Re: [Quantlib-dev] qlxl dependencies and object updates

[Eric E. <eri...@na...>]

Hi Peter,

> However, if I recompute e.g. cell a2 (the first rate helper) and a9
> afterwards, I see the same effect, i.e. the yield curve object seems to
> have received a notification from the recomputed rate helper object? I
> thought that recomputation of a cell containing a ql-constructor creates a
> new object using the constructor and deletes the previous version of the
> object? Obviously this is not the case, but something smarter is going on.
> Could you briefly explain please?

ObjectHandler has some extra logic to ensure that objects are always  
kept up to date.

For various reasons OH keeps track of all of the relationships between  
objects.  When an object is retrieved, OH verifies that the object is  
newer than its precedents and if not the object is recreated.  This  
relies on an implementation of the Observer/Observable pattern which  
is local to OH and separate from QuantLib's use of the same pattern.   
This logic in OH is also independent of Excel.  For more detail see  
class ObjectWrapper.

I recreated your test for the memory leak and was not immediately able  
to find an explanation or a solution, I continue to investigate and  
will keep you posted.  Many thanks for your feedback.

Kind Regards,
Eric

===================================================
Eric Ehlers
nazcatech sprl | Brussels | http://www.nazcatech.be
* Distributed computing for pricing analytics
* Use Microsoft Excel as a client to the Grid