How to find graph intersections

[Kriek]

Hello,

I need to find the x values of intersections of the two graphs in the code below and put them in an array. I'm having a hard time trying to figure out how to do it. Any help would be much appreciated.

Thanks. 

[altenbach]

Can you place reasonably default values into the controls and repost (or simply tell us typical values for ponts, bessel number, and delta).

Some suggestions:

• You recalculate the same formulas with the same inputs millions of times per seconds. The calcuations only need to be done once and then whenever the inputs change. Use an event structure or at least place a small delay inside the while loop.
• The terminals for delta and bessel number belong before the FOR loop. They only need to be read once and not with every iteration of the FOR loop.
• ...

[Kriek]

yeah here's the one with values

Message Edited by Kriek on 05-23-2009 07:50 PM

[altenbach]

Here's a quick draft making a few simplifying assumptions (it will e.g. fail for cases where the two curves touch, but not cross. It also assumes that the red curve starts above the white curve). It probably still need a few tweaks, depending how general a solution you want. The solution is approximate, because in interpolates linearly between actual data points. Still, the two curves differ only by ~1E-15 or less at the found points. Modify as needed.

[Kriek]

thanks so much thats exactly what I needed to do.

[Cory_K]

Altenbach, nice job with marking the intersection points.

1 Kudos for you

[altenbach]

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altenbach wrote:
It probably still need a few tweaks ... 

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The VI currently goes into an infinite loop if the bessel number is set to zero. Not good!

The quickest fix would be th add a "+1" after "round to +inf" and eliminate the "-1" of the blue wire going into the while loop.