Naming Scheme



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Naming Scheme

  

The name of each LAPACK routine is a coded specification of its function (within the very tight limits of standard Fortran 77 6-character names).

All driver and computational routines  have names of the form XYYZZZ, where for some driver routines the 6th character is blank.

The first letter, X, indicates the data type as follows:

 S     REAL
 D     DOUBLE PRECISION
 C     COMPLEX
 Z     COMPLEX*16 or DOUBLE COMPLEX

When we wish to refer to an LAPACK routine generically, regardless of data type, we replace the first letter by ``x''. Thus xGESV refers to any or all of the routines SGESV, CGESV, DGESV and ZGESV.

The next two letters, YY, indicate the type of matrix (or of the most significant matrix). Most of these two-letter codes apply to both real and complex matrices; a few apply specifically to one or the other, as indicated in Table 2.1.

 BD      bidiagonal
 GB      general band
 GE      general (i.e., unsymmetric, in some cases rectangular)
 GG      general matrices, generalized problem (i.e., a pair of general
         matrices) (not used in Release 1.0)
 GT      general tridiagonal
 HB      (complex) Hermitian band
 HE      (complex) Hermitian
 HG      upper Hessenberg matrix, generalized problem (i.e a Hessenberg and
         a triangular matrix) (not used in Release 1.0)
 HP      (complex) Hermitian, packed storage
 HS      upper Hessenberg
 OP      (real) orthogonal, packed storage
 OR      (real) orthogonal
 PB      symmetric or Hermitian positive definite band
 PO      symmetric or Hermitian positive definite
 PP      symmetric or Hermitian positive definite, packed storage
 PT      symmetric or Hermitian positive definite tridiagonal
 SB      (real) symmetric band
 SP      symmetric, packed storage
 ST      (real) symmetric tridiagonal
 SY      symmetric
 TB      triangular band
 TG      triangular matrices, generalized problem (i.e., a pair of triangular
         matrices) (not used in Release 1.0)
 TP      triangular, packed storage
 TR      triangular (or in some cases quasi-triangular)
 TZ      trapezoidal
 UN      (complex) unitary
 UP      (complex) unitary, packed storage

Table 2.1: Matrix types in the LAPACK naming scheme

When we wish to refer to a class of routines that performs the same function on different types of matrices, we replace the first three letters by ``xyy''. Thus xyySVX refers to all the expert driver routines for systems of linear equations that are listed in Table 2.2.

The last three letters ZZZ indicate the computation performed. Their meanings will be explained in Section 2.3. For example, SGEBRD is a single precision routine that performs a bidiagonal reduction (BRD) of a real general matrix.

The names of auxiliary routines  follow a similar scheme except that the 2nd and 3rd characters YY are usually LA (for example, SLASCL or CLARFG). There are two kinds of exception. Auxiliary routines that implement an unblocked version of a block algorithm have similar names to the routines that perform the block algorithm, with the sixth character being ``2'' (for example, SGETF2 is the unblocked version of SGETRF). A few routines that may be regarded as extensions to the BLAS are named according to the BLAS naming schemes (for example, CROT, CSYR).



next up previous contents index
Next: Driver Routines Up: Structure of LAPACK Previous: Data Types and




Tue Nov 29 14:03:33 EST 1994