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slice implementation
From: |
Kai Habel |
Subject: |
slice implementation |
Date: |
Fri, 23 Nov 2007 08:37:56 +0100 |
User-agent: |
Thunderbird 2.0.0.6 (X11/20070801) |
Hello all,
I have implemented the slice function, which is useful to visualize 3D
scalar fields by means of slices. Since we have some pending patches for
__go_draw_axes__, ... (and I have some applied locally) I am not sure if
slice works without warnings or errors using the current cvs. If series
of patches from David is applied, I will look at slice again and see if
some modifications are needed.
I think slice shows a further problem with gnuplot, If you take the
example code and try to plot three orthogonal slices
slice(X,Y,Z,V,0,0,0) instead of slice(X,Y,Z,V,[],0,[]) you see a
distorted plot, because the depth ordering does not work for this case.
Maybe you have an idea?
Kai
## Copyright (C) 2007 Kai Habel, 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} {} slice (@var{X}, @var{Y}, @var{Z}, @var{V},
@var{SX}, @var{SY}, @var{SZ})
## @deftypefnx {Function File} {} slice (@var{X}, @var{Y}, @var{Z}, @var{V},
@var{XI}, @var{YI}, @var{ZI})
## @deftypefnx {Function File} {} slice (@var{V}, @var{SX}, @var{SY}, @var{SZ})
## @deftypefnx {Function File} {} slice (@var{V}, @var{XI}, @var{YI}, @var{ZI})
## @deftypefnx {Function File} address@hidden =} slice (...)
## @deftypefnx {Function File} address@hidden =} slice (...,@var{METHOD})
## Plots slice(s) of 3D data/scalar fields. Each element of then 3-dimensional
## array @var{v} represents a scalar value at a location given by the
parameters
## @var{x}, @var{y}, and @var{z}. The parameters @var{x}, @var{x}, and
## @var{z} are either 3-dimensional arrays of the same size as the array
## @var{v} in the 'meshgrid' format or vectors. The parameters @var{xi}, etc
## respect a similar format to @var{x}, etc, and they represent the points
## at which the array @var{vi} is interpolated using interp3. The vectors
## @var{sx}, @var{sy}, and @var{sz} contain points of orthogonal slices of
## the respective axes.
##
## If @var{x}, @var{y}, @var{z} are omitted, they are assumed to be
## @code{x = 1 : size (@var{v}, 2)}, @code{y = 1 : size (@var{v}, 1)} and
## @code{z = 1 : size (@var{v}, 3)}.
##
## @var{Method} is one of:
##
## @table @asis
## @item 'nearest'
## Return the nearest neighbour.
## @item 'linear'
## Linear interpolation from nearest neighbours.
## @item 'cubic'
## Cubic interpolation from four nearest neighbours (not implemented yet).
## @item 'spline'
## Cubic spline interpolation--smooth first and second derivatives
## throughout the curve.
## @end table
##
## The default method is 'linear'.
## The optional return value @var{H} is a vector of handles to the surface
graphic
## objects.
##
## Examples:
## @example
## [X,Y,Z] = meshgrid(linspace(-8,8,32));
## V = sin (sqrt (X.^2 + Y.^2 + Z.^2)) ./ (sqrt (X.^2 + Y.^2 + Z.^2))
## slice(X,Y,Z,V,[],0,[])
## [XI,YI]=meshgrid(linspace(-7,7));
## ZI=XI+YI;
## slice(X,Y,Z,V,XI,YI,ZI)
## @end example
## @seealso{interp3, surface, pcolor}
## @end deftypefn
## Author: Kai Habel <kai.habel at gmx.de>
function h = slice(varargin)
method = "linear";
extrapval = NA;
nargs = nargin;
if (ischar (varargin{end}))
method = varargin{end};
nargs -= 1;
endif
if (nargs == 4)
V = varargin{1};
if (ndims (V) != 3)
error ("slice: expect 3-dimensional array of values");
endif
[nx, ny, nz] = size(V);
[X,Y,Z] = meshgrid(1:nx,1:ny,1:nz);
sx = varargin{2};
sy = varargin{3};
sz = varargin{4};
elseif (nargs == 7)
V = varargin{4};
if (ndims (V) != 3)
error ("slice: expect 3-dimensional array of values");
endif
X = varargin{1};
Y = varargin{2};
Z = varargin{3};
if (all([isvector(X) isvector(Y) isvector(Z)]))
[X,Y,Z] = meshgrid(X,Y,Z);
elseif ((ndims(X) == 3) && size_equal(X,Y) && size_equal(X,Z))
##do nothing
else
error("slice: X,Y,Z size mismatch")
endif
sx = varargin{5};
sy = varargin{6};
sz = varargin{7};
else
print_usage();
endif
if (any([isvector(sx), isvector(sy), isvector(sz)]))
have_sval = true();
elseif ((ndims(sx) == 2) && size_equal(sx,sy) && size_equal(sx,sz))
have_sval = false();
else
error ("slice: dimensional mismatch for (XI,YI,ZI) or (sx,sy,sz)");
endif
newplot ();
ax = gca;
sidx = 1;
maxv = max(V(:));
minv = min(V(:));
set(ax, "CLim", [minv, maxv]);
if (have_sval)
ns = length(sx) + length(sy) + length(sz);
hs = zeros(ns,1);
[ny, nx, nz] = size(V);
if (length(sz) > 0)
for i=1:length(sz)
[XI,YI,ZI] = meshgrid(squeeze(X(1,:,1)),squeeze(Y(:,1,1)),sz(i));
Vz = squeeze(interp3(X,Y,Z,V,XI,YI,ZI,method));
tmp(sidx++) = surface(XI,YI,sz(i)*ones(size(YI)),Vz);
endfor
endif
if (length(sy) > 0)
for i=length(sy):-1:1
[XI,YI,ZI] = meshgrid(squeeze(X(1,:,1)),sy(i),squeeze(Z(1,1,:)));
Vy = squeeze(interp3(X,Y,Z,V,XI,YI,ZI,method));
tmp(sidx++) =
surface(squeeze(XI),squeeze(sy(i)*ones(size(ZI))),squeeze(ZI),Vy);
endfor
endif
if (length(sx) > 0)
for i=length(sx):-1:1
[XI,YI,ZI] = meshgrid(sx(i),squeeze(Y(:,1,1)),squeeze(Z(1,1,:)));
Vx = squeeze(interp3(X,Y,Z,V,XI,YI,ZI,method));
tmp(sidx++) =
surface(squeeze(sx(i)*ones(size(ZI))),squeeze(YI),squeeze(ZI),Vx);
endfor
endif
else
VI = interp3(X,Y,Z,V,sx,sy,sz);
tmp(sidx++) = surface(sx,sy,sz,VI);
endif
if (! ishold ())
set (ax, "view", [-37.5, 30.0]);
endif
if (nargout > 0)
h = tmp;
endif
end
- slice implementation,
Kai Habel <=