FLSG620DA Users' Note | http://www.csar.cfs.ac.uk/test/software/maths/nag/mark20... |
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 | constants, e.g. | - | DCONJG |
e in | - D, e.g. | ||
e in | formats, e.g. e12.4 | - D, e.g. D12.4 | |
All references to routines in Chapter F07 - Linear Equations (LAPACK) and Chapter F08 -
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,
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