I'm still leaning towards requiring some public constraint interface. The
A model would have a list of constraints. A constraint would have a constraint
> On 2004.06.07 14:38,
[hidden email] wrote:
> > BTW, does anyone know how to set things so that additional
> > constraints apply to the G2 parameters when fitting (outside of
> > changing code for G2 constructor)?
> > For example, if I wanted to set boundary conditions for a to be in
> > range (0.0-0.05). I can"t work out how to do it otherwise.
>
> > Would you need to add a public interface in the particular model? I
> > see that calibrate in model.cpp has an additional optimization
> > parameter, but I don't know how to relate that back to the model's
> > parameters. Any ideas ?
>
> Mike,
> it's a bit of work, but it can be done. You'll have to define
> your own specific constraint first, as in:
>
> class AConstraint : public Constraint {
> private:
> class Impl : public Constraint::Impl {
> public:
> Impl(Real low, Real high)
> : low_(low), high_(high) {}
> bool test(const Array& params) const {
> // a is parameter # 0 in G2
> return ((params[0] > low_) && (params[0] < high_))
> }
> private:
> Real low_, high_;
> };
> public:
> AConstraint(Real low, Real high)
> : Constraint(boost::shared_ptr<Constraint::Impl>(
> new AConstraint::Impl(low, high))) {}
> };
>
> There's a bit of machinery involved---mainly because Constraint is
> implemented via the Strategy pattern, which might or might not be the
> right choice in this case---but the point is that test() should return
> true if the parameters satisfy the desired constraints and false
> otherwise. You can easily extend the above so that it checks more
> parameters.
>
> Afterwards, you should be able to do
>
> G2 model(...);
> model.calibrate(helpers, method, AConstraint(0.0,0.05));
>
> and the calibration should take into account your constraint besides
> the ones intrinsic to the model.
>
> Hope this helps,
> Luigi
>