Routine Naming Conventions

To call each routine from the FORTRAN 77 program, you can use the LAPACK name.

LAPACK names are listed in Table "Computational Routines for Systems of Equations with Real Matrices" and Table "Computational Routines for Systems of Equations with Complex Matrices", and have the structure ?yyzzz or ?yyzz, which is described below.

The initial symbol ? indicates the data type:

s	real, single precision
c	complex, single precision
d	real, double precision
z	complex, double precision

Some routines can have combined character codes, such as ds or zc.

The second and third letters yy indicate the matrix type and storage scheme:

ge	general
gb	general band
gt	general tridiagonal
dt	diagonally dominant tridiagonal
po	symmetric or Hermitian positive-definite
pp	symmetric or Hermitian positive-definite (packed storage)
pf	symmetric or Hermitian positive-definite (RFP storage)
pb	symmetric or Hermitian positive-definite band
pt	symmetric or Hermitian positive-definite tridiagonal
sy	symmetric indefinite
sp	symmetric indefinite (packed storage)
he	Hermitian indefinite
hp	Hermitian indefinite (packed storage)
tr	triangular
tp	triangular (packed storage)
tf	triangular (RFP storage)
tb	triangular band

The last three letters zzz indicate the computation performed:

trf	perform a triangular matrix factorization
trs	solve the linear system with a factored matrix
con	estimate the matrix condition number
rfs	refine the solution and compute error bounds
rfsx	refine the solution and compute error bounds using extra-precise iterative refinement
tri	compute the inverse matrix using the factorization
equ, equb	equilibrate a matrix.

For example, the sgetrf routine performs the triangular factorization of general real matrices in single precision; the corresponding routine for complex matrices is cgetrf.

Driver routine names can end with -sv (meaning a simple driver), or with -svx (meaning an expert driver) or with -svxx (meaning an extra-precise iterative refinement expert driver).

The Fortran 95 interfaces to the LAPACK computational and driver routines are the same as the FORTRAN 77 names but without the first letter that indicates the data type. For example, the name of the routine that performs a triangular factorization of general real matrices in Fortran 95 is getrf. Different data types are handled through the definition of a specific internal parameter that refers to a module block with named constants for single and double precision.