groupStruct

Group a struct-array by the nominal values (which will be created) for the fields you specify. Returns a grouped struct, a cell-array containing the different groups, a cell-array with the nominal values that were used, a cell-array with the fields that were used, and a cell-array with the indexes from the original struct corresponding to the one used in the groups.
If you for instance have a struct-array with experimental data with different inclinations (PHI) and velocities (V) you can use the following example to group the experiments by the nominal values for the fields PHI and V:

%Create some artificial experimental data
s=struct;
s.PHI=0;
s.V=1.1;
s(end+1).PHI=1;
s(end).V=1.082;
s(end+1).PHI=0;
s(end).V=1.084;
s(end+1).PHI=1;
s(end).V=0.61;
s(end+1).PHI=1;
s(end).V=0.58;
s(end+1).PHI=0;
s(end).V=0.598;
s(end+1).PHI=0;
s(end).V=1.12;

%Group the struct by PHI and V, using 5% as tolerance when creating nominal values for both PHI and V.
[sOut,groups,nomsOut,ids,inds] = groupStruct( s, {'PHI','V'}, [0.05,0.05] );

Requires the 'nominal' function, and the 'getarg' function.