Response #1: 2005-09-12

General

1. Is dense linear algebra a performance bottleneck in your applications?
Yes

2. How often do your applications use the arithmetic precisions listed below:

3. What dense matrix sizes are most important or time-consuming for your application?
100,000s X 100,000s

4. Does your application come close to, or run out of memory on important problems?
Yes

5. Number of processors used for your application:

6. Which architectures do you use or intend to use in the next three years?
Multi-core-thread, Vector-computers, Distributed-memory, Hybrid-shared

7. Do you use any other sequential or parallel dense linear algebra packages other than LAPACK or ScaLAPACK?
NAG, IMSL, ESSL (IBM), ASL (NEC)

8. Please rank how the following features would be useful to your current or planned applications?

9. Do your applications solve linear algebra problems of the type?
Linear positive definite systems, Banded linear systems, General linear systems, Generalized eigenvalue, Symmetric eigenvalue, Non-symmetric eigenvalue

LAPACK Usage

1. Do you use LAPACK (or a vendor version of LAPACK )?
Yes

3. If using another package, which one(s)?
NAG, IMSL, ESSL (IBM), ASL (NEC)

4. If you use LAPACK, do you use a vendors version or one obtained directly from Netlib?
Vendor, Netlib

5. If you have used both a vendors version of LAPACK and Netlibs, how do the two versions compare?
Vendor's version is used for performance and netlib's one for portability.

6. Do your applications make direct LAPACK calls?
Yes

7. Do your applications use libraries which depend on LAPACK?
Yes

8. Do your applications use a higher-level interface to LAPACK?
No

10. Is the LAPACK procedure interface a barrier to more extensive use?
Yes

11. From which languages do you call LAPACK routines?
C, Fortran 77, Fortran 90/95, Fortran 2003

12. Please describe any tools or helper functions that you frequently implement to assist your applications in using LAPACK?
PMD (Parallel multi-domain Decomposition), see : http://www.idris.fr/data/publications/PMD

13. How could the LAPACK interface be improved to feel more natural to your application and implementation language?
With fortran 95 and even more with Fortran 2003 many things could be improved using the new functionnalities as MODULE, genericity, optional arguments, dynamic allocation of Fortran 2003 and its object oriented programming and C-Fortran compatibility.

14. If you have installed LAPACK yourself, how could the installation process be improved?
Installation is not a problem.

15. How frequently do you refer to the LAPACK Users Guide?
Frequently

16. What information in the LAPACK guide is hard to find or is missing, if any?
Always found what I need.

ScaLAPACK Usage

1. Do you use ScaLAPACK (or a vendor version of ScaLAPACK )?
Yes

3. If using another package, which one(s)?
PESSL (IBM)

4. If you use ScaLAPACK, do you use a vendors version or one obtained directly from Netlib?
Vendor

5. If you have used both a vendors version of ScaLAPACK and Netlibs, how do the two versions compare?
As for LAPACK, vendor's version is used to reach optimal performance and netlib's one for portability.

6. Do your applications make direct ScaLAPACK calls?
Yes

7. Do your applications use libraries which depend on ScaLAPACK?
No

8. Do your applications use a higher-level interface to ScaLAPACK?
No

10. Is the ScaLAPACK procedure interface a barrier to more extensive use?
Yes

11. From which languages do you call ScaLAPACK routines?
C

12. Please describe any tools or helper functions that you frequently implement to assist your applications in using ScaLAPACK?
PMD (Parallel multi-domain Decomposition), see : http://www.idris.fr/data/publications/PMD

13. How could the ScaLAPACK interface be improved to feel more natural to your application and implementation language?
The key problem of using ScalaPACK (as others similar libraries) is data distribution. Block cyclic distribution is usually hard to stick on during a calculation. Perhaps, enriching the type of data distribution or letting users define/describe their own data distribution could be a more natural way (but at what cost ?).

14. If you have installed ScaLAPACK yourself, how could the installation process be improved?
May be using a configure like installation can let people avoid the configuration by hand of the Bmake.inc file. This means automatic configuration of the C-Fortran calling interface and the MPI implementation for example.

15. How frequently do you refer to the ScaLAPACK Users Guide?
Frequently

16. What information in the ScaLAPACK guide is hard to find or is missing, if any?
A clear description of the procedures and their arguments with lots of examples.

Targeted Environment Specifics

1. Under which operating system environments do your applications run?
AIX, Linux, Unicos, NEC

2. If your applications run in a shared-memory environment, which styles of parallelism do they employ?
Platform threading

Additional Information