[Changeset]: Ezplot

[David Bateman]

As discussed for the list of the 111 most used Matlab functions

http://www.jmatlab.org/benchmark.html

from Nick Higham, (see the thread 
http://www.nabble.com/List-of-most-highly-used-matlab-functions.-to18693110.html) 
I implemented the missing ezplot function based on the other ez* functions.

Regards
David

--
David Bateman                                address@hidden
Motorola Labs - Paris                        +33 1 69 35 48 04 (Ph) 
Parc Les Algorithmes, Commune de St Aubin    +33 6 72 01 06 33 (Mob) 
91193 Gif-Sur-Yvette FRANCE                  +33 1 69 35 77 01 (Fax) 

The information contained in this communication has been classified as: 

[x] General Business Information 
[ ] Motorola Internal Use Only 
[ ] Motorola Confidential Proprietary

# HG changeset patch
# User David Bateman <address@hidden>
# Date 1219229704 -7200
# Node ID d2359741b3805ae14ab89a7f22338c91ceba5134
# Parent  920b816f97647551e27eadc9df52841aeb13c5d3
Add the ezplot function

diff --git a/doc/ChangeLog b/doc/ChangeLog
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -1,3 +1,7 @@ 2008-08-19  David Bateman  <address@hidden
+2008-08-20  David Bateman  <address@hidden>
+
+       * interpreter/plot.txi: Document ezplot.
+       
 2008-08-19  David Bateman  <address@hidden>
 
        * interpreter/numbers.txi: Document intwarning.
diff --git a/doc/interpreter/plot.txi b/doc/interpreter/plot.txi
--- a/doc/interpreter/plot.txi
+++ b/doc/interpreter/plot.txi
@@ -208,7 +208,10 @@ legend displaying the name of the plotte
 @DOCSTRING(fplot)
 
 Other functions that can create two-dimensional plots directly from a
-function include @code{ezcontour}, @code{ezcontourf} and @code{ezpolar}.
+function include @code{ezplot), @code{ezcontour}, @code{ezcontourf} and
address@hidden
+
address@hidden(ezplot)
 
 @DOCSTRING(ezcontour)
 
diff --git a/scripts/ChangeLog b/scripts/ChangeLog
--- a/scripts/ChangeLog
+++ b/scripts/ChangeLog
@@ -1,5 +1,9 @@ 2008-08-20  David Bateman  <address@hidden
 2008-08-20  David Bateman  <address@hidden>
 
+       * plot/ezplot.m : New function.
+       * plot/Makefile.in (SOURCES): Add ezplot.m to the list.
+       * plot/__ezplot__.m: Adapt to allow for use with the ezplot function.
+       
        * plot/__go_draw_axes__.m: Don't set pm3d implicit if the plot
        contains a surface. Fixes things like meshc(peaks()).
 
diff --git a/scripts/plot/Makefile.in b/scripts/plot/Makefile.in
--- a/scripts/plot/Makefile.in
+++ b/scripts/plot/Makefile.in
@@ -96,6 +96,7 @@ SOURCES = \
   ezcontour.m \
   ezmeshc.m \
   ezmesh.m \
+  ezplot.m \
   ezplot3.m \
   ezpolar.m \
   ezsurfc.m \
diff --git a/scripts/plot/__ezplot__.m b/scripts/plot/__ezplot__.m
--- a/scripts/plot/__ezplot__.m
+++ b/scripts/plot/__ezplot__.m
@@ -26,15 +26,23 @@ function [h, needusage] = __ezplot__ (pf
   else
     iscontour = false;
   endif
-  if (strcmp (pfunc, "plot3"))
+  if (strcmp (pfunc, "plot"))
+    isplot = true;
+    isplot3 = false;
+    ispolar = false;
+    nargs = 1;
+  elseif (strcmp (pfunc, "plot3"))
+    isplot = false;
     isplot3 = true;
     ispolar = false;
-    nargs = 1
+    nargs = 1;
   elseif (strcmp (pfunc, "polar"))
+    isplot = false;
     isplot3 = false;
     ispolar = true;
     nargs = 1;
   else
+    isplot = false;
     isplot3 = false;
     ispolar = false;
     nargs = 2;
@@ -51,12 +59,25 @@ function [h, needusage] = __ezplot__ (pf
   parametric = false;
   fun = varargin {1};
   if (ischar (fun))
-    fun = vectorize (inline (fun));
-    if (length (argnames (fun)) != nargs)
+    if (exist (fun, "file") || exist (fun, "builtin"))
+      fun = vectorize (inline (cstrcat (fun, "(t)")));
+    else
+      fun = vectorize (inline (fun));
+    endif
+    if (isplot && length (argnames (fun)) == 2)
+      nargs = 2;
+    elseif (length (argnames (fun)) != nargs)
       error ("%s: excepting a function of %d arguments", func, nargs);
     endif
     fstr = formula (fun);
-    if (isplot3)
+    if (isplot)
+      xarg = argnames(fun){1};
+      if (nargs == 2)
+       yarg = argnames(fun){2};
+      else
+       yarg = "";
+      endif
+    elseif (isplot3)
       xarg = "x";
       yarg = "y";
     elseif (ispolar)
@@ -67,36 +88,58 @@ function [h, needusage] = __ezplot__ (pf
       yarg = argnames(fun){2};
     endif
   elseif (strcmp (typeinfo (fun), "inline function"))
-    if (length (argnames (fun)) != nargs)
+    if (isplot && length (argnames (fun)) == 2)
+      nargs = 2;
+    elseif (length (argnames (fun)) != nargs)
       error ("%s: excepting a function of %d arguments", func, nargs);
     endif
     fun = vectorize (fun);
     fstr = formula (fun);
-    if (isplot3)
+    if (isplot)
+      xarg = argnames(fun){1};
+      if (nargs == 2)
+       yarg = argnames(fun){2};
+      else
+       yarg = "";
+      endif
+    elseif (isplot3)
+      xarg = "x";
+      yarg = "y";
+    elseif (isplot || ispolar)
+      xarg = "";
+      yarg = "";
+    else
+      xarg = argnames(fun)(1);
+      yarg = argnames(fun)(2);
+    endif
+  elseif (isa (fun, "function_handle"))
+    fstr = func2str (fun);
+    if (length (findstr (fstr, ")")) != 0)
+      args = regexp (substr (fstr, 3, findstr (fstr, ")")(1) - 3), 
+                    '(\w[\w\d]*)', 'tokens');
+    fstr = substr (fstr, findstr (fstr, ")")(1) + 1);
+    else
+      args = {{"x"}};
+    endif
+    if (isplot && length (args) == 2)
+      nargs = 2;
+    elseif (length (args) != nargs)
+      error ("%s: excepting a function of %d arguments", func, nargs);
+    endif
+    if (isplot)
+      xarg = args{1}{1};
+      if (nargs == 2)
+       yarg = args{2}{1};
+      else
+       yarg = "";
+      endif
+    elseif (isplot3)
       xarg = "x";
       yarg = "y";
     elseif (ispolar)
       xarg = "";
       yarg = "";
     else
-      xarg = argnames(fun)(1);
-      yarg = argnames(fun)(2);
-    endif
-  elseif (isa (fun, "function_handle"))
-    fstr = func2str (fun);
-    args = regexp (substr (fstr, 3, findstr (fstr, ")")(1) - 3), 
-                  '(\w[\w\d]*)', 'tokens');
-    if (length (args) != nargs)
-      error ("%s: excepting a function of %d arguments", func, nargs);
-    endif
-    fstr = substr (fstr, findstr (fstr, ")")(1) + 1);
-    if (isplot3)
-      xarg = "x";
-      yarg = "y";
-    elseif (ispolar)
-      xarg = "";
-      yarg = "";
-    else
       xarg = args{1}{1};
       yarg = args{2}{1};
     endif
@@ -104,13 +147,17 @@ function [h, needusage] = __ezplot__ (pf
     error ("%s: expecting string, inline function or function handle", func);
   endif
 
-  if (nargin > 2)
+  if (nargin > 2 || (nargin == 2 && isplot))
     funx = fun;
     fstrx = fstr;
     funy = varargin {2};
     if (ischar (funy) && ! strcmp (funy, "circ") && ! strcmp (funy, "animate"))
       parametric = true;
-      funy = vectorize (inline (funy));
+      if (exist (funy, "file") || exist (funy, "builtin"))
+       funy = vectorize (inline (cstrcat (funy, "(t)")));
+      else
+       funy = vectorize (inline (funy));
+      endif
       if (length (argnames (funy)) != nargs)
        error ("%s: excepting a function of %d arguments", func, nargs);
       endif
@@ -125,19 +172,35 @@ function [h, needusage] = __ezplot__ (pf
     elseif (isa (funy, "function_handle"))
       parametric = true;
       fstry = func2str (funy);
-      args = regexp (substr (fstry, 3, findstr (fstry, ")")(1) - 3), 
-                    '(\w[\w\d]*)', 'tokens');
+      if (length (findstr (fstry, ")")) != 0)
+       args = regexp (substr (fstry, 3, findstr (fstry, ")")(1) - 3), 
+                      '(\w[\w\d]*)', 'tokens');
+       fstry = substr (fstry, findstr (fstry, ")")(1) + 1);
+      else
+       args = {{"y"}};
+      endif
       if (length (args) != nargs)
        error ("%s: excepting a function of %d arguments", func, nargs);
       endif
-      fstry = substr (fstry, findstr (fstry, ")")(1) + 1);
-    endif
-
-    if (parametric)
+    endif
+
+    if (parametric && isplot)
+      xarg = "x";
+      yarg = "y";
+      if (nargs == 2)
+       error ("%s: can not define a parametric function in this manner");
+      endif
+    endif
+
+    if (!isplot && parametric)
       funz = varargin {3};
       if (ischar (funz) && ! strcmp (funz, "circ") && 
-         ! strcmp (funy, "animate"))
-       funz = vectorize (inline (funz));
+         ! strcmp (funz, "animate"))
+       if (exist (funz, "file") || exist (funz, "builtin"))
+         funz = vectorize (inline (cstrcat (funz, "(t)")));
+       else
+         funz = vectorize (inline (funz));
+       endif
        if (length (argnames (funz)) != nargs)
          error ("%s: excepting a function of %d arguments", func, nargs);
        endif
@@ -162,12 +225,20 @@ function [h, needusage] = __ezplot__ (pf
     endif
   endif
 
-  n = 60;
+  if (isplot && nargs != 2)
+    n = 500; 
+  else
+    n = 60;
+  endif
   domain = [];
   circ = false;
   animate = false;
   if (parametric)
-    iarg = 4;
+    if (isplot)
+      iarg = 3;
+    else
+      iarg = 4;
+    endif
   else
     iarg = 2;
   endif
@@ -197,7 +268,7 @@ function [h, needusage] = __ezplot__ (pf
   endif
 
   if (circ)
-    if (iscontour || isplot3)
+    if (iscontour || isplot3 || isplot)
       needusage = true;
       return;
     endif
@@ -221,15 +292,23 @@ function [h, needusage] = __ezplot__ (pf
     error ("%s: animated graphs not implemented", func);
   endif
 
-  if (isplot3 || ispolar)
+  if (isplot3 || ispolar || (isplot && nargs == 1))
     X = linspace (domain (1), domain (2), n);
+  elseif (isplot && numel (domain) == 2)
+    x = linspace (domain (1), domain (2), n);
+    [X, Y] = meshgrid (x, x);
   else
     x = linspace (domain (1), domain (2), n);
     y = linspace (domain (3), domain (4), n);
     [X, Y] = meshgrid (x, y);
   endif
+
   if (parametric)
-    if (isplot3)
+    if (isplot)
+      XX = feval (funx, X);
+      Z = feval (funy, X);
+      X = XX;
+    elseif (isplot3)
       Z = feval (funz, X);
       XX = feval (funx, X);
       YY = feval (funy, X);
@@ -252,26 +331,77 @@ function [h, needusage] = __ezplot__ (pf
                      '\./', '/'), '[\.]*\*', '');
     fstry = regexprep (regexprep (regexprep (fstry,'\.\^\s*','^'), 
                      '\./', '/'), '[\.]*\*', '');
-    fstrz = regexprep (regexprep (regexprep (fstrz,'\.\^\s*','^'), 
-                     '\./', '/'), '[\.]*\*', '');
-    fstr = cstrcat ("[",fstrx,",",fstry,",",fstrz,"]");
+    if (isplot)
+      fstr = cstrcat ("x = ",fstrx,", y = ",fstry);
+    else
+      fstrz = regexprep (regexprep (regexprep (fstrz,'\.\^\s*','^'), 
+                                   '\./', '/'), '[\.]*\*', '');
+      fstr = cstrcat ("x = ",fstrx,",y = ",fstry,", z = ",fstrz);
+    endif
   else
     if (isplot3)
       needusage = true;
       return;
     endif
 
-    if (ispolar)
-      Z = feval (fun, X);
-    else
-      Z = feval (fun, X, Y);
-
-      ## Eliminate the singularities
-      Z = __eliminate_sing__ (Z);
-    endif
-
     fstr = regexprep (regexprep (regexprep (fstr,'\.\^\s*','^'), '\./', '/'), 
                      '[\.]*\*', '');
+    if (isplot && nargs == 2)
+      if (strcmp (typeinfo (fun), "inline function") && 
+         !isempty (strfind (formula (fun) , "=")))
+       fun = inline (cstrcat (strrep (formula (fun), "=", "- ("), ")"));
+      else
+       fstr = cstrcat (fstr, " = 0");
+      endif
+
+      Z = feval (fun, X, Y);
+
+      ## Matlab returns line objects for this case and so can't call 
+      ## contour directly as it returns patch objects to allow colormaps
+      ## to work with contours. Therefore recreate the lines from the
+      ## output for contourc, and store in cell arrays.
+      [c, lev] = contourc (X, Y, Z, [0, 0]);
+
+      i1 = 1;
+      XX = {};
+      YY = {};
+      while (i1 < length (c))
+       clev = c(1,i1);
+       clen = c(2,i1);
+       XX = [XX, {c(1, i1+1:i1+clen)}];
+       YY = [YY, {c(2, i1+1:i1+clen)}];
+       i1 += clen+1;
+      endwhile
+    else  
+      if (ispolar)
+       Z = feval (fun, X);
+      elseif (isplot)
+       Z = real (feval (fun, X));
+
+       ## Eliminate the singularities. This seems to be what matlab
+       ## does, but can't be sure.
+       XX = sort (Z (isfinite (Z)));
+       if (length (X) > 4)
+         d = XX(fix (7 * length (XX) / 8)) - XX(fix (length (XX) / 8));
+         yrange = [max(XX(1) - d/8, XX(fix (length (XX) / 8)) - d), ...
+                   min(XX(end) + d/8, XX(fix (7 * length (XX) / 8)) + d)];
+       else
+         yrange = [XX(1), XX(end)];
+        endif
+
+       idx = 2 : length(Z);
+       idx = find (((Z(idx) > yrange(2) / 2) & (Z(idx-1) < yrange(1) / 2)) |
+                ((Z(idx) < yrange(1) / 2) & (Z(idx-1) > yrange (2) / 2)));
+       if (any(idx))
+         Z(idx) = NaN; 
+       endif
+      else
+       Z = feval (fun, X, Y);
+
+       ## Eliminate the singularities
+       Z = __eliminate_sing__ (Z);
+      endif
+    endif
   endif
 
   oldax = gca (); 
@@ -279,8 +409,21 @@ function [h, needusage] = __ezplot__ (pf
     axes (ax);
     if (iscontour)
       [clev, h] = feval (pfunc, X, Y, Z);
-    elseif (ispolar)
+    elseif (isplot && nargs == 2)
+      h = [];
+      hold_state = get (ax, "nextplot");
+      for i = 1 : length (XX)
+       h = [h; plot(XX{i}, YY{i})];
+       if (i == 1)
+         set (ax, "nextplot", "add")
+       endif
+      endfor
+      set (ax, "nextplot", hold_state)
+    elseif (ispolar || isplot)
       h = feval (pfunc, X, Z);
+      if (isplot && !parametric)
+       axis ([X(1), X(end), yrange]);
+      endif
     else
       h = feval (pfunc, X, Y, Z);
     endif
diff --git a/scripts/plot/ezplot.m b/scripts/plot/ezplot.m
new file mode 100644
--- /dev/null
+++ b/scripts/plot/ezplot.m
@@ -0,0 +1,89 @@
+## Copyright (C) 2008 David Bateman
+##
+## 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 3 of the License, 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, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} ezplot (@var{f})
+## @deftypefnx {Function File} {} ezplot (@var{fx}, @var{fy})
+## @deftypefnx {Function File} {} ezplot (@dots{}, @var{dom})
+## @deftypefnx {Function File} {} ezplot (@dots{}, @var{n})
+## @deftypefnx {Function File} {} ezplot (@var{h}, @dots{})
+## @deftypefnx {Function File} address@hidden =} ezplot (@dots{})
+##
+## Plots in two-dimensions the curve defined by @var{f}. The function
+## @var{f} may be a string, inline function or function handle and can
+## have either one or two variables. If @var{f} has one variable, then 
+## the function is plotted over the domain @code{-2*pi < @var{x} < 2*pi}  
+## with 500 points. 
+##
+## If @var{f} has two variables then @address@hidden(@var{x},@var{y}) = 0}
+## is calculated over the meshed domain @code{-2*pi < @var{x} | @var{y}
+## < 2*pi} with 60 by 60 in the mesh. For example
+##
+## @example
+## ezplot (@@(@var{x}, @var{y}) @var{x} .^ 2 - @var{y} .^ 2 - 1)
+## @end example
+##
+## If two functions are passed as strings, inline functions or function
+## handles, then the parametric function
+##
+## @example
+## @group
+## @var{x} = @var{fx} (@var{t})
+## @var{y} = @var{fy} (@var{t})
+## @end group
+## @end example
+##
+## is plotted over the domain @code{-2*pi < @var{t} < 2*pi} with 500
+## points. 
+##
+## If @var{dom} is a two element vector, it represents the minimum and maximum
+## value of @var{x}, @var{y} and @var{t}. If it is a four element
+## vector, then the minimum and maximum values of @var{x} and @var{t}
+## are determined by the first two elements and the minimum and maximum
+## of @var{y} by the second pair of elements.
+##
+## @var{n} is a scalar defining the number of points to use in plotting
+## the function.
+##
+## The optional return value @var{h} provides a list of handles to the 
+## the line objects plotted.
+##
+## @seealso{plot, ezplot3}
+## @end deftypefn
+
+function retval = ezplot (varargin)
+
+  [h, needusage] = __ezplot__ ("plot", varargin{:});
+
+  if (needusage)
+    print_usage ();
+  endif
+
+  if (nargout > 0)
+    retval = h;
+  endif
+endfunction
+
+%!demo
+%! ezplot (@cos, @sin)
+
+%!demo
+%! ezplot ("1/x")
+
+%!demo
+%! ezplot (inline("x^2 - y^2 = 1"))