FLSG620DA Users' Note
http://www.csar.cfs.ac.uk/test/software/maths/nag/mark20...
4 of 10
18/08/2004 12:11
returned by X02AJF in
Section 4
Thus a parameter described as
real
should be declared as DOUBLE PRECISION in your
program. If a routine accumulates an inner product in
additional precision
, it is using software
to simulate quadruple precision.
In routine documents that have been newly typeset since Mark 12 additional bold italicised
terms are used in the published example programs and they must be interpreted as follows:
real
as an intrinsic function name - DBLE
imag
- DIMAG
cmplx
- DCMPLX
conjg
- DCONJG
e
in constants, e.g. 1.0
e
-4 - D, e.g. 1.0D-4
e
in formats, e.g.
e
12.4 - D, e.g. D12.4
All references to routines in Chapter F07 - Linear Equations (LAPACK) and Chapter F08 -
Least-squares and Eigenvalue Problems (LAPACK) use the LAPACK name, not the NAG
F07/F08 name. The LAPACK name is precision dependent, and hence the name appears in a
bold italicised typeface.
The typeset examples use the single precision form of the LAPACK name. To convert this name
to its double precision form, change the first character either from S to D or C to Z as
appropriate.
For example:
sgetrf
refers to the LAPACK routine name - DGETRF
cpotrs
- ZPOTRS
3.4. Explicit Output from NAG Routines
Certain routines produce explicit error messages and advisory messages via output units which
either have default values or can be reset by using X04AAF for error messages and X04ABF for
advisory messages. (The default values are given in
Section 4
). The maximum record lengths of
error messages and advisory messages (including carriage control characters) are 80 characters,
except where otherwise specified. These routines are potentially not thread safe and in general
output is not recommended in a multithreaded environment.
3.5. Interface Blocks
The NAG Fortran Library Interface Blocks define the type and arguments of each user callable
NAG Fortran Library routine. These are not essential to calling the NAG Fortran Library from
Fortran 90 programs. Their purpose is to allow the Fortran 90 compiler to check that NAG
Fortran Library routines are called correctly. The interface blocks enable the compiler to check
that:
(a) Subroutines are called as such
(b) Functions are declared with the right type
(c) The correct number of arguments are passed
(d) All arguments match in type and structure
These interface blocks have been generated automatically by analysing the source code for the
NAG Fortran Library. As a consequence, and because these files have been thoroughly tested,
