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 HTML form. Item (a) is also supplied in plain text form.
Assuming that libnag.a has been installed in a directory in the search path of the linker, such as /usr/lib, then you may link to the NAG Fortran Library in the following manner:
f77 driver.f -lnagor
f90 driver.f -lnagwhere driver.f is your application program.
Assuming that libnagdx.a has been installed in a directory in the search path of the linker, then if you wish to access the BLAS and/or LAPACK routines supplied in the Digital Extended Math Library (DXML) this can be done in the following manner:
f77 driver.f -lnagdx -ldxmlor
f90 driver.f -lnagdx -ldxml
If either of the shareable versions of the libraries (libnag.so and libnagdx.so) have been created and installed in a directory in the search path of the linker, these will be linked with instead of the static versions.
nagexample c06eafwill copy the example program and its data into the files c06eafe.f and c06eafe.d in the current directory and process them to produce the example program results.
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 (.mod files) and they can be accessed by specifying the -I"pathname" option on each f90 invocation, where "pathname" is the path of the directory containing the .mod files.
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
S07AAF F(1) = 1.0D+13 F(2) = 1.0D-14 S10AAF E(1) = 18.50 S10ABF E(1) = 708.0 S10ACF E(1) = 708.0 S13AAF x(hi) = 708.3 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) < 2.23D-308 S14ABF IFAIL = 2 if X > 2.55D+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 <= 2.23D-308 S17AEF IFAIL = 1 if abs(X) > 1.0D+16 S17AFF IFAIL = 1 if abs(X) > 1.0D+16 S17AGF IFAIL = 1 if X > 103.8 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) < 3.93D-305 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) > 700.0 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) < 3.93D-305 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 <= 2.23D-308 S18AEF IFAIL = 1 if abs(X) > 711.6 S18AFF IFAIL = 1 if abs(X) > 711.6 S18CDF IFAIL = 2 if 0.0 < X <= 2.23D-308 S18DCF IFAIL = 2 if abs (Z) < 3.93D-305 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) > 700.0 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 > 997.26 S19ADF IFAIL = 1 if X > 997.26 S21BCF IFAIL = 3 if an argument < 1.579D-205 IFAIL = 4 if an argument >= 3.774D+202 S21BDF IFAIL = 3 if an argument < 2.820D-103 IFAIL = 4 if an argument >= 1.404D+102
X01AAF (PI) = 3.1415926535897932 X01ABF (GAMMA) = 0.5772156649015329
The basic parameters of the model
X02BHF = 2 X02BJF = 53 X02BKF = -1021 X02BLF = 1024 X02DJF = .TRUE.Derived parameters of the floating-point arithmetic
X02AJF = Z'3CA0000000000001' ( 1.11022302462516D-16 ) X02AKF = Z'0010000000000000' ( 2.22507385850721D-308 ) X02ALF = Z'7FEFFFFFFFFFFFFF' ( 1.79769313486231D+308 ) X02AMF = Z'0010000000000000' ( 2.22507385850721D-308 ) X02ANF = Z'0036A09E667F3BCD' ( 1.25869185119309D-307 )Parameters of other aspects of the computing environment
X02AHF = Z'4950000000000000' ( 1.42724769270596D+45 ) X02BBF = 2147483647 X02BEF = 15 X02DAF = .FALSE.
On-line documentation is bundled with this implementation. Please see the Readme file on the distribution medium for further information.
The NAG Response Centres are available for general enquiries from all users and also for technical queries from sites with an annually licensed product or support service.
The Response Centres are open during office hours, but contact is possible by fax, email and phone (answering machine) at all times.
When contacting a Response Centre please quote your NAG site reference and NAG product code (in this case FLDAU19DA).
The NAG Website is an information service providing items of interest to users and prospective users of NAG products and services. The information is reviewed and updated regularly and includes implementation availability, descriptions of products, downloadable software, product documentation and technical reports. The NAG Website can be accessed at
or
https://www.nag.com/ (in the USA)
NAG Ltd Wilkinson House Jordan Hill Road OXFORD OX2 8DR NAG Ltd Response Centre United Kingdom email: infodesk@nag.co.uk Tel: +44 (0)1865 511245 Tel: +44 (0)1865 311744 Fax: +44 (0)1865 310139 Fax: +44 (0)1865 311755 NAG Inc 1400 Opus Place, Suite 200 Downers Grove IL 60515-5702 NAG Inc Response Center USA email: infodesk@nag.com Tel: +1 630 971 2337 Tel: +1 630 971 2345 Fax: +1 630 971 2706 Fax: +1 630 971 2346 NAG GmbH Schleissheimerstrasse 5 85748 Garching Deutschland email: naggmbh@nag.co.uk Tel: +49 (0)89 320 7395 Fax: +49 (0)89 320 7396 Nihon NAG KK Nagashima Building 2F 2-24-3 Higashi Shibuya-ku Tokyo Japan email: help@nag-j.co.jp Tel: +81 (0)3 5485 2901 Fax: +81 (0)3 5485 2903