General Information

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Legacy Libraries on NY Blue/L

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NOTE: There is an applications web page listing applications available on NY Blue/L beyond the libraries described here.

So also see that applications page.


Basic Linear Algebra Subprograms (BLAS)

The Basic Linear Algebra Subprograms (BLAS) are routines that provide standard building blocks for performing basic vector and matrix operations. The archive libblas.rts.a has been compiled from the f77 source code downloaded from:

    blrts_xlf  -O3 -qhot -qarch=440 -qtune=440 -qmaxmem=-1 -qstrict  

To link against the BLAS library add the following at the link step:

   -L/bgl/local/lib -lblas.rts   

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Basic Linear Algebra Communication Subprograms (BLACS)

The Basic Linear Algebra Communication Subprograms (BLACS) provide a linear algebra oriented message passing interface. The archives have been compiled from the source code downloaded from:

For Fortran, to link with the BLACS libraries add the following at your link step:

   /bgl/local/lib/blacsF77init_MPI-BGL-0.a 
   /bgl/local/lib/blacs_MPI-BGL-0.a 
   /bgl/local/lib/blacsF77init_MPI-BGL-0.a  

For C, to link with the BLACS libraries add the following at your link step:

   /bgl/local/lib/blacsCinit_MPI-BGL-0.a 
   /bgl/local/lib/blacs_MPI-BGL-0.a 
   /bgl/local/lib/blacsCinit_MPI-BGL-0.a 

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Linear Algebra Package (LAPACK)

The LAPACK library contains routines for solving systems of simultaneous linear equations, least-squares solutions of linear systems of equations, eigenvalue problems, and singular value problems. The associated matrix factorizations (LU, Cholesky, QR, SVD, Schur, generalized Schur) are also provided, as are related computations such as reordering of the Schur factorizations and estimating condition numbers. Dense and banded matrices are handled, but not general sparse matrices. In all areas, similar functionality is provided for real and complex matrices, in both single and double precision.

To link against the lapack library, add the following at the link step:

-L/bgl/local/lib -llapack.rts

Additional Information

  • Many LAPACK routines invoke BLAS routines.
    To link against the LAPACK library and the BLAS routines in ESSL:
    -L/bgl/local/lib -L/opt/ibmmath/lib -llapack.rts -lesslbg
  • To link against the LAPACK library and the BLAS routines from netlib (described above):
    -L/bgl/local/lib -llapack.rts -lblas.rts
  • The ESSl library contains BLAS routines, is tuned specifically for Blue Gene, and can help significantly in improving performance.
  • But be aware that ESSL does not contain all of the standard BLAS routines.
  • Information about LAPACK including a hyperlink to LAPACK USER'S GUIDE

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Engineering and Scientific Subroutine Library (ESSL)

IBM's ESSL for SLES on POWER (v4.2.5) that supports Blue Gene/L has been installed on the Front-End Node. ESSL provides over 150 math subroutines (Linear Algebra, Matrix operations, Sorting and Searching, FFT, Random Number Generator, etc.) that have been specifically tuned for performance on BG/L.

ESSL subroutines are for Serial code. Parallel ESSL (PESSL) in not available on the Blue Gene/L. SCALAPAC provides parallel subroutines available on the Blue Gene/L.

The ESSL routines have been installed on the Front-End host under /opt/ibmmath/lib and the header files under /opt/ibmmathc/include. Thus, to link your code to the ESSL library you should use (Fortran):
blrts_xlf example.f -L/opt/ibmmath/lib -lesslbg

Information on the ESSL subroutines is available on the command line of the Front-End host using the installed man pages. For example, to obtain a description of the subroutine sasum, type: man sasum

Additional Information

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Mathematical Acceleration Subsystem (MASS) for Blue Gene/L

Mathematical Acceleration Subsystem (MASS) for Blue Gene/L consists of libraries of mathematical intrinsic functions tuned specifically for optimum performance on Blue Gene/L. These libraries offer improved performance over the standard mathematical library routines, are thread-safe, and support 32-bit compilations in C, C++, and Fortran applications.

MASS v4.4 (scalar and vector) libraries has been installed on the Front-End node under: /opt/ibmcmp/xlmass/bg/4.4/. The subdirectory blrts_lib contains the "cross-compiled" versions of the libraries. The lib and lib64 subdirectories contain the "native" versions (for executables that will run on the Front-End node, not on the Blue Gene Compute Nodes).

Chapter 3 of the Using the XL Compilers for Blue Gene Guide (pdf) provides detailed instructions on how to compile and link your code to the MASS libraries.

Add linker option -Wl,--allow-multiple-definition to allow multiple definitions for the math routines.

Additional Information

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