BLAS1_S
Basic Linear Algebra Subprograms
Level 1
Single Precision Real Arithmetic

BLAS1_S is a library of C++ routines, using single precision real arithmetic, which implement the Level 1 BLAS, or Basic Linear Algebra Subprograms.

The BLAS are a small core library of linear algebra utilities, which can be highly optimized for various architectures. Software that relies on the BLAS is thus highly portable, and will typically run very efficiently.

The Level 1 BLAS are primarily for use in vector operations. In certain cases, they may also be used to operate on the rows or columns of a two-dimensional array.

On the SGI, a precompiled optimized BLAS library may be linked to via a command like:

g++ myprog.C -lblas

On the Compaq ALPHA, a precompiled optimized BLAS library is available in CXML, the "Compaq Extended Math Library". A C++ program can link with the CXML library, but the CXML routine names must have an underscore appended to them, and they must be declared as extern "C" to avoid the dreaded C++ name-mangling. The linking command would be something like:

g++ myprog.C -lcxml

Related Data and Programs:

BLAS1_C is a C++ library which is the single precision complex arithmetic version of BLAS1.

BLAS1_D is a C++ library which is the double precision real arithmetic version of BLAS1.

BLAS1_S is also available in a C version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version.

BLAS1_Z is a C++ library which is the double precision complex arithmetic version of BLAS1.

BLAS2 is a FORTRAN90 library which is the Level 2 BLAS, for matrix-vector operations.

BLAS3 is a FORTRAN90 library which is the Level 3 BLAS, for matrix-matrix operations.

GSL is the Gnu Scientific Library which includes an implementation of the BLAS1 routines.

LAPACK is a FORTRAN90 library of linear algebra routines that uses BLAS1 routines

LINPACK is a C++ linear algebra library that uses the BLAS1 routines

SUPER_BLAS is a C library which is a version of some of the BLAS1 routines.

Reference:

1. Jack Dongarra, Jim Bunch, Cleve Moler, Pete Stewart,
   LINPACK User's Guide,
   SIAM, 1979,
   ISBN13: 978-0-898711-72-1,
   LC: QA214.L56.
2. Charles Lawson, Richard Hanson, David Kincaid, Fred Krogh,
   Algorithm 539, Basic Linear Algebra Subprograms for Fortran Usage,
   ACM Transactions on Mathematical Software,
   Volume 5, Number 3, September 1979, pages 308-323.
3. Thomas Coleman and Charles Van Loan,
   Handbook for Matrix Computations,
   Society for Industrial and Applied Mathematics,
   3600 University City Science Center,
   Philadelphia, PA 19104-2688.
4. Compaq Computer Corporation,
   Compaq Extended Math Library,
   CXML Reference Guide

Source Code:

• blas1_s.C, the level 1 BLAS in single precision real arithmetic.
• blas1_s.H, an include file for BLAS1_S.
• blas1_s.csh commands to compile the BLAS1_S.

Examples and Tests:

• blas1_s_prb.C, the calling program.
• blas1_s_prb.csh compiles, links and runs the calling program.
• blas1_s_prb.out the resulting output file.

List of Routines:

• I4_MAX returns the maximum of two integers.
• I4_MIN returns the smaller of two integers.
• ISAMAX finds the index of the float vector element of maximum absolute value.
• LSAME returns TRUE if CA is the same letter as CB regardless of case.
• R4_ABS returns the absolute value of a float.
• R4_MAX returns the maximum of two floats.
• R4_SIGN returns the sign of a float.
• SASUM takes the sum of the absolute values of a float vector.
• SAXPY computes float constant times a vector plus a vector.
• SCOPY copies a float vector X to a vector Y.
• SDOT forms the dot product of two float vectors.
• SMACH computes machine parameters of float arithmetic.
• SNRM2 returns the euclidean norm of a float vector.
• SROT applies a float plane rotation.
• SROTG constructs a float Givens plane rotation.
• SSCAL scales a float vector by a constant.
• SSWAP interchanges two float vectors.
• XERBLA is an error handler for the LAPACK routines.

You can go up one level to the C++ source codes.