| 81 y = feval (fn, x); | |
| 82 | |
| 83 while (n < 2 .^ 20) | |
| 84 y00 = interp1 (x0, y0, x, "linear"); | |
| 85 err = 0.5 * max (abs ((y00 - y) ./ (y00 + y))(:)); | |
| 86 if (err == err0 || 0.5 * max (abs ((y00 - y) ./ (y00 + y))(:)) < tol) | |
| 87 break; | |
| 88 endif | |
| 89 x0 = x; | |
| 90 y0 = y; | |
| 91 err0 = err; | |
| 92 n = 2 * (n - 1) + 1; | |
| 93 x = linspace (limits(1), limits(2), n)'; | |
| 94 y = feval (fn, x); | |
| 95 endwhile | |
| 96 else | |
| 97 x = linspace (limits(1), limits(2), n)'; | |
| 98 y = feval (fn, x); | |
| 5820 | 99 endif |
| 100 | |
| 6781 | 101 if (have_linespec) |
| 102 plot (x, y, linespec); | |
| 103 else | |
| 104 plot (x, y); | |
| 105 endif | |
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106 |
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107 if (length (limits) > 2) |
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108 axis (limits); |
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109 endif |
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110 |
| 8507 | 111 if (isvector (y)) |
| 6781 | 112 legend (nam); |
| 113 else | |
| 8507 | 114 for i = 1:columns (y) |
| 6781 | 115 nams{i} = sprintf ("%s(:,%i)", nam, i); |
| 116 endfor | |
| 117 legend (nams{:}); | |
| 118 endif | |
| 5820 | 119 endfunction |
| 7245 | 120 |
| 121 %!demo | |
| 122 %! fplot ("cos", [0, 2*pi]) | |
| 123 | |
| 124 %!demo | |
| 125 %! fplot ("[cos(x), sin(x)]", [0, 2*pi]) |