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 been compiled in a manner that facilitates the use of multiple threads.
This implementation supports the XL Fortran compile-time option -qextname.
http://www.nag.co.uk/doc/inun/fl22/il6dal/postrelease.html
for details of any new information related to the applicability or usage of this implementation.
In this section we assume that the library has been installed in the directory [INSTALL_DIR].
By default [INSTALL_DIR] (see Installer's Note (in.html)) is /opt/NAG/flil622dal or /usr/local/NAG/flil622dal depending on your system; however it could have been changed by the person who did the installation. To identify [INSTALL_DIR] for this installation:
xlf_r -q64 -qnosave driver.f [INSTALL_DIR]/lib/libnag_essl.a -lesslwhere driver.f is your application program;
or
xlf_r -q64 -qnosave driver.f -L[INSTALL_DIR]/lib/ -lnag_essl -lesslif the shareable library is required. Please note the shareable library is fully resolved so that, as long as the environment variable LD_LIBRARY_PATH is set correctly at link time (see below), you need not link against other run-time libraries explicitly.
However, if you prefer to link to a version of the NAG Library which does not require the use of ESSL you may wish to use the self-contained libraries as follows:
xlf_r -q64 -qnosave driver.f [INSTALL_DIR]/lib/libnag_nag.aor
xlf_r -q64 -qnosave driver.f -L[INSTALL_DIR]/lib/ -lnag_nagif the shareable library is required.
If the compiled libraries and the supplied ESSL libraries are pointed at by symbolic links from a directory in the search path of the linker, such as /usr/lib, then you may alternatively link in the following manner:
xlf_r -q64 -qnosave driver.f -lnag_essl -lesslThis will usually link to the shareable library in preference to the static library if both the libraries are at the same location. Please note the shareable library is fully resolved so that, as long as the environment variable LD_LIBRARY_PATH is set correctly at link time (see below), you need not link against other run-time libraries explicitly.
To use the static library libnag_essl.a you need the -Wl,-static compiler flag to switch static binding on and -Wl,-Bdynamic to switch dynamic binding on:
xlf_r -q64 -qnosave driver.f -Wl,-static -lnag_essl -Wl,-Bdynamic -lessl
Similarly for the self-contained libraries the commands
xlf_r -q64 -qnosave driver.f -lnag_nagmay be used to link to the shared library or
xlf_r -q64 -qnosave driver.f -Wl,-static -lnag_nag -Wl,-Bdynamicmay be used to link to the static NAG library.
If your application has been linked with the shareable NAG library then the environment variable LD_LIBRARY_PATH must be set (or extended) to allow run time linkage.
In the C shell type:
setenv LD_LIBRARY_PATH [INSTALL_DIR]/libto set LD_LIBRARY_PATH, or
setenv LD_LIBRARY_PATH [INSTALL_DIR]/lib:${LD_LIBRARY_PATH}to extend LD_LIBRARY_PATH if you already have it set.
In the Bourne shell, type:
LD_LIBRARY_PATH=[INSTALL_DIR]/lib export LD_LIBRARY_PATHto set LD_LIBRARY_PATH, or
LD_LIBRARY_PATH=[INSTALL_DIR]/lib:${LD_LIBRARY_PATH} export LD_LIBRARY_PATHto extend LD_LIBRARY_PATH if you already have it set.
Note that you may also need to set LD_LIBRARY_PATH to point at other things such as compiler run-time libraries, for example if you are using a newer version of the compiler.
(a) subroutines are called as such;
(b) functions are declared with the right type;
(c) the correct number of arguments are passed; and
(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 -Ipathname option on each compiler invocation, where pathname is the path of the directory containing the compiled interface blocks, and should be one of:
[INSTALL_DIR]/nag_interface_blocks/ext to access interface blocks compiled with the -qextname option
or
[INSTALL_DIR]/nag_interface_blocks/noext to access interface blocks compiled without the -qextname option
In order to make use of these modules from existing Fortran 77 code, the following changes need to be made:
The above steps need to be done for each unit (main program, function or subroutine) in your code.
These changes are illustrated by showing the conversion of the Fortran 77 version of the example program for NAG Fortran Library routine D01DAF. 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.
* D01DAF Example Program Text * Mark 14 Revised. NAG Copyright 1989. ***************************************************** * Add USE statements for relevant chapters * USE NAG_F77_D_CHAPTER, ONLY: D01DAF * * ***************************************************** * .. Parameters .. INTEGER NOUT PARAMETER (NOUT=6) * .. Local Scalars .. DOUBLE PRECISION ABSACC, ANS, YA, YB INTEGER IFAIL, NPTS * .. External Functions .. DOUBLE PRECISION FA, FB, PHI1, PHI2A, PHI2B EXTERNAL FA, FB, PHI1, PHI2A, PHI2B * .. External Subroutines .. ****************************************************** * EXTERNAL declarations need to be removed. * * EXTERNAL D01DAF * * ****************************************************** * .. Executable Statements .. WRITE (NOUT,*) 'D01DAF Example Program Results' YA = 0.0D0 YB = 1.0D0 ABSACC = 1.0D-6 WRITE (NOUT,*) IFAIL = 1 * CALL D01DAF(YA,YB,PHI1,PHI2A,FA,ABSACC,ANS,NPTS,IFAIL) * IF (IFAIL.LT.0) THEN WRITE (NOUT,99998) ' ** D01DAF returned with IFAIL = ', IFAIL ELSE * WRITE (NOUT,*) 'First formulation' WRITE (NOUT,99999) 'Integral =', ANS WRITE (NOUT,99998) 'Number of function evaluations =', NPTS IF (IFAIL.GT.0) WRITE (NOUT,99998) 'IFAIL = ', IFAIL WRITE (NOUT,*) WRITE (NOUT,*) 'Second formulation' IFAIL = 1 * CALL D01DAF(YA,YB,PHI1,PHI2B,FB,ABSACC,ANS,NPTS,IFAIL) * WRITE (NOUT,99999) 'Integral =', ANS WRITE (NOUT,99998) 'Number of function evaluations =', NPTS IF (IFAIL.GT.0) WRITE (NOUT,99998) 'IFAIL = ', IFAIL END IF * 99999 FORMAT (1X,A,F9.4) 99998 FORMAT (1X,A,I5) END * DOUBLE PRECISION FUNCTION PHI1(Y) * .. Scalar Arguments .. DOUBLE PRECISION Y * .. Executable Statements .. PHI1 = 0.0D0 RETURN END * DOUBLE PRECISION FUNCTION PHI2A(Y) * .. Scalar Arguments .. DOUBLE PRECISION Y * .. Intrinsic Functions .. INTRINSIC SQRT * .. Executable Statements .. PHI2A = SQRT(1.0D0-Y*Y) RETURN END * DOUBLE PRECISION FUNCTION FA(X,Y) * .. Scalar Arguments .. DOUBLE PRECISION X, Y * .. Executable Statements .. FA = X + Y RETURN END * DOUBLE PRECISION FUNCTION PHI2B(Y) ***************************************************** * Add USE statements for relevant chapters * USE NAG_F77_X_CHAPTER, ONLY: X01AAF * * ***************************************************** * .. Scalar Arguments .. DOUBLE PRECISION Y * .. External Functions .. ****************************************************** * Function Type declarations need to be removed. * * DOUBLE PRECISION X01AAF * * ****************************************************** ****************************************************** * EXTERNAL declarations need to be removed. * * EXTERNAL X01AAF * * ****************************************************** * .. Executable Statements .. PHI2B = 0.5D0*X01AAF(0.0D0) RETURN END * DOUBLE PRECISION FUNCTION FB(X,Y) * .. Scalar Arguments .. DOUBLE PRECISION X, Y * .. Intrinsic Functions .. INTRINSIC COS, SIN * .. Executable Statements .. FB = Y*Y*(COS(X)+SIN(X)) RETURN END
Note that the example material has been adapted, if necessary, from that published in the Library Manual, so that programs are suitable for execution with this implementation with no further changes. The distributed example programs should be used in preference to the versions in the Library Manual wherever possible.
The directory [INSTALL_DIR]/scripts contains eight scripts nag_example_essl, nag_example_shar_essl, nag_example_essl_ext, nag_example_shar_essl_ext, nag_example, nag_example_shar, nag_example_ext and nag_example_shar_ext.
The example programs are most easily accessed by one of the commands
The scripts nag_example*_ext are the versions of those scripts which use the -qextname XL Fortran Compiler option.
Each command will provide you with a copy of an example program (and its data, if any), compile the program and link it with the appropriate libraries (showing you the compile command so that you can recompile your own version of the program). Finally, the executable program will be run, presenting its output to stdout, which is redirected to a file.
The example program concerned is specified by the argument to the command, e.g.
nag_example_essl e04ucfwill copy the example program and its data into the files e04ucfe.f and e04ucfe.d in the current directory and process them to produce the example program results in the file e04ucfe.r.
The distributed example results are those obtained with the static library libnag_essl.a, (using the ESSL BLAS and LAPACK routines). Running the examples with the self-contained library (using the NAG BLAS and LAPACK routines) may give slightly different results.
In order to support all implementations of the Library, the Manual has adopted a convention of using bold italics to distinguish terms which have different interpretations in different implementations.
For this double precision implementation, the bold italicised terms used in the Library Manual should be interpreted as follows:
real means REAL double precision means DOUBLE PRECISION complex means COMPLEX complex*16 means COMPLEX*16 (or equivalent) basic precision means DOUBLE PRECISION additional precision means quadruple precision reduced precision means REAL
Another important bold italicised term is machine
precision, which denotes the relative precision to which
double precision floating-point numbers are stored in
the computer, e.g. in an implementation with approximately 16 decimal
digits of precision, machine precision has a value of
approximately
The precise value of machine precision is given by the routine X02AJF. Other routines in Chapter X02 return the values of other implementation-dependent constants, such as the overflow threshold, or the largest representable integer. Refer to the X02 Chapter Introduction for more details.
The bold italicised term block size is used only in Chapters F07 and F08. It denotes the block size used by block algorithms in these chapters. You only need to be aware of its value when it affects the amount of workspace to be supplied – see the parameters WORK and LWORK of the relevant routine documents and the Chapter Introduction.
In Chapters F06, F07 and F08, alternate routine names are available for BLAS and LAPACK derived routines. For details of the alternate routine names please refer to the relevant Chapter Introduction. Note that applications should reference routines by their BLAS/LAPACK names, rather than their NAG-style names, for optimum performance.
In this implementation calls to the NAG version of the following Basic Linear Algebra Subprograms (BLAS) and linear algebra routines (LAPACK) are included in the libraries libnag_essl.a and libnag_essl.so to avoid problems with the vendor version:
DGELS DGMEV DGEQRF DGETRF DPOTRF DPPSV DPPTRF DSGESV ZCGESV ZGEQRF ZGETRF ZGELS ZPOTRF
S07AAF F_1 = 1.0E+13 F_2 = 1.0E-14 S10AAF E_1 = 1.8715E+1 S10ABF E_1 = 7.080E+2 S10ACF E_1 = 7.080E+2 S13AAF X_hi = 7.083E+2 S13ACF X_hi = 1.0E+16 S13ADF X_hi = 1.0E+17 S14AAF IFAIL = 1 if X > 1.70E+2 IFAIL = 2 if X < -1.70E+2 IFAIL = 3 if abs(X) < 2.23E-308 S14ABF IFAIL = 2 if X > X_big = 2.55E+305 S15ADF X_hi = 2.65E+1 S15AEF X_hi = 2.65E+1 S15AFF underflow trap was necessary S15AGF IFAIL = 1 if X >= 2.53E+307 IFAIL = 2 if 4.74E+7 <= X < 2.53E+307 IFAIL = 3 if X < -2.66E+1 S17ACF IFAIL = 1 if X > 1.0E+16 S17ADF IFAIL = 1 if X > 1.0E+16 IFAIL = 3 if 0.0E0 < X <= 2.23E-308 S17AEF IFAIL = 1 if abs(X) > 1.0E+16 S17AFF IFAIL = 1 if abs(X) > 1.0E+16 S17AGF IFAIL = 1 if X > 1.038E+2 IFAIL = 2 if X < -5.7E+10 S17AHF IFAIL = 1 if X > 1.041E+2 IFAIL = 2 if X < -5.7E+10 S17AJF IFAIL = 1 if X > 1.041E+2 IFAIL = 2 if X < -1.9E+9 S17AKF IFAIL = 1 if X > 1.041E+2 IFAIL = 2 if X < -1.9E+9 S17DCF IFAIL = 2 if abs(Z) < 3.92223E-305 IFAIL = 4 if abs(Z) or FNU+N-1 > 3.27679E+4 IFAIL = 5 if abs(Z) or FNU+N-1 > 1.07374E+9 S17DEF IFAIL = 2 if imag(Z) > 7.00921E+2 IFAIL = 3 if abs(Z) or FNU+N-1 > 3.27679E+4 IFAIL = 4 if abs(Z) or FNU+N-1 > 1.07374E+9 S17DGF IFAIL = 3 if abs(Z) > 1.02399E+3 IFAIL = 4 if abs(Z) > 1.04857E+6 S17DHF IFAIL = 3 if abs(Z) > 1.02399E+3 IFAIL = 4 if abs(Z) > 1.04857E+6 S17DLF IFAIL = 2 if abs(Z) < 3.92223E-305 IFAIL = 4 if abs(Z) or FNU+N-1 > 3.27679E+4 IFAIL = 5 if abs(Z) or FNU+N-1 > 1.07374E+9 S18ADF IFAIL = 2 if 0.0E0 < X <= 2.23E-308 S18AEF IFAIL = 1 if abs(X) > 7.116E+2 S18AFF IFAIL = 1 if abs(X) > 7.116E+2 S18DCF IFAIL = 2 if abs(Z) < 3.92223E-305 IFAIL = 4 if abs(Z) or FNU+N-1 > 3.27679E+4 IFAIL = 5 if abs(Z) or FNU+N-1 > 1.07374E+9 S18DEF IFAIL = 2 if real(Z) > 7.00921E+2 IFAIL = 3 if abs(Z) or FNU+N-1 > 3.27679E+4 IFAIL = 4 if abs(Z) or FNU+N-1 > 1.07374E+9 S19AAF IFAIL = 1 if abs(X) >= 5.04818E+1 S19ABF IFAIL = 1 if abs(X) >= 5.04818E+1 S19ACF IFAIL = 1 if X > 9.9726E+2 S19ADF IFAIL = 1 if X > 9.9726E+2 S21BCF IFAIL = 3 if an argument < 1.583E-205 IFAIL = 4 if an argument >= 3.765E+202 S21BDF IFAIL = 3 if an argument < 2.813E-103 IFAIL = 4 if an argument >= 1.407E+102
X01AAF (pi) = 3.1415926535897932 X01ABF (gamma) = 0.5772156649015328
X02BHF = 2 X02BJF = 53 X02BKF = -1021 X02BLF = 1024 X02DJF = .TRUE.Derived parameters of the floating-point arithmetic
X02AJF = 1.11022302462516E-16 X02AKF = 2.22507385850721E-308 X02ALF = 1.79769313486231E+308 X02AMF = 2.22507385850721E-308 X02ANF = 2.22507385850721E-308Parameters of other aspects of the computing environment
X02AHF = 1.42724769270596E+45 X02BBF = 2147483647 X02BEF = 15 X02DAF = .TRUE.
The Library Manual is available as part of the installation or via download from the NAG website. The most up-to-date version of the documentation is accessible via the NAG website at http://www.nag.co.uk/numeric/FL/FLdocumentation.asp.
The Library Manual is supplied in the following formats:
The following main index files have been provided for these formats:
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Advice on viewing and navigating the formats available can be found in the Online Documentation document.
In addition the following are provided:
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