Merge pull request #1279 from gnu-octave/add_fplot

New function, fplot

NEWS

@@ -1,6 +1,10 @@
 octsympy 3.1.1+
 ===============
 
+  * New symbolic commands:
+
+          fplot
+
   * Move repo to https://github.com/gnu-octave/symbolic
   * `sym(<array>, ratflag)` now respects `ratflag` (issue #1273).
   * Changed metainfo.xml ID and corrected long-standing "Addon"

inst/@sym/ezmesh.m

@@ -1,4 +1,4 @@
-%% Copyright (C) 2019 Colin B. Macdonald
+%% Copyright (C) 2019, 2023 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -81,12 +81,10 @@
         assert(length(thissym) <= 2, ...
           'ezmesh: parameterized: functions should have at most two inputs');
         if (isempty(thissym))
-          % a number, create a constant function in a dummy variable
-          % (0*t works around some Octave oddity on 3.8 and hg Dec 2014)
-          thisf = inline(sprintf('%g + 0*t', double(varargin{i})), 't');
-          %thisf = @(t) 0*t + double(varargin{i});  % no
+          % constant function
+          thisf = function_handle (varargin{i}, 'vars', sym ('t'));
         else
-          % check variables match (sanity check)
+          % check variables match over each function
           if (isempty(firstsym))
             firstsym = thissym;
           else

inst/@sym/ezplot.m

@@ -1,4 +1,4 @@
-%% Copyright (C) 2014-2017 Colin B. Macdonald
+%% Copyright (C) 2014-2017, 2023 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -73,7 +73,7 @@
 %% The solution, as shown in the example, is to convert the sym to
 %% a double.
 %%
-%% @seealso{ezplot, @@sym/ezplot3, @@sym/ezsurf, @@sym/function_handle}
+%% @seealso{ezplot, @@sym/ezplot3, @@sym/ezsurf, @@sym/fplot, @@sym/function_handle}
 %% @end defmethod
 
 
@@ -102,12 +102,10 @@
         assert(length(thissym) <= 2, ...
           'ezplot: plotting curves: functions should have at most two inputs');
         if (isempty(thissym))
-          % a number, create a constant function in a dummy variable
-          % (0*t works around some Octave oddity on 3.8 and hg Dec 2014)
-          thisf = inline(sprintf('%g + 0*t', double(varargin{i})), 't');
-          %thisf = @(t) 0*t + double(varargin{i});  % no
+          % constant function
+          thisf = function_handle (varargin{i}, 'vars', sym ('t'));
         else
-          % check variables match (sanity check)
+          % check variables match over each function
           if (isempty(firstsym))
             firstsym = thissym;
           else

inst/@sym/ezplot3.m

@@ -1,4 +1,4 @@
-%% Copyright (C) 2014-2016 Colin B. Macdonald
+%% Copyright (C) 2014-2016, 2023 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -66,12 +66,10 @@
         assert(length(thissym) <= 1, ...
           'ezplot3: plotting curves: functions should have at most one input');
         if (isempty(thissym))
-          % a number, create a constant function in a dummy variable
-          % (0*t works around some Octave oddity on 3.8 and hg Dec 2014)
-          thisf = inline(sprintf('%g + 0*t', double(varargin{i})), 't');
-          %thisf = @(t) 0*t + double(varargin{i});  % no
+          % constant function
+          thisf = function_handle (varargin{i}, 'vars', sym ('t'));
         else
-          % check variables match (sanity check)
+          % check variables match over each function
           if (isempty(firstsym))
             firstsym = thissym;
           else

inst/@sym/ezsurf.m

@@ -1,4 +1,4 @@
-%% Copyright (C) 2016-2017, 2019 Colin B. Macdonald
+%% Copyright (C) 2016-2017, 2019, 2023 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -80,13 +80,11 @@
         thissym = symvar(varargin{i});
         assert(length(thissym) <= 2, ...
           'ezsurf: parameterized: functions should have at most two inputs');
-        if (isempty(thissym))
-          % a number, create a constant function in a dummy variable
-          % (0*t works around some Octave oddity on 3.8 and hg Dec 2014)
-          thisf = inline(sprintf('%g + 0*t', double(varargin{i})), 't');
-          %thisf = @(t) 0*t + double(varargin{i});  % no
+        if (isempty (thissym))
+          % constant function
+          thisf = function_handle (varargin{i}, 'vars', sym ('t'));
         else
-          % check variables match (sanity check)
+          % check variables match over each function
           if (isempty(firstsym))
             firstsym = thissym;
           else

inst/@sym/fplot.m

@@ -0,0 +1,211 @@
+%% Copyright (C) 2023 Colin B. Macdonald
+%%
+%% This file is part of OctSymPy.
+%%
+%% OctSymPy 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 software 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 software; see the file COPYING.
+%% If not, see <http://www.gnu.org/licenses/>.
+
+%% -*- texinfo -*-
+%% @documentencoding UTF-8
+%% @defmethod  @@sym fplot (@var{f})
+%% @defmethodx @@sym fplot (@var{f}, @var{limits})
+%% @defmethodx @@sym fplot (@dots{}, @dots{}, @var{N})
+%% @defmethodx @@sym fplot (@dots{}, @dots{}, @var{tol})
+%% @defmethodx @@sym fplot (@dots{}, @dots{}, @var{fmt})
+%% @defmethodx @@sym {[@var{x}, @var{y}] =} fplot (@dots{})
+%% Plot a symbolic expression.
+%%
+%% Examples:
+%% @example
+%% @group
+%% syms x
+%% y = cos(3*x)
+%%   @result{} y = (sym) cos(3⋅x)
+%%
+%% @c doctest: +SKIP
+%% fplot (y)
+%%
+%% @c doctest: +SKIP
+%% fplot (y, [0 pi])
+%% @end group
+%% @end example
+%%
+%% You can also grab the data that would be plotted and plot it
+%% yourself:
+%% @example
+%% @group
+%% syms x
+%%
+%% @c doctest: +SKIP_IF(compare_versions (OCTAVE_VERSION(), '6.0.0', '<'))
+%% [xx, yy] = fplot (sin (x), [0 1])
+%%   @result{} xx =
+%%       0
+%%       ...
+%%       1.0000
+%%   @result{} yy =
+%%       0
+%%       ...
+%%       0.8415
+%%
+%% @c doctest: +SKIP
+%% plot (xx, yy)
+%% @end group
+%% @end example
+%%
+%% See help for the (non-symbolic) @code{fplot}, which this
+%% routine calls after trying to convert sym inputs to
+%% anonymous functions.
+%%
+%% @seealso{fplot, @@sym/ezplot, @@sym/function_handle}
+%% @end defmethod
+
+
+function [xx, yy] = fplot (varargin)
+
+  % first input is handle, shift
+  if (ishandle (varargin{1}))
+    fshift = 1;
+  else
+    fshift = 0;
+  end
+
+  for i = (1+fshift):nargin
+    if (isa (varargin{i}, 'sym'))
+      if (i == 1 + fshift)
+        thissym = symvar (varargin{i});
+        assert (length (thissym) <= 1, ...
+          'fplot: functions should have at most one input');
+        if (isempty (thissym))
+          thisf = function_handle (varargin{i}, 'vars', sym ('x'));
+        else
+          thisf = function_handle (varargin{i});
+        end
+
+        varargin{i} = thisf;
+
+      else
+        % plot ranges, etc, convert syms to doubles
+        varargin{i} = double (varargin{i});
+      end
+    end
+  end
+
+  if (nargout)
+    [xx, yy] = fplot (varargin{:});
+  else
+    fplot(varargin{:});
+  end
+
+end
+
+
+%!test
+%! % simple
+%! syms x
+%! f = cos (x);
+%! fplot (f);
+
+%!test
+%! % constant function
+%! fplot (sym (10));
+
+%!test
+%! syms x
+%! f = cos (x);
+%! [xx, yy] = fplot (f);
+%! assert (xx(1), -5)
+%! assert (xx(end), 5)
+%! assert (min (yy), -1, 0.1)
+%! assert (max (yy), 1, 0.1)
+
+%!test
+%! syms x
+%! f = cos (x);
+%! dom = [1 3];
+%! [xx, yy] = fplot (f, dom);
+%! assert (xx(1), dom(1))
+%! assert (xx(end), dom(2))
+
+%!test
+%! syms x
+%! f = cos (x);
+%! dom = [1 3];
+%! fplot (f, dom);
+%! assert (get (gca, 'xlim'), dom)
+
+%!test
+%! syms x
+%! f = exp (x);
+%! dom = [1 2 3 4];
+%! fplot (f, dom);
+%! assert (get (gca, 'xlim'), dom(1:2))
+%! assert (get (gca, 'ylim'), dom(3:4))
+
+%!test
+%! % bounds as syms
+%! syms x
+%! f = cos (x);
+%! dom = [1 2 3 4];
+%! fplot (f, sym (dom));
+%! assert (get (gca, 'xlim'), dom(1:2))
+%! assert (get (gca, 'ylim'), dom(3:4))
+
+%!test
+%! % bounds as syms, regular handle for function
+%! % fails on 6.1.0, maybe earlier too?
+%! if (compare_versions (OCTAVE_VERSION (), '6.1.0', '!='))
+%!   dom = [1 2];
+%!   fplot (@cos, sym (dom));
+%!   assert (get (gca, 'xlim'), dom(1:2))
+%! end
+
+%!error <at most one>
+%! syms x y
+%! fplot (x*y)
+
+%!test
+%! % N parameter does something
+%! syms x
+%! [xx, yy] = fplot (sin (x), [0 2], 5);
+%! N = length (xx);
+%! assert (N >= 5)
+%! [xx, yy] = fplot (sin (x), [0 2], 1000);
+%! N = length (xx);
+%! assert (N == 1000)
+
+%!test
+%! % tolerance parameter does something
+%! syms x
+%! [xx, yy] = fplot (sin (exp (x/2)), [0 3], 0.1);
+%! N1 = length (xx);
+%! [xx, yy] = fplot (sin (exp (x/2)), [0 3], 0.01);
+%! N2 = length (xx);
+%! assert (N2 > N1)
+
+%!test
+%! % fmt parameter does something
+%! syms x
+%! fplot (sin (x), [0 6], 'rx--', 'linewidth', 5);
+%! l = get (gca (), 'children');
+%! assert (get (l, 'color'), [1 0 0])
+%! assert (get (l, 'linewidth'), 5)
+
+%! f = exp (x);
+%! dom = [1 2 3 4];
+%! fplot (f, dom);
+%! assert (get (gca, 'xlim'), dom(1:2))
+%! assert (get (gca, 'ylim'), dom(3:4))
+
+%!test
+%! close all

inst/@sym/function_handle.m

@@ -122,7 +122,7 @@
     M.name = out{1}{1};
     M.code = out{1}{2};
 
-    assert (strcmp (M.name, [fcnname '.m']), 'sanity check failed: names should match');
+    assert (strcmp (M.name, [fcnname '.m']), 'correctness check failed: names should match');
 
     file_to_write = fullfile(fcnpath, [fcnname '.m']);
     [fid,msg] = fopen(file_to_write, 'w');

util/convert_comments.m

@@ -1,4 +1,4 @@
-%% Copyright (C) 2014-2018 Colin B. Macdonald
+%% Copyright (C) 2014-2018, 2023 Colin B. Macdonald
 %%
 %% This file is part of OctSymPy.
 %%
@@ -209,7 +209,7 @@ function convert_comments (basedir, subdir, dirout)
   N = Nfcn;
   fcn_line = ins{N};
 
-  % sanity checks
+  % correctness checks
   I = strfind(ins{N+1}, '%');
   if ~isempty(I) && I(1) == 1
     ins{N}