pFunction.h

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// pFunction: An interface for PFunctions in PRISMS-PF
// This class is used to declare and load PFunctions from a pre-existing PLibrary
// that was created using PRISMS IntegrationTools. The class is a wrapper for the
// PFunctions in IntegrationTools so that they can be used for vectorized arrays.
// This class also calls the IntegrationTools checkout function in the constructor
// to reduce the number of steps the user needs to take. Currently this is only
// implemented for scalar functions. Vector functions can be treated component by
// component.

namespace PFunctions{

class pFunction
{
public:
    // Constructor, wraps the IntegrationTools checkout function
    pFunction(std::string function_name);

    // Returns the value of the function for a given input variable
    scalarvalueType val(scalarvalueType);

    // Returns one of first derivatives of the function for a given input variable
    scalarvalueType grad(scalarvalueType, unsigned int);

    // Returns one of the second derivatives of the function for a given input variable
    scalarvalueType hess(scalarvalueType, unsigned int, unsigned int);

private:
    PRISMS::PFunction<double*, double> fun;
};

pFunction::pFunction(std::string function_name){
    PRISMS::PLibrary::checkout(function_name, fun);
}

scalarvalueType pFunction::val(scalarvalueType var){
    scalarvalueType fun_val;
    for (unsigned i=0; i < var.n_array_elements; i++){
        fun_val[i] = fun(&var[i]);
    }
    return fun_val;

}


scalarvalueType pFunction::grad(scalarvalueType var,unsigned int dir){
    scalarvalueType fun_grad;
    for (unsigned i=0; i <var.n_array_elements; i++){
        fun_grad[i] = fun.grad(&var[i],dir);
    }
    return fun_grad;

}


scalarvalueType pFunction::hess(scalarvalueType var,unsigned int dir1, unsigned int dir2){
    scalarvalueType fun_hess;
    for (unsigned i=0; i < var.n_array_elements; i++){
        fun_hess[i] = fun.hess(&var[i],dir1,dir2);
    }
    return fun_hess;

}

}