The majority of parameters are either scalar or arrays of type Int32 and Double, or the Complex type described below. Exceptions to this, where methods have parameters of types defined within the library, are described in the next secton.

Complex

The Complex class is defined by:

public Complex(double r, double i)
{
 re = r;
 im = i;
}

Several methods are defined to allow convertion between complex values to and strings. The type inherits the IFormattable interface so Complex values may be formatted in Console.Write and similar methods. The format specified is applied separately to each of the real and imaginary parts. The Complex class also has several overloaded operators for the standard arithmetic operations.

DataReader

The DataReader is a small wrapper around the standard StreamReader class. It serves two functions.

1. It provides methods for parsing streams containing ASCII data in the formats used in the NAG example programs. This feature may be of limited use in other contexts.
2. A DataReader may be used to hold a stream consisting of several option setting strings, one per line. the option setting classes described below have an overloaded Set method, which if passed a DataReader stream will extract each option setting line and call the appropriate option Set method on the resulting string. See the example below setting options in an E05 example.

There are some chapters of the NAG Library where we have not kept to strictly one to one mapping of Fortran routines to .NET methods. These are described below.

C05

In contrast to many methods in the NAG Library which require function parameters (delegates), some methods in this class obtain the information required by repeatedly returning to the calling program. In these cases information has to be stored in an intermediate communication class which can then be passed as a parameter to the appropriate C05 method. e.g.

C05.c05ndCommunications communications  = new C05.c05ndCommunications(n);
C05.c05nd(ref irevcm, n, x, fvec, xtol, ml, mu, epsfcn, mode, diag, factor, fjac, r, qtf,
          communications, out ifail );

C09

In the C09 class the methods follow a pattern in which there is an initialisation phase which collects information that is subsequently used by other class methods. Here the initialisation is carried out by the C09Communications class and the resultant object is passed as a parameter to the following method call.

C09.C09Communications c09comm = new C09.C09Communications(wavnam, wtrans, mode, n, out ifail);
C09.c09cc(n, x, c, dwtlev, c09comm, out ifail);

E04

In the E04 class, the optimization methods can be fine tuned by a large number of parameters which generally have default values. Consequently there is an initialisation phase associated with these methods. The initialisation is carried out by a method related options class. The Set method of the options class can then be used to provide set additional parameters. e.g.

E04.e04ucOptions options = new E04.e04ucOptions();
options.Set("List");
E04.e04uc(n, nclin, ncnln, a, bl, bu, confunE04UCA, objfunE04UCA, out iter, istate, c,
          cjac, clamda, out objf, objgrd, r, x, options, out ifail);

E05

In the E05 class, the option handling in E05 is very similar to that of E04. e.g.

sr = new DataReader("../exampledata/e05jbe.d");
E05.e05jbOptions options = new E05.e05jbOptions();
options.Set(sr);
options.Set("Local Searches Limit = 40");
E05.e05jb(n, objfunE05JB, ibound, iinit, bl, bu, list, numpts, initpt, monitE05JB, x, out obj,
           options, out ifail);

G05

In the G05 class, the random number generators have to be initialised to a repeatable or a non-repeatable state and this state information is then communicated to the generator methods. We have provided the G05State class to perform the initialisation; G05State constructs the object which is then passed as a parameter to the required G05 method. e.g.

G05.G05State g05State = new G05.G05State(genid, subid, seed, out ifail);
G05.g05ph(2, n, xmean, ip, phi,iq,theta, avar,r,  g05State, out var, x, out ifail);

The output from library can be categorized into two, error/warning messages and monitoring output mainly from the optimization and statistical methods. This output is directed to the console by default. However, the PrintManager class can be used to direct the output to a stream of the user's choice. The PrintManager class specifies two properties, Warning and Message to allow the user to define separate delegates, one for warning/errors and the other for monitoring.

For example, to switch off both the warnings and monitoring output you could use:

PrintManager.Message = new PrintManager.MessageLogger(discardmessage);
PrintManager.Warning = new PrintManager.MessageLogger(discardmessage);

and define discardmessage as:

static void discardmessage(String message)
{
}

In addition to the static properties on the PrintManager class, which set the global default printing behaviour for the library, the options classes described above also have Warning and Method properties. By setting these properties on instances of an options class the printing behaviour of individual method calls may be controlled.

If a routine can signals an error due to incorrect data input or the underlying algorithm can return a failure, the method will have an ifail parameter. If this parameter has a value of zero on return then the method has succeded. A non-zero value almost always indicates failure, however sometimes the answers are acceptable, in particular many methods in E04 may return acceptable results despite a non zero ifail warning. The accompanying message should make it clear whether a non-zero return of ifail is acceptable. We have chosen to use return values of ifail rather than throw exceptions ourselves to allow you the opportunity to throw appropriate exceptions based on your application's requirements.

Please check the following URL:

http://www.nag.co.uk/doc/inun/dt02/w3adal/postrelease.html

for details of any new information related to the applicability or usage of this implementation.

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