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qlxl dependencies and object updates

Posted by Peter Caspers-2 on Feb 14, 2011; 8:22pm
URL: http://quantlib.414.s1.nabble.com/qlxl-dependencies-and-object-updates-tp13212.html

Hi qlxl / excel experts,

can somebody help me with the following questions on qlxl (suppose
excels automatic calculation is deactivated):

1. There seems to be a difference between a) updating a cell by
range.calculate b) updating a whole sheet by worksheet.calculate, a)
being "more reliable" than b). That is, sometimes an update of an object
does not force the update of another object one of whose arguments is
the first object using b), but a) will do the trick. Btw a) seems to be
the same as place the cursor on the cell, press F2 and enter. b) same as
pressing shift F9. My guess is that a) recalculates the cell no matter,
if it is "dirty" in excels dependency tree, while b) only recalculates
if a cell is "dirty". That would however imply that excels dependency
tree is not fully reliable?

2. If I have a sheet where I construct an object depending on some input
on the same sheet and these input cells does not change, then the
version of the object is updated every time I press shift F9. Why is
that? Excel should think that no recalculation is necessary, i.e. the
cell should not be dirty in the dependency tree and the version should
not be updated?

3. The trigger argument in constructors: Is that purely dummy forcing a
dependency on excel level or is something done with that parameter in
the object handler?

4. Overwrite: I suppose that not specified means true. When I
recalculate a sheet very often it slows down until it is not usable any
more. My workaround is to call the delete all objects - method in the oh
on a suitable position in the recalculation loop. Then it works fine.
This looks like objects are not overwritten, but new objects are created
on every update?

Thanks for any hints
Peter




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