From f618466c25d43f3bae9e40920273bf77de1e1149 Mon Sep 17 00:00:00 2001
From: leochanj105 <leochanj@live.unc.edu>
Date: Mon, 19 Oct 2020 23:09:30 -0400
Subject: initial sd-vbs

initial sd-vbs

add sd-vbs

sd-vbs
---
 SD-VBS/common/toolbox/MultiNcut/discretisation.m | 49 ++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100755 SD-VBS/common/toolbox/MultiNcut/discretisation.m

(limited to 'SD-VBS/common/toolbox/MultiNcut/discretisation.m')

diff --git a/SD-VBS/common/toolbox/MultiNcut/discretisation.m b/SD-VBS/common/toolbox/MultiNcut/discretisation.m
new file mode 100755
index 0000000..70b5650
--- /dev/null
+++ b/SD-VBS/common/toolbox/MultiNcut/discretisation.m
@@ -0,0 +1,49 @@
+function [SegLabel,EigenVectors]=discretisation(EigenVectors,nr,nc)
+% 
+% EigenvectorsDiscrete=discretisation(EigenVectors)
+% 
+% Input: EigenVectors = continuous Ncut vector, size = ndata x nbEigenvectors 
+% Output EigenvectorsDiscrete = discrete Ncut vector, size = ndata x nbEigenvectors
+%
+% Timothee Cour, Stella Yu, Jianbo Shi, 2004
+
+[n,k]=size(EigenVectors);
+
+vm = sqrt(sum(EigenVectors.*EigenVectors,2));
+EigenVectors = EigenVectors./repmat(vm,1,k);
+
+R=zeros(k);
+R(:,1)=EigenVectors(1+round(rand(1)*(n-1)),:)';
+c=zeros(n,1);
+for j=2:k
+    c=c+abs(EigenVectors*R(:,j-1));
+    [minimum,i]=min(c);
+    R(:,j)=EigenVectors(i,:)';
+end
+
+lastObjectiveValue=0;
+exitLoop=0;
+nbIterationsDiscretisation = 0;
+nbIterationsDiscretisationMax = 20;%voir
+while exitLoop== 0 
+    nbIterationsDiscretisation = nbIterationsDiscretisation + 1 ;   
+    EigenvectorsDiscrete = discretisationEigenVectorData(EigenVectors*R);
+    [U,S,V] = svd(EigenvectorsDiscrete'*EigenVectors,0);    
+    NcutValue=2*(n-trace(S));
+    
+    if abs(NcutValue-lastObjectiveValue) < eps | nbIterationsDiscretisation > nbIterationsDiscretisationMax
+        exitLoop=1;
+    else
+        lastObjectiveValue = NcutValue;
+        R=V*U';
+    end
+end
+
+%%%%
+
+SegLabel = zeros(nr,nc);
+for j=1:size(EigenvectorsDiscrete,2),
+        SegLabel = SegLabel + j*reshape(EigenvectorsDiscrete(:,j),nr,nc);
+end
+EigenVectors = reshape(EigenVectors,nr,nc,size(EigenVectors,2));
+
-- 
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