CompiledParam.h

Given a string describing an expression (see FuncExpression class for details of the expression), the CompiledFunctionclass wraps this expression as a Function (see Function class) which can be used in all places where functions can be used (e.g. see Fitting).

This class takes care of the CompiledFunction parameter interface (see FunctionParam class for details).

Example

In the following example a Gaussian profile with three parameters (height, center and halfwidth) is specified and its value and derivatives with respect to the parameters are calculated at x=2.

    // the Gaussian
    CompiledFunction<Double> prof("p0*exp(-((x-p1)/p2)^2)");
    prof[0] = 2;				// the height
    prof[1] = 1.5;			// the center
    prof[2] = 1;				// the width
    Vector<Double> x(3);
    X[0] = 1.9; x[1] = 2.0; x[2] = 2.1;
    cout << "Gaussian at x=" << x << ": " << prof(x) << endl;
    // and an automatic derivative one:
    CompiledFunction<AutoDiff<Double> > profad("p0*exp(-((x-p1)/p2)^2)");
    cout << "Gaussian at x=" << x << ": " << profad(x) << endl;

will produce the output:

Template Type Argument Requirements (T)

T should have standard numerical operators and functions.
To obtain derivatives, the derivatives should be defined.

Thrown Exceptions

Motivation

This class was created to allow specialization of the function evaluation in a simple way.

To Do

Nothing I know of

Member Description

CompiledParam()

The default constructor -- no functions, no parameters, nothing, the function operator returns a 0.

CompiledParam(const CompiledParam<T> &other)

Make this object a (deep) copy of other.

CompiledParam<T> &operator=(const CompiledParam<T> &other)

Make this object a (deep) copy of other.

virtual ~CompiledParam()

Destructor

Bool setFunction(const String &newFunction)

Set a function. The return will be False (and an error message will be set) if a compilation error occurs

const String &errorMessage() const

Return the error message of the compilation

const FuncExpression &function() const

Return the expression

virtual uInt ndim() const

Returns the dimension of function

const String &getText() const

Returns the text of the function string