Two-Dimensional Newton-Raphson Root Finder

[Eufto]

I'm trying to develop a two-dimensional newton-raphson root finder for two equations, two variables. so far, i haven't been able to find anyone else who has attempted to do this in labview, but if anyone has any ideas or suggestions, they'd be greatly appreciated.

the equations i'd like to solve have multiple elliptic integrals of different kinds that also include the two variables. this seems to complicate the matter further. hence, i have found labview cannot do partial derivatives of functions that contain such integrals. again, thanks for any help/insight you can offer!

[Jeremy_L]

Hi,

There is an example program available that demonstrates finding the roots with Newton-Raphson and Ridders algorithms on our website.

Link [link removed; example no longer available]

Also, there was a discussion forum thread about this a while back:

Thread [link removed; thread no longer available]

Hope this helps!

Jeremy L.
National Instruments

[Eufto]

Jeremy -- thanks for the reply, but i did check out the example program for NR and Ridders, but the complication with my need is that the NR algorithm discussed is single dimensional and is unable to handle more complex functions such as integrals within the two equations that need to be solved. the implementation of a single variable NR is quite simple compared to those of n-dimensions because of you are then required to calculate the jacobian of the n-dimensional matrices. wud u have any suggestions.

[Jeremy_L]

Hi,

After some googling, I would take a look at this pdf file, pages 381-382. It talks about doing the NRM for Nonlinear Systems of Equations. In this paper, there lies some C++ code that I believe you can translate into LabVIEW. But at this point, we don't have anything native to do this, and so I would highly encourage you to write this (if you have the time and resources), submit it as example code to NI, and also write a product suggestion to us at the Product Suggestion Center. I think this is the best bet for you, unless you can find some dll that has the function defined already. Th
en, you can call the DLL from LabVIEW. Hope this helps!

Jeremy L.
National Instruments