Smearing/Desmearing using Weighting Matrix Method for USANS Data

[ajj]

We should use the weighting matrix method as described by Singh et al
and as used by JGB on the microVAX in the IGOR routines.

This is in:
1) Desmearing of data - lake method used currently works fine so this is
probably not a huge priority.

2) Smearing of model data - current numerical integration is very slow
if the model itself has one or more integrals to calculate (e.g.
polydisperse spheres or ellipsoids). This is more of a priority if we
are to encourage users to actually fit their USANS data!

From: ​http://rt.ncnr.nist.gov/Ticket/Display.html?id=758

[ajj]

Replying to ajj:

This will need an overhaul of the way that resolution waves are used in
the fitting routines. At the moment, the most recent resolution wave is
used. We probably need a method whereby a wavenote is created to
indicate the name of the resolution wave and then the correct wave can
be used in the smearing calculation. This is probably best done by just
putting the wave prefix in the wavenote - then we actually have access
to all the wavenames for each dataset.

Along with this, the weighting matrix for each data set will have to be
calculated. This can take a little while, so it might be good to do it
in the background, now that IGOR 6 supports background threads, and thus
avoiding the user having to wait on each load.

[ajj]

Replying to ajj:

SRK has indicated that IGOR 6 now supports passing a structure to All-at-once fit functions. This would be the better way of doing things as it avoids monkeying around with wavenotes. We could pass a structure of parameters and resolution wave.

[ajj]

This code is now going in to the development branch of analysis (source:/sans/branches/ajj_23APR07).

Functions have become AAO and work on getting structures is underway.

Fitting and smearing are currently broken.

[ajj]

This feature is now done [162]. Other tickets deal with issues arising from its incorporation.