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 -lnag -lcomplib.sgimath
where driver.f is your application program. This will make use of the BLAS and LAPACK routines supplied by Silicon Graphics in the complib.sgimath library (assumed to have been installed in /usr/lib), although the NAG BLAS and LAPACK routines may be accessed by their NAG names.
If you wish to access the NAG BLAS and/or LAPACK routines by the standard BLAS/LAPACK names, then the driver program should be linked with libnagblas.a, e.g.
f77 driver.f -lnagblas
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.
F02FDF F02HDFSome details of the results may therefore vary, according to whether the program is linked to the LAPACK routines in Chapter F08 or to the Silicon Graphics versions in the complib.sgimath library. In particular, if the complib.sgimath library is used, computed eigenvectors and Schur vectors may not be normalised as described 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 F08NFF F08NGF F08NHF F08NTF F08NUF F08NVF F08PEF F08PSF F08QGF F08QUF
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) = 1.8D+16 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'0010000000000000' ( 2.22507385850721D-308 )Parameters of other aspects of the computing environment
X02AHF = Z'4350000000000000' ( 1.80143985094819D+16 ) 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.
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