Math Forum Discussions

Moony Chou

Posts: 2
Registered: 8/3/11

Rubi 3 Usage?
Posted: Aug 2, 2011 11:54 PM

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When running current version of Rubi 3 from http://www.apmaths.uwo.ca/~arich/ on Mathematica 8, I find the web page lacks instructions for Rubi system. I tried Rubi in following steps and failed on few simple test problems from http://www.apmaths.uwo.ca/~arich/IntegrationTestHighlights/TestResultHighlights.html

Step 0. Modify some undefined functions in Rubi: "sin"->"Sin", "Sim"->"Simplify". There still exists some unknown functions in Rubi for me @_@

Step 1. Get(the Mathematica command) rule packages and utility package just in the order listed in http://www.apmaths.uwo.ca/~arich/IntegrationRules/MathematicaNotebookFiles/MathematicaNotebookFiles.html , my code is here: http://pastebin.com/nsLM4mMk

Step 2. Use the "Int" function provided by Rubi

However, some tests, even highlights tests meets the "$IterationLimit::itlim: Iteration limit of 4096 exceeded. " and return something like "Hold[Int[Rubi`Private`v$4716, x]]", and still exceed when I set $IterationLimit to 20000. Some highlight tests we cannot run are here: http://pastebin.com/u7EP4uPJ

I wonder the failures can be caused by following reasons:
* Since the rules associate with Int are matched in order according to the order they are Geted, the Get order might essential for right results.
* Existence of some undefined functions can lead to unknown results. "Sim", "ExpnExpand" etc. are not defined anywhere, I guess something are missed transferring from Rubi 2?

Does anyone meet similar problems?

P.S. I and some of my friends are trying to bring out a symbolic integration system by integrate the Albi (our nickname for Algorithm Based Integrator) and Rubi. We are working on replace our old rule based system with Rubi 3.