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Daniel Russel wrote:
Ben Webb wrote:
It seems like option (2) would be able to handle this more easily -
either that or we use option (1) together with something like the
DerivativeAccumulator that Keren proposed. Why don't you like option 2?
Option 2 basically is the DerivativeAccumulator. On reflection, I do
like it.
- The restraint has a single evaluate function which takes a pointer to
a DerivativeAccumulator (which is NULL if no derivs are to be
accumulated). No more bool. Can we do this with swig? I would assume
NULL gets translated into null. This has the added advantage that you
can't set derivs if you are not supposed to.
Yes, that should be fine. Python 'None' should go through as a C++ null
pointer. If it doesn't, then it would be easy to write a typemap for.
- To evaluate a restraint (either in the Model or as an outer nested
restraint) you get the weight, w, and tell the DA to multiply its weight
by w (push it on to a stack of weights). Then you call evaluate,
multiply the return value by w and tell the DA to pop the last weight.
- the weights are stored separately from the restraints since they are
no longer handled by the restraint
I don't like stacks like this, for many reasons (threading and exception
safety spring to mind). And I'm not sure where you'd store the weight,
if not in the restraint. Why not just in the Restraint base class?
My alternative to stacks: restraints which contain other restraints
would use a copy-like constructor to make a cloned
DerivativeAccumulator, multiplied by their own weight, and then pass
that to their child restraints' evaluate methods.
Ben
--
http://salilab.org/~ben/
"It is a capital mistake to theorize before one has data."
- Sir Arthur Conan Doyle