functs class for Marginalize-Product-of-Functions (MPF) type computations.

functs is a MATLAB class for Marginalize Product of Functions (MPF) type operations which are commonly encountered in various message passing algorithms such as sum product in probabilistic graphical models (e.g., factor graphs). @functs simply abstracts multidimensional arrays which represent multivariate real functions evaluated over a grid and carries out operations on them.

The class files are under the directory @functs. For examples, please see the test scripts under \test\functs, e.g., run scr_functs_example1.m

The underlying functions are mex (Matlab EXecutables) files under @functs\private and need to be built using the mex utility of MATLAB (after setting up mex, one might run @functs\private\buildarrayfunctions.m). Although these functions could be used on their own, it is much easier to have exploit them through the functs class. After having the mex files built, please run the script
\test\functs\testsuite_functs to verify that the class operates properly.

Example:
In order to abstract the discrete evaluation of a function given by the set description F = {(0,0,5),(1,0,10),(0,1,15),(1,1,20)}, this class offers
>>f = functs({'x','y'},{[0,1]',[0,1]'},[5,10,15,20]');
for the abstraction of F where the first axis of the domain is labelled 'x' and the second axis is called 'y'.
Given two such abstraction along the following lines:
>>f1 = functs({'x','y'},{ X, Y}, R1 ); % abstract function 1
>>f2 = functs({'x','z'},{X, Z}, R2 ); % abstract function 2
The marginalization of the product of these functions is easily computed using the following form:
>>fm = marginalize( f1*f2,{'x'} ); % Find the marginalization of the product of function 1 and 2

Note that this class is created during the research activities and it is WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

The underlying functions used for array multiplication are:
arraymultp.c
arraymultldomp.c
arraysump.c

Please check MATLAB command window help for these functions for further details.
See \test\functs\scr_functs_example1.m for a simple example of how to use this class for Marginalize-Product-of-Functions (MPF) computations.

Note: The testsuit_functs.m clears the workspace in its initial and its final step.