[Trilinos-Users] Amesos UMFPACK

Dave Makhija makhijad at colorado.edu
Fri Apr 16 18:24:38 MDT 2010


I attempted compiling UMFPACK with these flags in UFconfig.mk to solve
larger problems,

UMFPACK_CONFIG = -DLP64

and later

UMFPACK_CONFIG = -DLP64 -DLONGBLAS=long

After recompiling Trilinos neither fixed the problem. Am I missing some
other flags? How does this not run into the problem Mike H explained?

Thanks for the responses

Dave M






On Fri, Apr 16, 2010 at 5:28 PM, Matt G <mgoodman at email.arizona.edu> wrote:

> Optionally you can compile UMFPACK with the the -DP64 flag.  Its in the
> UMFPACK docs somewhere, but I mention it here<http://craneium.net/index.php?option=com_content&view=article&id=78>.
> Things get slower and these sorts of problems memory requirements grow with
> DOF^2 or so, so it wont buy you as much as it seems.
> --Matthew Goodman
>
> =====================
> Find me on LinkedIn: http://tinyurl.com/d6wlch
> Follow me on twitter: http://twitter.com/meawoppl
>
>
>
> On Fri, Apr 16, 2010 at 1:25 PM, Heroux, Mike <MHeroux at csbsju.edu> wrote:
>
>>  Dave,
>>
>>
>>
>> The restriction you see on problem size is due to the underlying size
>> restriction imposed by the Epetra data classes that are used with Amesos.
>> These classes use int as the data type, restricting problem sizes to 2^31.
>>
>>
>>
>> A new effort is underway to develop the same capabilities using Tpetra.
>> Tpetra uses a template parameter to specify the integer size, and so can use
>> any legitimate ordinal type that compiles correctly as the template
>> parameter, including 64 bit ints (and 32, 16 bits, or even 8-bit chars).
>> Tpetra supports generic scalar types in a similar way, e.g., float, double
>> complex<>.
>>
>>
>>
>> Using Tpetra, we can support any of  the variety of third-party sparse
>> direct solvers for all integer and scalar types.  In addition, we are
>> working on a templated version of KLU (the native default solver in Amesos)
>> that will allow us to support direct solution methods with any legitimate
>> ordinal and scalar types, including important cases such as doubledouble and
>> quaddouble (where the mantissa is two and four times as wide as double,
>> resp).
>>
>>
>>
>> We plan to have a working core of these capabilities done for the Fall
>> 2010 release of Trilinos.
>>
>>
>>
>> Best regards,
>>
>>
>>
>> Mike
>>
>>
>>
>> *From:* trilinos-users-bounces at software.sandia.gov [mailto:
>> trilinos-users-bounces at software.sandia.gov] *On Behalf Of *Dave Makhija
>> *Sent:* Friday, April 16, 2010 2:25 PM
>> *To:* trilinos-users at software.sandia.gov
>> *Subject:* [Trilinos-Users] Amesos UMFPACK
>>
>>
>>
>> I'm having trouble solving large linear systems using UMFPACK in Trilinos
>> when the same system can be solved with Matlab's UMFPACK with no problem.
>> The error returned is "Out of Memory", but this happens when 20% of our
>> memory resources are being used. Here is the problem:
>>
>>
>>
>> UMFPACK 5.4 documentation lists their naming convention for user callable
>> routines as,
>>
>>
>>
>> "1. umfpack di *: real double precision, int integers.
>>
>> 2. umfpack dl *: real double precision, UF long integers.
>>
>> 3. umfpack zi *: complex double precision, int integers.
>>
>> 4. umfpack zl *: complex double precision, UF long integers."
>>
>>
>>
>> The UMFPACK documentation also talks about compiling options for 32 bit or
>> 64 bit UMFPACK and says,
>>
>> "In the LP64 [64 bit] mode, the umfpack_dl_* and umfpack_zl_* routines can
>> solve huge problems (not limited to 2GB), limited of course by the amount of
>> available memory."
>>
>>
>>
>> However, in trilinos-10.2.0-Source/packages/amesos/src/Amesos_Umfpack.cpp
>> it clearly uses only the umfpack_di* (32 bit, 2GB max) routines.
>>
>>
>>
>> So the entire interface to the UMFPACK solver is hard coded to only do
>> relatively small problems (2GB max)? Are there any releases or workarounds
>> that can use the 64 bit UMFPACK routines (umfpack_dl_*)? I'm not sure how
>> much work it would be to convert it myself, but I'm guessing if it's not
>> included in Amesos already that it would be relatively hard to change.
>>
>> _______________________________________________
>> Trilinos-Users mailing list
>> Trilinos-Users at software.sandia.gov
>> http://software.sandia.gov/mailman/listinfo/trilinos-users
>>
>>
>
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