open source pkg v1

pkg/OpenFace/matlab_version/CCNF/CalcSigmaCCNFflat.m

@@ -0,0 +1,57 @@
+function [ SigmaInv] = CalcSigmaCCNFflat(alphas, betas, n, precalcQ2withoutBeta, precalc_eye, precalc_zeros)
+%CALCSIGMAPRF Summary of this function goes here
+%   Detailed explanation goes here
+% constructing the sigma
+ 
+%     A = zeros(n);
+%          
+%     for i=1:n
+% 
+%         A(i,i) = alphas' * mask(i,:)';
+% 
+%     end
+
+    % this is simplification of above code
+%     if(useIndicators)
+%         A = diag(mask * alphas);
+%     else
+
+%         A = sum(alphas) .* eye(n);
+        A = sum(alphas) .* precalc_eye;
+%         A = sum(alphas) * eye(n);
+        % not faster
+%         a = mtimesx(sum(alphas), eye(n), 'SPEED');
+%         a2 = mtimesx(sum(alphas), eye(n), 'SPEEDOMP');
+%     end
+        
+    % calculating the B from the paper
+    
+%     for i=1:n
+%         for j=1:n
+% 
+%             if(i == j)
+%                 q2(i,j) = beta * (sum(S(i,:)) - S(i,i));
+%             else
+%                 q2(i,j) = -beta * S(i,j);
+%             end
+%         end            
+%     end
+
+    % the above code can be simplified by the following lines of code     
+    % using the precalculated lower triangular elements of B without beta
+    Btmp = precalcQ2withoutBeta * betas;        
+    % not faster
+%     Btmp = mtimesx(precalcQ2withoutBeta, betas, 'SPEED');
+%     Btmp = mtimesx(precalcQ2withoutBeta, betas, 'SPEEDOMP');
+    % now make it into a square symmetric matrix
+%     B = zeros(n,n);
+    B = precalc_zeros;
+    on = tril(true(n,n));
+    B(on) = Btmp;
+    B = B';
+    B(on) = Btmp;
+    
+    SigmaInv = 2 * (A + B);
+
+end
+