[Plplot-devel] Re: plsurf() bugs

[<jc...@fe...>]

On Thursday 17 October 2002 18:27, Jo=E3o Cardoso wrote:
| On Thursday 17 October 2002 05:16, Alan W. Irwin wrote:
| | On Wed, 16 Oct 2002, Alan W. Irwin wrote:
=2E..

| | Joao, I have noticed one final plsurf3d core bug that shows up for
| | all front ends and which detracts from the appearance of the
| | surface contours; those contour lines are sometimes broken (page 6
| | for example).
|
| I supose you are refering to the contour drawn at the surface, using
| the rosenbrock function?
|
| If you mean the sombrero like function, than try to magnify the
| broken contour line using the tk driver. The contour is there!
|
| If you mean the rosenbrock function, and you mean that some contour
| lines in the deep valeys are broken, remember that you are watching
| just the face of the valey that is visible... thus you can only see
| part of the contour.
|
| To make the valeys more visible, you can try to increase the number
| of points, XPTS and YPTS. I did it and got a core dump!!! One more
| bug to solve.

That was easy. But one can't see better the deep valeys from the top=20
(shouldn't we call them "holes" instead of valleys?).
Anyway they are there.

Joao

| |  You comment in the code that the surface contours are
| | simple minded.  Does that mean it will be difficult to fix the
| | broken surface contour problem?

As I said , I don't think they are broken. When I said the algorithm was=20
simple minded (and it is, but it does not mean it is not effective), I=20
meant that the contour lines could be jagged, as there is no=20
interpolation nor smoothing done...
It is possible to use the information from the countour lines drawn at=20
the base xy plane, but that would make the plot much more lengthy than=20
it already is; I think, I didn't tried it.

Joao