Did you begin by loading ~addons/math/mt/mt.ijs ?  --Kip Murray

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On Apr 8, 2013, at 10:51 AM, Devon McCormick <[email protected]> wrote:

> I attempted to use one of the math/mt routines (geev) but get a value error
> on "trsmu1x" which  does not appear to be defined anywhere.
> 
> There is a Jacobi solver in ~addons/math/misc/jacobi that appears to work
> for a symmetric argument.  Also, there's the code from Donald McIntyre's
> article on Jacobi's method -
> http://www.jsoftware.com/jwiki/DevonMcCormick/JacobiByMcIntyre - which I
> modernized to run in contemporary J - that appears to give an answer when
> the other version of "jacobi" does not (i.e. for a non-symmetric matrix)
> but I don't know how good this is.  I can use this latter to duplicate the
> results shown here -
> http://algebra.math.ust.hk/eigen/01_definition/lecture2.shtml - for some
> simple, small problems.
> 
> 
> On Mon, Apr 8, 2013 at 3:17 AM, Kip Murray <[email protected]> wrote:
> 
>> Igor Zhuravlof provides j routines that model LAPACK routines for
>> eigenvalues and eigenvectors.  See "matrix toolbox"
>> 
>> ~addons/math/mt
>> 
>> with contents summarized in
>> 
>> ~addons/math/mt/mt.ijs
>> 
>> I have not tried them but would expect them to run in j701JHS.
>> 
>> --Kip Murray
>> 
>> 
>> On 4/8/2013 12:45 AM, Michal D. wrote:
>> 
>>> Hi All,
>>> 
>>> I have been trying to get J to compute the eigen values & vectors of a
>>> matrix.  I've come across
>>> http://www.jsoftware.com/**jwiki/Essays/Eigenvaluesbut<http://www.jsoftware.com/jwiki/Essays/Eigenvaluesbut>none
>>>  of the
>>> algorithms there seem stable on my input matrix and the
>>> lapack package doesn't seem to work on 64-bit J.  I laboriously exported
>>> the matrix to a .csv and then hacked up a C++ program that computes the
>>> eigen values using eigen (
>>> http://eigen.tuxfamily.org/**index.php?title=Main_Page<http://eigen.tuxfamily.org/index.php?title=Main_Page>)
>>> which had no problem
>>> with computing the eigen values.
>>> 
>>> What is the current state-of-the-art in eigen values in J?  Should I just
>>> downgrade to 32-bit J and use the lapack package?
>>> 
>>> Cheers,
>>> 
>>> Mike
>>> 
>>> 
>>> Ps. There is nothing I like better than generating random input data using
>>> J.  What took pages of Haskell and TCL was boiled down to 7 clear lines of
>>> J.  WOW =)
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> 
> 
> 
> -- 
> Devon McCormick, CFA
> ^me^ at acm.
> org is my
> preferred e-mail
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