The LAPACK initiative seems to have got a bit marooned. It looks as
if the latest version, LAPACK 3.0+ (?), dates from Summer 2000. The
intros mention that the package was optimised in Fortran - and a
subroutine set BLAS preferably to be optimised on target machines -
and there are developments in Java, C (as we knew), C++ etc.
There's a remark in "http://www.netlib.org/lapack++/"; that
"Lapack++ has been superseded by the Template Numerical Toolkit (TNT)
<http://math.nist.gov/tnt/>, which
utilizes new features of the ANSI C++ specification. TNT is a new
design, but will
integrate the functionality of lapack++, IML++
<http://math.nist.gov/iml++/>, SparseLib++
<http://math.nist.gov/sparselib++/>, and mv++
<http://math.nist.gov/mv++/>."
Another can of worms?
Assuming LAPACK is still required in view of these developments, I
wonder if it would be better to try to compile or get hold of a
Fortran-sourced dll than use the C translation which presumably
loses some of the benefit of all that optimisation, but perhaps
the J to Fortran linkage is too difficult. (My own Ftn compiler
is Salford's F90 (was F77) and I've never managed to link it to
J or APL!)
Anyway, I did discover a seemingly C-sourced dll more up to date
than the one I've previously used for J in windows; it's embedded
in (look out for line breaks)
"http://sourceforge.net/project/showfiles.php?group_id=4511&package_id=4518&release_id=191000";
within a "matlisp" package. There's also a blas.dll . There are
over 800 .f files (eg dgeev.f) which suggests that number of fortran
subroutines greater than the number, 541, of routine descriptions
in the old jlapack package (eg dgeev.lap). These files’ headers
provide suitable documentation. There also a host of lisp files
which are evidently cover functions in that language and evidently
not needed for jlapack.
I loaded these dlls into j601\addons\lapack, renamed lapack.dll as
jlapack.dll and tried the LAPACK studio; it seems to work! I don’t
know if blas.dll is necessary; it doesn’t seem to be used for
dgeev, but might be necessary for other work.
Mike
John Randall wrote:
Many questions about LAPACK are answered at
http://www.netlib.org/lapack/faq.html
There are prebuilt binaries for some architectures at
http://www.netlib.org/lapack/archives/
Whether these need additional tweaking to work with J, I don't know: if
not, it is probably better to let the netlib people do the work.
Best wishes,
John
Eric Iverson wrote:
Quick comment: the lapack distributed with J Windows was built from lapack
source from several years ago. There have been serveral updates to the
source since then. Unix Lapack tends to be part of of the distribution and
is likely more current. Perhaps we (Jsoftware) should distribute a more
current windows lapack, but this is probably an area where user
contribution
would be a better route. That is, someone with interest and knowledge
should
build a current Windows Lapack (assuming this isn't simply a matter of
providing a pointer to someone else who already does this) and provide the
links and downloads.
----- Original Message -----
From: "John Randall" <[EMAIL PROTECTED]>
To: "Programming forum" <[email protected]>
Sent: Friday, March 03, 2006 7:16 AM
Subject: Re: [Jprogramming] LAPACK question: principal eigenvector
There do seem to be slight variations between results from the Windows
and
Linux versions of LAPACK. They are mathematically insignificant, but
have
an effect if you are erroneously relying on order of results. Here's my
revised code for calculating a principal eigenvector using LAPACK.
require '~addons/lapack/lapack.ijs'
require '~addons/lapack/dgeev.ijs'
la=:3 : 0
'l c r'=.dgeev_jlapack_ y.
({. \: c){"1 r
)
und=: >(1,1,5);(1,1,3);((%5),(%3),1) NB. "Understandability
(%+/)power und
0.48064 0.405388 0.113972
%+/)la und
0.48064 0.405388 0.113972
Best wishes,
John
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