FLDLL204ZL Users' Note

NAG Fortran Library, Mark 20

FLDLL204ZL - License Managed

Windows 95/98/NT/ME/2000/XP Compaq Visual Fortran

Users' Note

1. Introduction
2. Availability of Routines
3. Restrictions
4. General Information
5. Routine-specific Information
6. Documentation
7. Support from NAG
8. User Feedback
Appendix - Contact Addresses

1. Introduction

All users of the NAG Fortran Library should make sure they read the Users' Note that is appropriate for the implementation they are using. These documents provide implementation-specific details that supplement the information provided in the NAG Fortran Library Manual and Introductory Guide. Wherever those manuals refer to the "Users' Note for your implementation", you should consult this note.

In addition NAG recommends before calling any library routine you should read the following reference material:

(a) Essential Introduction
(b) Chapter Introduction
(c) Routine Document

2. Availability of Routines

All routines listed in the chapter contents of the NAG Fortran Library, Mark 20, are available in this implementation. At Mark 20, 95 new primary ("user-callable") and 36 new thread safe routines have been introduced, and 2 routines deleted. Please consult the 'News' document in the online documentation for lists of these routines and for a list of routines scheduled for withdrawal at Mark 21 or later. Your suggestions for new algorithms for future releases of the Library are welcomed (see Section 8).

3. Restrictions

The default Compaq Visual Fortran calling convention is used. In essence this means that parameters are accessed by reference. Character strings are passed by reference followed immediately by the value of the length of the string.

Fortran 90 users are advised that the compiled *.mod files (the interface blocks) have been compiled with Compaq Visual Fortran 6.1. These are not compatible with earlier Digital Fortran compiler conventions and so users will have to compile the interface blocks themselves if the earlier compiler is to be used.

When the DLLs are used with a non-CVF compiler, please note that two input/out systems are in use: those of CVF for library routines and of course the compiler's own input/output routines for the calling program. This means that programs like E04UDF example program cannot read the data from just one file. This is because the program reads some of the data using its input/output system. When the option setting routine tries to read the data file, the CVF input/out routines are used. The two input/output systems are completely disjoint and so in particular CVF has no knowledge of the position in the data file that the program input/output system has reached. The problem is circumvented by having two separate data files. Routines affected by this are mainly the option setting routines in chapters H02 and E04.

4. General Information

4.1. Calling the DLLs from Compaq Visual Fortran

Assuming that the directory containing the libraries has been added to the LIB environment variable, you may compile and link to the NAG Fortran Library on the command line in the following manner:

df driver.for dll20dds.lib dll20dd.lib

where driver.for is your application program.

If you are using Developer Studio, after establishing a workspace you should make the system aware of the libraries by clicking on Project, then Settings, then Link and entering the library under Object/library modules. The installation procedure attempts to make Developer Studio aware of the location of the NAG libraries supplied by NAG. You can confirm that it has been successful by examining the Directories pane when Tools/Options/Directories/Show directories for/Libraries has been selected. If the installation had difficulty, perhaps because several versions of Developer Studio were recorded in the registry, then you can set this facility manually in the Directories pane. Otherwise you will have to specify the full path name of the libraries in Object/library modules.

4.2. Calling the DLLs from Absoft Pro Fortran

There are three issues to consider when using the NAG library with Absoft Pro Fortran:

All real arguments and functions are DOUBLE PRECISION.
All library and call back procedures must be declared STDCALL (see lines marked "CHANGE1" in the following code").
CHARACTER arguments to the NAG library procedures must be passed using the CVF protocol. This protocol passes the length of the CHARACTER argument as an integer value immediately after the CHARACTER argument itself. The Absoft Pro Fortran compilers pass CHARACTER arguments as integer values after the formal argument list.

To force the protocol, use the sequence VAL(LOC(...)). The LOC(...) function takes the address of its argument. The VAL(...) function passes its argument by value. Then use VAL(...) immediately after this sequence to pass the length of the argument.

In the following code the formal argument RELABBS (actual argument 'Default') in all the calls to the routine D02CJF in the example program D02CJFE.F is replaced by two arguments:
```
VAL(LOC(RELABS)), VAL(7)
```
(see lines marked "CHANGE2"), where RELABS is declared and assigned the value 'Default' in the lines marked "NEW")

For example, the following code is a modified version of the example program D02CJFE.F provided by NAG. The lines marked "NEW", "CHANGE1" and "CHANGE2" contain the changes you need to make to the code supplied:

*     D02CJF Example Program Text
*     Mark 14 Revised.  NAG Copyright 1989.
*     .. Parameters ..
      CHARACTER        RELABS*15                                        !NEW
      INTEGER          NOUT
      PARAMETER        (NOUT=6)
      INTEGER          N, IW
      PARAMETER        (N=3,IW=21*N+28)
*     .. Scalars in Common ..
      DOUBLE PRECISION H, XEND
      INTEGER          K
*     .. Local Scalars ..
      DOUBLE PRECISION PI, TOL, X
      INTEGER          I, IFAIL, J
*     .. Local Arrays ..
      DOUBLE PRECISION W(IW), Y(N)
*     .. External Functions ..
      DOUBLE PRECISION D02CJW, G, X01AAF
      STDCALL EXTERNAL D02CJW, G, X01AAF                                !CHANGE1
*     .. External Subroutines ..
      STDCALL EXTERNAL D02CJF, D02CJX, FCN, OUT                         !CHANGE1
*     .. Intrinsic Functions ..
      INTRINSIC        DBLE
*     .. Common blocks ..
      COMMON           XEND, H, K
*     .. Executable Statements ..
      WRITE (NOUT,*) 'D02CJF Example Program Results'
      RELABS = "Default"                                                !NEW
      XEND = 10.0D0
      PI = X01AAF(0.0D0)
      WRITE (NOUT,*)
      WRITE (NOUT,*) 'Case 1: intermediate output, root-finding'
      DO 20 J = 4, 5
         TOL = 10.0D0**(-J)
         WRITE (NOUT,*)
         WRITE (NOUT,99999) ' Calculation with TOL =', TOL
         X = 0.0D0
         Y(1) = 0.5D0
         Y(2) = 0.5D0
         Y(3) = PI/5.0D0
         K = 4
         H = (XEND-X)/DBLE(K+1)
         WRITE (NOUT,*) '     X         Y(1)         Y(2)         Y(3)'
         IFAIL = 0
*
         CALL D02CJF(X,XEND,N,Y,FCN,TOL,VAL(LOC(RELABS)),VAL(7),OUT,G,W,!CHANGE2
     +               IFAIL)
*
         WRITE (NOUT,99998) '  Root of Y(1) = 0.0 at', X
         WRITE (NOUT,99997) '  Solution is', (Y(I),I=1,N)
   20 CONTINUE
      WRITE (NOUT,*)
      WRITE (NOUT,*)
      WRITE (NOUT,*) 'Case 2: no intermediate output, root-finding'
      DO 40 J = 4, 5
         TOL = 10.0D0**(-J)
         WRITE (NOUT,*)
         WRITE (NOUT,99999) ' Calculation with TOL =', TOL
         X = 0.0D0
         Y(1) = 0.5D0
         Y(2) = 0.5D0
         Y(3) = PI/5.0D0
         IFAIL = 0
*
         CALL D02CJF(X,XEND,N,Y,FCN,TOL,VAL(LOC(RELABS)),VAL(7),D02CJX, !CHANGE2
     +               G,W,IFAIL)
*
         WRITE (NOUT,99998) '  Root of Y(1) = 0.0 at', X
         WRITE (NOUT,99997) '  Solution is', (Y(I),I=1,N)
   40 CONTINUE
      WRITE (NOUT,*)
      WRITE (NOUT,*)
      WRITE (NOUT,*) 'Case 3: intermediate output, no root-finding'
      DO 60 J = 4, 5
         TOL = 10.0D0**(-J)
         WRITE (NOUT,*)
         WRITE (NOUT,99999) ' Calculation with TOL =', TOL
         X = 0.0D0
         Y(1) = 0.5D0
         Y(2) = 0.5D0
         Y(3) = PI/5.0D0
         K = 4
         H = (XEND-X)/DBLE(K+1)
         WRITE (NOUT,*) '     X         Y(1)         Y(2)         Y(3)'
         IFAIL = 0
*
         CALL D02CJF(X,XEND,N,Y,FCN,TOL,VAL(LOC(RELABS)),VAL(7),OUT,    !CHANGE2
     +               D02CJW,W,IFAIL)
*
   60 CONTINUE
      WRITE (NOUT,*)
      WRITE (NOUT,*)
      WRITE (NOUT,*)
     +'Case 4: no intermediate output, no root-finding ( integrate to XE
     +ND)'
      DO 80 J = 4, 5
         TOL = 10.0D0**(-J)
         WRITE (NOUT,*)
         WRITE (NOUT,99999) ' Calculation with TOL =', TOL
         X = 0.0D0
         Y(1) = 0.5D0
         Y(2) = 0.5D0
         Y(3) = PI/5.0D0
         WRITE (NOUT,*) '     X         Y(1)         Y(2)         Y(3)'
         WRITE (NOUT,99996) X, (Y(I),I=1,N)
         IFAIL = 0
*
         CALL D02CJF(X,XEND,N,Y,FCN,TOL,VAL(LOC(RELABS)),VAL(7),D02CJX, !CHANGE
     +               D02CJW,W,IFAIL)
*
         WRITE (NOUT,99996) X, (Y(I),I=1,N)
   80 CONTINUE
      STOP
*
99999 FORMAT (1X,A,D8.1)
99998 FORMAT (1X,A,F7.3)
99997 FORMAT (1X,A,3F13.5)
99996 FORMAT (1X,F8.2,3F13.5)
      END
*
      STDCALL SUBROUTINE OUT(X,Y)                                       !CHANGE1
*     .. Parameters ..
      INTEGER        NOUT
      PARAMETER      (NOUT=6)
      INTEGER        N
      PARAMETER      (N=3)
*     .. Scalar Arguments ..
      DOUBLE PRECISION X
*     .. Array Arguments ..
      DOUBLE PRECISION Y(N)
*     .. Scalars in Common ..
      DOUBLE PRECISION H, XEND
      INTEGER        I
*     .. Local Scalars ..
      INTEGER        J
*     .. Intrinsic Functions ..
      INTRINSIC      DBLE
*     .. Common blocks ..
      COMMON         XEND, H, I
*     .. Executable Statements ..
      WRITE (NOUT,99999) X, (Y(J),J=1,N)
      X = XEND - DBLE(I)*H
      I = I - 1
      RETURN
*
99999 FORMAT (1X,F8.2,3F13.5)
      END
*
      STDCALL SUBROUTINE FCN(T,Y,F)                                     !CHANGE1
*     .. Parameters ..
      INTEGER        N
      PARAMETER      (N=3)
*     .. Scalar Arguments ..
      DOUBLE PRECISION T
*     .. Array Arguments ..
      DOUBLE PRECISION F(N), Y(N)
*     .. Intrinsic Functions ..
      INTRINSIC      COS, TAN
*     .. Executable Statements ..
      F(1) = TAN(Y(3))
      F(2) = -0.032D0*TAN(Y(3))/Y(2) - 0.02D0*Y(2)/COS(Y(3))
      F(3) = -0.032D0/Y(2)**2
      RETURN
      END
*
      STDCALL DOUBLE PRECISION FUNCTION G(T,Y)                          !CHANGE1
*     .. Parameters ..
      INTEGER                     N
      PARAMETER                   (N=3)
*     .. Scalar Arguments ..
      DOUBLE PRECISION            T
*     .. Array Arguments ..
      DOUBLE PRECISION            Y(N)
*     .. Executable Statements ..
      G = Y(1)
      RETURN
      END

Assuming that the directory containing the libraries has been added to the LIB environment variable, you may compile and link to the NAG Fortran Library on the command line in the following manner:

f77 driver.for dll20dds.lib dll20dd.lib

where driver.for is your application program. Calling the DLLs from g77 Fortran

4.3. Calling the DLLs from g77 Fortran

The command for calling the Mark 20 DLLs from g77 is:

g77 -fno-underscoring -fcase-upper -mrtd driver.for dll20dd.lib dll20dds.lib

Character strings arguments demand special attention. Immediately after the character string argument, pass by value the length of the string. For example :

DEV = G01FAF(TAIL,%VAL(1),P,IFAIL)

In the example program D02CJFE.F, you need to replace the formal argument RELABS (actual argument 'Default') in all the calls to the routine D02CJF by:

'Default',%VAL(7)

If the argument is a character array, pass the length of each array element. This information is valid for Cygwin 2.95.2 and later and for Mingw 2.95.3-6 and later.

4.4 Calling the DLLs from Intel Fortran

Assuming that the directory containing the libraries has been added to the LIB environment variable, the DLLs may be used from the Intel Fortran compiler provided the /Gm switch is used. This enables the CVF and Powerstation calling convention. A typical call might be:

ifl /Gm driver.for /link dll20dd.lib dll20dds.lib

where driver.for is your application program.

4.5. Calling the DLLs from Salford Ftn95

You will need Slink version 1.26 or higher and Ftn95 version 1.23 or higher.

Compilation

No source file changes are necessary to call the DLLs from Ftn95. However, since Ftn95 uses a variant of the cdecl calling convention, the compiler has to be told that the routines in the DLLs are to be called using the DVF calling convention. This can be accomplished using the /IMPORT_LIB command line switch as follows:

ftn95 myprog /import_lib install_dir\dll20dds.dll /import_lib install_dir\dll20dd.dll

where install_dir is the location of the DLLs. The full pathname of install_dir should be specified to the DLLs and should be enclosed within quotes if it contains spaces. The effect of this is to assume that all exported names in the DLL are DVF STDCALL and that any use of them should use the CVF STDCALL calling convention. External names passed via the argument list to a routine in a NAG DLL are automatically adjusted for whether or not they occur in the same source

Linking

The NAG libraries may be added to the Slink command line as usual e.g

Slink myprog.obj install_dir\dll20dds.dll install_dir\dll20dd.dll

As with compilation, the full path to the DLLs should be specified here, within quotes if the pathname contains spaces. It is worth emphasising that the linker should link directly against the DLLs not the *.lib files.

4.6. Calling the DLLs from Microsoft C++ 6.0 and Above

Microsoft C++ version 5 and below are not compatible with the DLLs. If this is a problem either update the Microsoft C++ compiler or consider using the static library implementation of NAG, FLW3220DD. If you have version Microsoft 6.0 or above then, with care, the NAG Fortran DLLs may be used from within a C or C++ environment. To assist the user make the mapping between Fortran and C types, a set of C header files and a set of C++ header files are provided. It is recommended that users wishing to use a Fortran DLL routine either copy and paste the relevant section of the appropriate file into their C or C++ applications or simply include the relevant header file with their application.

Examples of the use of the DLLs from C and C++ are given in the ./samples/c_examples directory.

A document, techdoc.html, giving more detailed advice on calling the DLLs from C is available in installation_dir\headers, where installation_dir denotes the directory containing the library files.

Key information:

Specify STDCALL calling convention
Note the different array accessing convention; C is by rows, FORTRAN by columns.
Use the header files provided
Fortran character strings, are treated as two parameters, the string itself and the length of the string.
The .\samples\c_examples directory contains examples which illustrate the use of the DLLs from C.
C programs should have the .c extension; c++ programs an extension .cpp

Assuming that the directory containing the libraries has been added to the LIB environment variable, you may compile and link your C application program to the NAG Fortran Library on the command line in the following manner:

cl driver.c dll20dds.lib dll20dd.lib

where driver.c is your application program. This assumes that the directory containing the header files has been added to the INCLUDE environment variable. If not, you could use:

cl driver.c dll20dds.lib dll20dd.lib /I installation_dir\headers

Here installation_dir denotes the directory containing the library files.

4.7. Calling the DLLs from Absoft C

The header files and discussion in 4.6 Calling the DLLs from Microsoft C apply equally to Absoft C. Currently the only way to use this compiler is to copy the file .\headers\nagmk20.h to the compiler sub-directory Cinclude to allow the compiler access the header file.

Assuming that the directory containing the libraries has been added to the LIB environment variable, you may compile and link your C application program to the NAG Fortran Library on the command line in the following manner:

acc driver.c dll20dds.lib dll20dd.lib

where driver.c is your application program.

4.8. Calling the DLLs from Borland C++

Some selected tests have been made, calling the DLLs from Borland C++, Version 5.0. From these it is concluded that the DLLs may be used in conjunction with the Borland C++ compiler. The discussion in 4.6. Calling the DLLs from Microsoft C applies equally to Borland. Borland import libraries are not supplied but may easily be constructed from the DLLs as follows:

impdef name.def name.dll
implib name.lib name.def

where name denotes the name of the NAG DLL e.g. dll20dds or dll20dd. The first statement constructs a module definitions file, name.def, and the second takes this module definition file and constructs an import library, name.lib. Do not be alarmed by warning messages from IMPDEF. These arise from the number of alternative symbols exported from the DLL in order to provide convenient alternatives for different users.

Assuming that the directory containing the imported libraries has been added to the LIB environment variable, you may compile and link your C application program to the NAG Fortran Library on the command line in the following manner:

bcc32 -Iinstallation_dir\headers driver.c dll20dds.lib dll20dd.lib

where driver.c is your application program and where installation_dir denotes the directory containing the library files.

Alternatively you may add the location of the NAG header files to the configuration file bcc32.cfg. For more details please see the compiler documentation. If you have amended the configuration file then you may simply type:

bcc32 -driver.c dll20dds.lib dll20dd.lib

4.9. Calling the DLLs from Microsoft Visual Basic for Applications

The Fortran DLLs are ideally suited for use within an Excel spreadsheet.

Examples of use of the use of the DLLs from within Excel is given in the .\samples\excel_examples directory. The directory .\samples\excel_examples\linear_algebra contains the file xls_demo.txt. This file gives some hints about using NAG DLLs from within Excel spreadsheets.

Key information:

Use the Declare statements provided in the .\vb_headers\vb directory, by copying from the file and pasting into the module.
Fortran arrays start from 1, so we recommend the ‘Option Base 1’, setting.
Do not use Variant types as actual arguments; Long, Double and Character are required. Use ‘Option Explicit’
Actual arguments for Fortran array variables should be the first element of a VBA array e.g. A(1,1)
Expressions may only be passed to ByVal arguments; other arguments are ByRef by default.
Fortran character arguments are satisfied by two actual arguments: a ByVal string argument and a ByVal length_of_string argument.
Do not allow any output to the screen from a routine in the DLL i.e. set IFAIL = 1 before calling a routine and set all options to produce NO output.

4.10. Calling the DLLs from Microsoft Visual Basic

Visual Basic and VBA have many similarities, so much the VBA specific information above applies directly to Visual Basic. Note especially the remarks about array conventions and string handling.

Examples of use of the DLLs from Visual Basic is given in the .\samples\vb_examples directory.

Key information:

Use the Declare statements provided in the .\vb_headers\vb directory, by copying from the file and pasting into the module.
Fortran arrays start from 1, so we recommend the ‘Option Base 1’, setting.
Do not use Variant types as actual arguments; Long, Double and Character are required. Use ‘Option Explicit’
Actual arguments for Fortran array variables should be the first element of a VBA array e.g. A(1,1)
Expressions may only be passed to ByVal arguments; other arguments are ByRef by default.
Fortran character arguments are satisfied by two actual arguments: a ByVal string argument and a ByVal length_of_string argument.
Do not allow any output to the screen from a routine in the DLL i.e. set IFAIL = 1 before calling a routine and set all options to produce NO output.

4.11. Calling the DLLs from Microsoft VB.NET

Many of the library routines are callable from VB.NET.

Key information:

Use the Declare statements provided in the .\vb_headers\vb.net directory by copying from the file and pasting into the module.
Fortran arrays start at 1, VB.NET arrays start at 0. Be careful to make the correct storage association, passing e.g. A(0,0) as the first element of the VB array A into the Fortran DLL.
The type mappings are now different. Integer corresponds to Fortran's INTEGER type, Double to Fortran's DOUBLE PRECISION
Fortran calls by reference, VB.NET by value. Note the very different Declare statements between VB and VB.NET
VB.NET arrays are row ordered, not column ordered as in VB 6 and Fortran. This means that arrays will need to be transposed for correct interpretation by a Fortran routine.
Because of the different array storage, the "leading dimension" of a Fortran routine will be the second dimension of the VB array. For example A(2,3) in VB.NET would pass 4 as the "leading dimension"; noting that this is because arrays start from index 0

4.12. Calling the DLLs from Delphi

The Fortran DLLs may be called from Delphi programs.

Examples of use of the DLLs from Delphi are given in the .\samples\delphi_examples directory. The file readme.txt in the .\samples\delphi\e04ucf\console directory indicates how to use the Delphi in a console window.

Key information:

Actual arguments must be of type var, since Fortran arguments are passed by reference.
The NAG name must be in capital letters, since this is the name exported from the DLL.
STDCALL calling convention must be used.
Pascal arrays are stored by row; Fortran arrays are stored by column, so array transposition is required to use Pascal arrays with the library DLL.
Character arguments must be null terminated strings, followed immediately afterwards by an additional parameter, the length of the string.

4.13. Example Programs

The example programs are most easily accessed by using the batch file nagex.bat, which will provide you with a copy of an example program (and its data, if any), compile the program and link it with the library. Finally, the executable program will be run. If a compiler other than Compaq Visual Fortran is to be used then the batch file will need to be altered appropriately.

The example program concerned is specified by the argument to nagex.bat. For example, if the location of nagex.bat is on your path, create the directory c:\test, make c:\test the current directory and then give the command:

nagex c06eaf

This will copy the example program and its data into the directory c:\test and process them to produce the example program results in the file c06eafe.res. Please note that the environment variables DLLDTDIR needs to be set as described in the Installer's Note in order for nagex.bat to run successfully.

In the online documentation, routine documents present the example programs in a generalised form, using bold italicised terms as described in Section 4.14.

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.

4.14. Interpretation of Bold Italicised Terms

For this double precision implementation, the bold italicised terms used in the NAG Fortran Library Manual should be interpreted as:

real                 - DOUBLE PRECISION or REAL (KIND(0.0D0))
basic precision      - double precision
complex              - COMPLEX*16 or COMPLEX (KIND(0.0D0)) 
additional precision - quadruple precision (REAL*16)
machine precision    - the machine precision, see the value
                       returned by X02AJF in Section 5

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.

Additional bold italicised terms are used in the example programs in the online documentation 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

4.15. Explicit Output from NAG Routines

Certain routines produce explicit error messages and advisory messages via output units which either have default values or can normally be reset by using X04AAF for error messages and X04ABF for advisory messages. (The default values are given in Section 5.) The maximum record lengths of error messages and advisory messages (including carriage control characters) are 80 characters, except where otherwise specified.

4.16. Interface Blocks

The NAG Fortran Library Interface Blocks define the type and arguments of each user callable NAG Fortran Library routine. These are not essential for calling the NAG Fortran Library. Their purpose is to allow a Fortran 90 compiler (such as the Compaq Visual Fortran compiler) to check that NAG Fortran Library routines are called correctly. The interface blocks enable the compiler to check that:

(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

The interface blocks were 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 generally more reliable than individually written declarations.

The NAG Fortran Library Interface Block files consist of 11 separate modules. Their 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_chapter

These are supplied in pre-compiled form (.mod files). If you are compiling on the command line, to make one or more files accessible you should either copy them to the current directory or ensure that the directory containing the .mod files has been added to the INCLUDE environment variable.

If you are using Developer Studio, you should find that the installation procedure has made Developer Studio aware of the location of the NAG interface blocks. You can confirm that this has been successful by examining the Directories pane when Tools/Options/Directories/Show directories for/Include files has been selected. If the installation had difficulty, perhaps because several versions of Developer Studio were recorded in the registry, then you can set this facility manually in the Directories pane. Otherwise, after establishing a workspace you should make the system aware of any interface blocks by clicking on Project, then Settings, then Fortran, choosing Preprocessor in the Category menu and entering the full paths to the interface blocks in the box labelled INCLUDE and USE Paths.

In order to make use of these modules from existing Fortran 77 code the following changes need to be made:

Add a USE statement for each of the module files for the chapters of the NAG Fortran Library that your program calls directly. Often only one USE statement will be required.
Delete all EXTERNAL statements for NAG Fortran Library routines. These are now declared in the module(s).
Delete the type declarations for any NAG Fortran Library functions. These are now declared in the module(s).

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

4.17 Thread Safety

This library has not been compiled with thread safe switches and is not suitable for use in multiple threaded applications. A separate implementation, FLDLL204T, is available for users interested in developing multiple threaded applications. 5. Routine-specific Information

5. Routine-specific Information

Any further information which applies to one or more routines in this implementation is listed below, chapter by chapter.

(a) F06, F07 and F08

In this implementation calls to the Basic Linear Algebra Subprograms (BLAS) and LAPACK routines are implemented by calls to the Intel MKL Library.

Four routines, F08WHF, F08WJF, F08WVF and F08WWF, will return a slightly different error indicator to that of their LAPACK equivalents if called with a faulty actual argument. NAG believes that the indicator returned by the F08 routines is more informative and have reported the revision to the LAPACK authors.

(b) G02

The value of ACC, the machine-dependent constant mentioned in several documents in the chapter, is 1.0D-13.

(c) P01

On hard failure, P01ABF writes the error message to the error message unit specified by X04AAF and then stops.

(d) S07 - S21

The constants referred to in the NAG Fortran Library Manual have the following values in this implementation:

S07AAF  F(1)   = 1.0D+13
        F(2)   = 1.0D-14
S10AAF  E(1)   = 1.8500D+1
S10ABF  E(1)   = 7.080D+2
S10ACF  E(1)   = 7.080D+2
S13AAF  x(hi)  = 7.083D+2
S13ACF  x(hi)  = 1.0D+16
S13ADF  x(hi)  = 1.0D+17
S14AAF  IFAIL  = 1 if X > 1.70D+2
        IFAIL  = 2 if X < -1.70D+2
        IFAIL  = 3 if abs(X) < 2.23D-308
S14ABF  IFAIL  = 2 if X > 2.55D+305
S15ADF  x(hi)  = 2.66D+1
        x(low) = -6.25D+0
S15AEF  x(hi)  = 6.25D+0
S17ACF  IFAIL  = 1 if X > 1.0D+16
S17ADF  IFAIL  = 1 if X > 1.0D+16
        IFAIL  = 3 if 0.0D+00 < 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 > 1.038D+2
        IFAIL  = 2 if X < -5.6D+10
S17AHF  IFAIL  = 1 if X > 1.041D+2
        IFAIL  = 2 if X < -5.6D+10
S17AJF  IFAIL  = 1 if X > 1.041D+2
        IFAIL  = 2 if X < -1.8D+9
S17AKF  IFAIL  = 1 if X > 1.041D+2
        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) > 7.00D+2
        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 0.0D+00 < X <= 2.23D-308
S18AEF  IFAIL  = 1 if abs(X) > 7.116D+2
S18AFF  IFAIL  = 1 if abs(X) > 7.116D+2
S18CDF  IFAIL  = 2 if 0.0D+00 < 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) > 7.00D+2
        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) >= 4.95000D+1
S19ABF  IFAIL  = 1 if abs(x) >= 4.95000D+1
S19ACF  IFAIL  = 1 if X > 9.9726D+2
S19ADF  IFAIL  = 1 if X > 9.9726D+2
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

(e) X01

The values of the mathematical constants are:

X01AAF (PI)    = 3.1415926535897932D+00
X01ABF (GAMMA) = 0.5772156649015329D+00

(f) X02

The values of the machine constants are:

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'43F0000000000000' ( 1.84467440737095D+19 )
X02BBF = 2147483647
X02BEF = 15
X02DAF = .FALSE.

(g) X04

The default output units for error and advisory messages for those routines which can produce explicit output are both Fortran Unit 6.

5. Documentation

6.1. Online Documentation

The NAG Fortran Library documentation is provided as Portable Document Format (PDF) files, with an HTML index, in the .\doc\manual20 directory. The introductory material is also provided as HTML files via the .\doc\manual20\html\mark20.html index.

You are advised to consult the introductory materials before calling any routine.

Essential Introduction - describes the structure of the library and its documentation, and gives basic advice on using the library
Mark 20 News - an outline of the new and enhanced routines available at Mark 20
Library Contents - a brief summary of the routines provided
Withdrawn Routines
Advice on Replacement Calls for Withdrawn/Superseded Routines

In addition the following are provided in the .\doc directory

blas_lapack_to_nag - BLAS/F06, LAPACK/F07 and LAPACK/F08 listing
nag_to_blas_lapack - F06/BLAS, F07/LAPACK and F08/LAPACK listing

6.2 Printed Documentation

Printed copies of the NAG Fortran Library Manual are available for purchase; please refer to the NAG documentation order form (available on the NAG websites) for details of current prices.

7. Support from NAG

(a) Contact with NAG

Queries concerning this document or the implementation generally should be directed initially to your local Advisory Service. If you have difficulty in making contact locally, you can contact NAG directly at one of the addresses given in the Appendix. Users subscribing to the support service are encouraged to contact one of the NAG Response Centres (see below).

(b) NAG Response Centres

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. (This is given at the head of this document.)

(c) NAG Websites

The NAG websites are 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 websites can be accessed at
http://www.nag.co.uk/ , http://www.nag.com/ (in North America) or http://www.nag-j.co.jp/ (in Japan)

(d) NAG Electronic Newsletter

If you would like to be kept up to date with news from NAG you may want to register to receive our electronic newsletter, which will alert you to special offers, announcements about new products or product/service enhancements, case studies and NAG's event diary. To register simply visit one of our websites or contact us at nagnews@nag.co.uk.

8. User Feedback

Many factors influence the way NAG's products and services evolve and your ideas are invaluable in helping us to ensure that we meet your needs. If you would like to contribute to this process we would be pleased to receive your comments by email at feedback@nag.co.uk. Alternatively feel free to contact the appropriate NAG Response Centre who will be happy to record your comments.

Appendix - Contact Addresses

NAG Ltd
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Tel: +44 (0)1865 511245                 Tel: +44 (0)1865 311744
Fax: +44 (0)1865 310139                 Fax: +44 (0)1865 310139
 
NAG Inc
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Downers Grove
IL 60515-1362                           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 2706
 
Nihon NAG KK
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4-9-9
Hatchobori
Chuo-ku
Tokyo
104-0032
Japan
email: help@nag-j.co.jp

Tel: +81 (0)3 5542 6311
Fax: +81 (0)3 5542 6312