quaternion average of a power two length vector of quaternions

average_quats.m

function [ averagequat ] = average_quats( diffquats )
%AVERAGE_QUATS Average a series of quats, needs to be a two power length
%vector
%   using slrp

range = size(diffquats);
if(range(1) ~= 4)
error 'quaternions must be 4 row vectors'    
end

range = range(2);

%check num quats is power of 2
if(mod(log2(numel(range)),1) > 10 * eps)
    error 'number of quaternions to average must be a power of 2'
end

values = diffquats;
while(1)
    nelem = size(values);
    nelem = nelem(2);
    if(nelem == 1)
        break;
    end
    idx = 1;
    results = zeros(4, nelem / 2);
    for i = 1:2:nelem
        results(:,idx) = slerp(values(:,i), values(:,i + 1), 0.5);  
        idx = idx + 1;
    end
    values = results;
end

averagequat = values;

end