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Colors on contour plots showing wrong.

SOLVED

Re: Colors on contour plots showing wrong.

Valery Ochkov wrote:

Sometimes when I prepare a picture from Mathcad for an article or a book I manual correct a counter plot in Paint for example.

Good idea but it shouldn't be necessary.

Unfortuneately quality plot never were a strength of Mathcad, not even in Mathcad 15 and below and to obtain publication quality plots you woul either have to export the Mathcad plots and finish them in another program, as you suggest, or export the data and redo the whole plot with another tool (Origin, or even Excel will do better sometimes).

Re: Colors on contour plots showing wrong.

Vladimir, I was able to track down the error and created the attached sheet to demonstrate. Maybe helpful in communication with PTC technical support.

The sheet is in Prime2 format, but the error is thrown likewise in Prime3.

Maybe other people with different hardware/software can report if the error shows up for them.

So far the error showed up with both Prime2 and Prime 3 with

  • 32bit, WinXP, 1-2GB RAM
  • 32bit, Win7, 2GB RAM

It did not show with

  • 64bit, Win7, 4GB RAM

PrimeError.png

P.S.: I know I could have used the new clear() command to redim a and b.

Re: Colors on contour plots showing wrong.

As the way you constructed the matrices X and Y crashes Mathcad on some installations (see above: http://communities.ptc.com/message/226620#226620) I created X and Y in a different way an now no problems are experienced. Of course the colours Mathcad shows still are wrong.

I added a simple 2D linear interpolation of your data and now Mathcad is showing the colors as we had excpected (despite the fact the the colors chosen are somewhat unskilled, especially the different shades of cyan). Nevertheless the Excel result still is prettier ;-)

I would have thought that Mathcad would do that kind of interpolation itselft if told to plot the contours of a matrix rather than a function.

The attached file is in Prime2 format.

ContourPlot10kn_2.png

Re: Colors on contour plots showing wrong.

I am hoping that PTC may finally get the message. They do not seem to be listening.

Re: Colors on contour plots showing wrong.

Being curious I recreated the plot with MC 15 and here we don't have the wrong colors when plotting contour plots of matrices. We lack the color legend, though and would have to add it by creating a second plot underneath.

contour.png

Highlighted

Re: Colors on contour plots showing wrong.

Werner, this is excellent! It looks good too, apart from those two yellow colour bands that are very similar to each other. I had assumed that interpolation would not be required in plotting this as the data is already smooth enough, but you were right to give it a try. Many thanks!

Re: Colors on contour plots showing wrong.

It looks good too, apart from those two yellow colour bands that are very similar to each other.

Unfortunately we have no control over the colors unlike as in Mathcad 15 where we can chose from different colormaps and may even create our own.

I had assumed that interpolation would not be required in plotting this as the data is already smooth enough, but you were right to give it a try.

It should work without explicit interpolation - I would call that a bug in Prime.

We see that no interpolation is necessary in MC15.

Primes algorithm fails at the ends of the spectrum.

Re: Colors on contour plots showing wrong.

That is odd. I created a 3-column matrix of the points, put it on the contour plot, and got a pretty good plot without having to interpolate. Not sure why the original method didn't work.

Re: Colors on contour plots showing wrong.

Nice approach and good to see that it works that way.

Nevertheless it should work the way it was originally setup with the three matrices as well. As it worked that way in MC15 I would call it a newly introduced bug which should be adressed in the next release.

The same is true of course for the severe bug where Prime crashes on 32bit system by using a simple operation with not that big vectors (http://communities.ptc.com/message/226620#226620)

Hope someone will be willing to report these two bugs to R&D.

Re: Colors on contour plots showing wrong.

Hi Roger, I can't open your file. It says the file type is not supported. I have attached the log file with the error report. I am running Prime 2.0 with Datecode: M010 (2012.10.03.002/2.0.1.35).