Re: Looking for gen symm sparse eigensolver in C or C++
From: Madhusudan Singh (spammers-go-here_at_spam.invalid)
Date: 03/28/05
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Date: Mon, 28 Mar 2005 12:19:25 -0500
carlos@colorado.edu wrote:
>> Returning to your OP, look at arpack++. I have heard that it is
> written in
>> C++, but the I do not know how well tested it is. Caveat Emptor.
>
>
> The eigensolver is to be coupled to a volume acoustic analyzer based on
> C++ libraries. These do mesh generation, ray tracing, graphics, GUI,
> etc. Target 10^5 to 10^6 freedoms, about 1K-5K eigenmodes needed. The
> C++ code is there and wont be touched.
>
Trying to do the frills (which can all be done in Fortran - gnuplotfortran /
dislin / winteracter / gino are all tools for this kind of work) in C++
when the heart of your program is best done in Fortran is a very bad design
choice to start with. However, as you described, it does not seem that
logic is a particularly strong consideration for the powers-that-be.
I wish you the best.
> Seems like a good fit for arpack or block-lanczos although it is the
> generalized eigenproblem, not the standard one. Both matrices are
> singular. arpack++ is a good suggestion; I didnt know it existed.
> Is it an ongoing project?
I have no idea. I remember seeing it on an ftp site a long time ago and
reading a little bit of the README.
I have never tried it and do not know how well-tested it is (unlike the f77
arpack library which I used a lot for a while).
>
> If only f77 eigensolvers are available, C++/f77 wrappers would be
> required. That always brings the chance of compiler and library
> conflicts (e.g. I/O libraries). Intermix conflicts are best avoided if
> the implementer is proficient in both languages and compilers, but that
> is not the case here.
Using Fortran calls in C/C++ code is trivial (I have heard good things about
cfortran.h), as is using C in Fortran. Calling C++ from Fortran is usually
messy. As long as you have the latest libc libraries with gcc/g77, I do not
think it ought to matter. But you obviously know more about your situation
than the content of your post conveys.
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