In addition, NAG recommends that before calling any library routine you should read the following reference material (see Section 5):
(a) Essential Introduction
(b) Chapter Introduction
(c) Routine Document
The libraries supplied with this implementation have not been compiled in a manner that facilitates the use of multiple threads.
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:
xlf -q64 driver.f -lnagwhere driver.f is your application program.
If the shared object form of the NAG Fortran Library has been installed, then you may link to it with the following command:
xlf -q64 driver.f -lnag_sh
If the IBM Engineering and Scientific Subroutine Library (ESSL) is installed, as well as the BLAS-free version of the NAG Library, nag_use_essl.a, then the driver program may be linked to them in the following manner:
xlf -q64 driver.f -lnag_use_essl -lessl
If you wish to use the xlf90 compiler rather than xlf, the compiler calls follow a similar pattern. For example:
xlf90 -q64 -qfixed driver.f90 -lnagwhere the option -qfixed (if relevant) indicates to the compiler that the Fortran code is in fixed-input format.
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 the distributed example programs are those used in this implementation and may not correspond exactly with the programs published in the manual. The distributed example programs should be used in preference wherever possible.
The examples results provided are those obtained using libnag.a. Using libnag_sh.a, or libnag_use_essl.a and ESSL, may produce slightly different results.
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
(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, their use is recommended in preference to 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
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 = 1.11022302462516D-16 X02AKF = 2.22507385850721D-308 X02ALF = 1.79769313486231D+308 X02AMF = 2.22507385850721D-308 X02ANF = 2.22507385850721D-308Parameters of other aspects of the computing environment
X02AHF = 8.11296384146067D+31 X02BBF = 2147483647 X02BEF = 15 X02DAF = .FALSE.
A full on-line version of the NAG Fortran Library Manual is supplied in the form of Portable Document Format (PDF) files, with an HTML index, in the NAGdoc directory. The introductory material is also provided as HTML files in the NAGdoc directory.
A main index file has been provided (NAGdoc/fl/html/mark20.html) which contains a fully linked contents document pointing to all the available PDF (and where available HTML) files. Use your HTML browser to navigate from here.
In addition the following are provided in the doc directory:
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