diff --git a/M1_biosciences_clustering/kmeans.tex b/M1_biosciences_clustering/kmeans.tex index 455d9fcd44b535efd8fb7b9444b050e346aef6ad..e1836ce8a997392b7d880949b39e02880c77b1b5 100644 --- a/M1_biosciences_clustering/kmeans.tex +++ b/M1_biosciences_clustering/kmeans.tex @@ -37,7 +37,7 @@ $$ $$ \item Step $[h+1]$: update labels $\zbf$ when centers $\overline{\xbf}_1^{[h+1]},\hdots,\overline{\xbf}_K^{[h+1]}$ are updated $$ -\widehat{z}_{i}^{[h]} = \arg \underset{1,\hdots,K}{\min} \left\{ d^2(\xbf_i,\overline{\xbf}_k^{[h+1]}) \right\} +\widehat{z}_{i}^{[h+1]} = \arg \underset{1,\hdots,K}{\min} \left\{ d^2(\xbf_i,\overline{\xbf}_k^{[h+1]}) \right\} $$ \end{itemize} @@ -55,22 +55,22 @@ $$ \frametitle{Decreasing inertia} \begin{itemize} \item Denoting by $[h]$ the step $h$ of the algorithm, $\zbf^{[h]}, - \xbf^{[h]}$ - \item The inertia depends on both quantities $\Ibf_W(\zbf^{[h]},\xbf^{[h]})$ + \overline{\xbf}^{[h]}$ + \item The inertia depends on both quantities $\Ibf_W(\zbf^{[h]},\overline{\xbf}^{[h]})$ \item Updating centers $$ - \Ibf_W(\zbf^{[h]},\xbf^{[h+1]}) = \sum_{i=1}^n \sum_{k=1}^K z_{ik}^{[h]} + \Ibf_W(\zbf^{[h]},\overline{\xbf}^{[h+1]}) = \sum_{i=1}^n \sum_{k=1}^K z_{ik}^{[h]} d^2(\xbf_i,\overline{\xbf}_k^{[h+1]}) $$ \item Updating labels $$ - \Ibf_W(\zbf^{[h+1]},\xbf^{[h+1]}) = \sum_{i=1}^n \sum_{k=1}^K z_{ik}^{[h+1]} + \Ibf_W(\zbf^{[h+1]},\overline{\xbf}^{[h+1]}) = \sum_{i=1}^n \sum_{k=1}^K z_{ik}^{[h+1]} d^2(\xbf_i,\overline{\xbf}_k^{[h+1]}) $$ \item The criterion decreases at each step $$ - \Ibf_W(\zbf^{[h]},\xbf^{[h]}) \geq \Ibf_W(\zbf^{[h]},\xbf^{[h+1]}) \geq - \Ibf_W(\zbf^{[h+1]},\xbf^{[h+1]})$$ + \Ibf_W(\zbf^{[h]},\overline{\xbf}^{[h]}) \geq \Ibf_W(\zbf^{[h]},\overline{\xbf}^{[h+1]}) \geq + \Ibf_W(\zbf^{[h+1]},\overline{\xbf}^{[h+1]})$$ \end{itemize} \end{frame}