Mercurial > octave-nkf
changeset 18202:5646f999245d
voronoi.m: Add special handling for 2-point input (bug #40996).
* voronoi.m: Check for 2-point input and find single bisection line between
them amongs the edges output from QHull. Add %!test for special case.
Change input validation and %!tests to accept 2-point input.
| author | Rik <rik@octave.org> |
|---|---|
| date | Fri, 03 Jan 2014 10:52:41 -0800 |
| parents | ec87e965c246 |
| children | adbbacce8aaf |
| files | scripts/geometry/voronoi.m |
| diffstat | 1 files changed, 30 insertions(+), 13 deletions(-) [+] |
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--- a/scripts/geometry/voronoi.m Fri Jan 03 12:52:49 2014 -0500 +++ b/scripts/geometry/voronoi.m Fri Jan 03 10:52:41 2014 -0800 @@ -107,10 +107,8 @@ if (length (x) != length (y)) error ("voronoi: X and Y must be vectors of the same length"); - elseif (length (x) < 3) - ## See bug #40996. - ## For 2 points it would be nicer to just calculate the bisection line. - error ("voronoi: minimum of 3 points needed"); + elseif (length (x) < 2) + error ("voronoi: minimum of 2 points needed"); endif ## Add box to approximate rays to infinity. For Voronoi diagrams the @@ -145,13 +143,26 @@ edges = edges(:, [(edges(1, 1 :end - 1) != edges(1, 2 : end) | ... edges(2, 1 :end - 1) != edges(2, 2 : end)), true]); - ## Eliminate the edges of the diagram representing the box - poutside = (1:rows (p)) ... - (p(:, 1) < xmin - xdelta | p(:, 1) > xmax + xdelta | ... - p(:, 2) < ymin - ydelta | p(:, 2) > ymax + ydelta); - edgeoutside = ismember (edges(1, :), poutside) & ... - ismember (edges(2, :), poutside); - edges(:, edgeoutside) = []; + if (numel (x) > 2) + ## Eliminate the edges of the diagram representing the box + poutside = (1:rows (p)) ... + (p(:, 1) < xmin - xdelta | p(:, 1) > xmax + xdelta | ... + p(:, 2) < ymin - ydelta | p(:, 2) > ymax + ydelta); + edgeoutside = ismember (edges(1, :), poutside) & ... + ismember (edges(2, :), poutside); + edges(:, edgeoutside) = []; + else + ## look for the edge between the two given points + for edge = edges(1:2,:) + if (det ([[[1;1],p(edge,1:2)];1,x(1),y(1)]) + * det ([[[1;1],p(edge,1:2)];1,x(2),y(2)]) < 0) + edges = edge; + break; + endif + endfor + ## Use larger plot limits to make it more likely single bisector is shown. + xdelta = ydelta = max (xdelta, ydelta); + endif ## Get points of the diagram Vvx = reshape (p(edges, 1), size (edges)); @@ -185,12 +196,18 @@ %! assert (vx(2,:), zeros (1, columns (vx)), eps); %! assert (vy(2,:), zeros (1, columns (vy)), eps); +%!testif HAVE_QHULL +%! ## Special case of just 2 points +%! x = [0 1]; y = [1 0]; +%! [vx, vy] = voronoi (x,y); +%! assert (vx, [-0.7; 1.7], eps); +%! assert (vy, [-0.7; 1.7], eps); + %% Input validation tests %!error voronoi () %!error voronoi (ones (3,1)) %!error voronoi (ones (3,1), ones (3,1), "bogus1", "bogus2", "bogus3") %!error <HAX argument must be an axes object> voronoi (0, ones (3,1), ones (3,1)) %!error <X and Y must be vectors of the same length> voronoi (ones (3,1), ones (4,1)) -%!error <minimum of 3 points needed> voronoi (2.5, 3.5) -%!error <minimum of 3 points needed> voronoi ([2.5, 3.5], [2.5, 3.5]) +%!error <minimum of 2 points needed> voronoi (2.5, 3.5)