NAG recommends that you read the following minimum reference material before calling any library routine:
(a) Essential Introduction
(b) Chapter Introduction
(c) Routine Document
(d) Implementation-specific Users' Note
Items (a), (b) and (c) are included in the NAG Fortran Library Manual; items (a) and (b) are also included in the NAG Fortran Library Introductory Guide; item (d) is this document which is provided in both HTML form and plain text form. Item (a) is also supplied in plain text form.
FORTRAN <program>or, if using Digital Fortran 90, type
F90 <program>where <program> is the name of a .FOR file containing your program.
To link a program with the NAG Library, assuming that the library has been associated with a LNK$LIBRARY logical, type
LINK <program>where <program> is the name of a .OBJ file containing your compiled program.
An options file should be used if linking to a shareable image, e.g.
LINK <program>, NAG$LINK.OPT/OPTIONSwhere NAG$LINK.OPT contains the line NAG$SHARE/SHAREABLE.
To run the program, type
ASSIGN <data> FOR005 ASSIGN <results> FOR006 RUN <program>where <program> is the name of a .EXE file containing your linked program, <data> is data to be read from Fortran channel 5, and <results> are results to be written to Fortran channel 6.
In the NAG Fortran Library Manual, routine documents that have been typeset since Mark 12 present the example programs in a generalised form, using bold italicised terms as described in Section 3.3.
In other routine documents, the example programs are in single precision and require modification for use with double precision routines. This conversion can entail:
The example programs supplied to a site in machine-readable form have been modified as necessary so that they are suitable for immediate execution. Note that all the distributed example programs have been revised and do not correspond exactly with the programs published in the manual, unless the documents have been recently typeset. The distributed example programs should be used in preference wherever possible.
real - DOUBLE PRECISION (REAL*8)
basic precision - double precision
complex - COMPLEX*16
additional precision - quadruple precision (REAL*16)
machine precision - the machine precision, see the value
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. 1.0e-4 - D, e.g. 1.0D-4 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 - 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
See Section 5 for additional documentation available from NAG.
(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, they are more reliable than writing your own declarations.
The NAG Fortran Library Interface Block files are organised by Library chapter. The module names are:
NAG_F77_A_CHAPTER NAG_F77_C_CHAPTER NAG_F77_D_CHAPTER NAG_F77_E_CHAPTER NAG_F77_F_CHAPTER NAG_F77_G_CHAPTER NAG_F77_H_CHAPTER NAG_F77_M_CHAPTER NAG_F77_P_CHAPTER NAG_F77_S_CHAPTER NAG_F77_X_CHAPTERThese are supplied in pre-compiled form (.F90$MOD files). If, for example, NAG_F77_S_CHAPTER is required, it should be copied to the current directory, or to a directory specified by a /INCLUDE qualifier on the compile line.
In order to make use of these modules from existing Fortran 77 code the following changes need to be made:
These changes are illustrated by showing the conversion of the Fortran 77 version of the example program for NAG Fortran Library routine S18DEF. Please note that this is not exactly the same as the example program that is distributed with this implementation. Each change is surrounded by comments boxed with asterisks.
* S18DEF Example Program Text
* Mark 14 Revised. NAG Copyright 1989.
*******************************************************************
* Add USE statement for relevant chapters *
USE NAG_F77_S_CHAPTER
* *
*******************************************************************
* .. Parameters ..
INTEGER NIN, NOUT
PARAMETER (NIN=5,NOUT=6)
INTEGER N
PARAMETER (N=2)
* .. Local Scalars ..
COMPLEX*16 Z
DOUBLE PRECISION FNU
INTEGER IFAIL, NZ
CHARACTER*1 SCALE
* .. Local Arrays ..
COMPLEX*16 CY(N)
* .. External Subroutines ..
*******************************************************************
* EXTERNAL declarations need to be removed (and type declarations *
* for functions). *
C EXTERNAL S18DEF
* *
*******************************************************************
* .. Executable Statements ..
WRITE (NOUT,*) 'S18DEF Example Program Results'
* Skip heading in data file
READ (NIN,*)
WRITE (NOUT,*)
WRITE (NOUT,99999) 'Calling with N =', N
WRITE (NOUT,*)
WRITE (NOUT,*)
+' FNU Z SCALE CY(1) CY(2)
+ NZ IFAIL'
WRITE (NOUT,*)
20 READ (NIN,*,END=40) FNU, Z, SCALE
IFAIL = 0
*
CALL S18DEF(FNU,Z,N,SCALE,CY,NZ,IFAIL)
*
WRITE (NOUT,99998) FNU, Z, SCALE, CY(1), CY(2), NZ, IFAIL
GO TO 20
40 STOP
*
99999 FORMAT (1X,A,I2)
99998 FORMAT (1X,F7.4,' (',F7.3,',',F7.3,') ',A,
+ 2(' (',F7.3,',',F7.3,')'),I4,I4)
END
F02FDF F02GAF F02GBF F02HDFSome details of the results may vary, depending on whether the program is linked to the LAPACK routines in Chapter F08 or to the LAPACK routines in the Digital Extended Math Library (DXML). In particular, if DXML is used, computed eigenvectors and Schur vectors may not be normalised as specified in the NAG documentation; they may differ by a (complex) scalar multiple of absolute value 1. Similar comments apply to the following F08 routines:
F08FFF F08FTF F08GFF F08GTF F08HEF F08HSF F08JEF F08JGF F08JUF F08KTF F08NFF F08NGF F08NHF F08NTF F08NUF F08NVF F08PEF F08PSF F08QGF F08QUFThe example programs for the undocumented routines F06PBF, F06SBF, F06YCF and F06ZCF cannot be linked if using the Shareable Library. This is because a different version of the error handler is used in these tests. This does not affect the efficacy of these routines in normal usage.
S07AAF F(1) = 1.0D+13
F(2) = 1.0D-14
S10AAF E(1) = 18.5
S10ABF E(1) = 709.0
S10ACF E(1) = 709.0
S13AAF x(hi) = 709.0
S13ACF x(hi) = 1.0D+16
S13ADF x(hi) = 1.0D+17
S14AAF IFAIL = 1 if X > 170.0
IFAIL = 2 if X < -170.0
IFAIL = 3 if abs(X) < 2.70D-308
S14ABF IFAIL = 2 if X > 1.28D+305
S15ADF x(hi) = 26.6
x(low) = -6.25
S15AEF x(hi) = 6.25
S17ACF IFAIL = 1 if X > 1.0D+16
S17ADF IFAIL = 1 if X > 1.0D+16
IFAIL = 3 if 0.0 < X <= 2.70D-308
S17AEF IFAIL = 1 if abs(X) > 1.0D+16
S17AFF IFAIL = 1 if abs(X) > 1.0D+16
S17AGF IFAIL = 1 if X > 103.9
IFAIL = 2 if X < -5.6D+10
S17AHF IFAIL = 1 if X > 104.1
IFAIL = 2 if X < -5.6D+10
S17AJF IFAIL = 1 if X > 104.1
IFAIL = 2 if X < -1.8D+9
S17AKF IFAIL = 1 if X > 104.1
IFAIL = 2 if X < -1.8D+9
S17DCF IFAIL = 2 if abs (Z) < 9.81D-306
IFAIL = 4 if abs (Z) or FNU+N-1 > 3.27D+4
IFAIL = 5 if abs (Z) or FNU+N-1 > 1.07D+9
S17DEF IFAIL = 2 if imag (Z) > 702.0
IFAIL = 3 if abs (Z) or FNU+N-1 > 3.27D+4
IFAIL = 4 if abs (Z) or FNU+N-1 > 1.07D+9
S17DGF IFAIL = 3 if abs (Z) > 1.02D+3
IFAIL = 4 if abs (Z) > 1.04D+6
S17DHF IFAIL = 3 if abs (Z) > 1.02D+3
IFAIL = 4 if abs (Z) > 1.04D+6
S17DLF IFAIL = 2 if abs (Z) < 9.81D-306
IFAIL = 4 if abs (Z) or FNU+N-1 > 3.27D+4
IFAIL = 5 if abs (Z) or FNU+N-1 > 1.07D+9
S18ADF IFAIL = 2 if 0.0 < X <= 2.70D-308
S18AEF IFAIL = 1 if abs(X) > 712.3
S18AFF IFAIL = 1 if abs(X) > 712.3
S18CDF IFAIL = 2 if 0.0 < X <= 2.70D-308
S18DCF IFAIL = 2 if abs (Z) < 9.81D-306
IFAIL = 4 if abs (Z) or FNU+N-1 > 3.27D+4
IFAIL = 5 if abs (Z) or FNU+N-1 > 1.07D+9
S18DEF IFAIL = 2 if real (Z) > 702.0
IFAIL = 3 if abs (Z) or FNU+N-1 > 3.27D+4
IFAIL = 4 if abs (Z) or FNU+N-1 > 1.07D+9
S19AAF IFAIL = 1 if abs(x) >= 49.50
S19ABF IFAIL = 1 if abs(x) >= 49.50
S19ACF IFAIL = 1 if X > 998.24
S19ADF IFAIL = 1 if X > 998.24
S21BCF IFAIL = 3 if an argument < 9.944D-206
IFAIL = 4 if an argument >= 5.990D+202
S21BDF IFAIL = 3 if an argument < 2.238D-103
IFAIL = 4 if an argument >= 1.769D+102
X01AAF (PI) = 3.1415926535897932 X01ABF (GAMMA) = 0.5772156649015329
The basic parameters of the model
X02BHF = 2 X02BJF = 53 X02BKF = -1023 X02BLF = 1023 X02DJF = .TRUE.Derived parameters of the floating-point arithmetic
X02AJF = Z'0000000000003CC0' ( 1.11022302462516D-16 ) X02AKF = Z'0000000000000010' ( 5.56268464626804D-309 ) X02ALF = Z'FFFFFFFFFFFF7FFF' ( 8.98846567431158D+307 ) X02AMF = Z'0074000000000020' ( 1.11253692925364D-308 ) X02ANF = Z'9DE7333F504F0033' ( 2.68590174324498D-308 )Parameters of other aspects of the computing environment
X02AHF = Z'0000000000004970' ( 1.42724769270596D+45 ) X02BBF = 2147483647 X02BEF = 15 X02DAF = .FALSE.
A full on-line version of the NAG Fortran Library Manual is available in the form of Portable Document Format (PDF) files. Please contact NAG if you are interested in this.
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