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notes:dan:contrast-matrix [2022/03/20 08:07] โ cjj | notes:dan:contrast-matrix [2022/03/20 08:37] (current) โ cjj | ||
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\begin{eqnarray*} | \begin{eqnarray*} | ||
\mathrm{Err}_{\mathrm{restr}} & = & \mathbf{r}_{\mathrm{restr}}^{T}\mathbf{r}_{\mathrm{restr}}\\ | \mathrm{Err}_{\mathrm{restr}} & = & \mathbf{r}_{\mathrm{restr}}^{T}\mathbf{r}_{\mathrm{restr}}\\ | ||
- | & = & \mathbf{r}_{\mathrm{full}}^{T}\mathbf{r}_{\mathrm{full}}+\left(\widehat{๐}-๐_{0}\right)^{T}\mathbf{X}^{T}\mathbf{X}\left(\widehat{๐}-๐_{0}\right)\\ย | + | & = & \mathbf{r}_{\mathrm{full}}^{T}\mathbf{r}_{\mathrm{full}}+\left(\widehat{๐}-๐_{0}\right)^{T}\color{# |
- | & = & \mathrm{Err}_{\mathrm{full}}+\left(\widehat{๐}-๐_{0}\right)^{T}\mathbf{L}^{T}\left(\mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T}\right)^{-1}\left(\mathbf{L}\widehat{๐}-\mathbf{c}\right)\\ย | + | & = & \mathrm{Err}_{\mathrm{full}}+\color{# |
- | & = & \mathrm{Err}_{\mathrm{full}}+\left(\mathbf{L}\widehat{๐}-\mathbf{c}\right)^{T}\left(\mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T}\right)^{-1}\\ย | + | & = & \mathrm{Err}_{\mathrm{full}}+\color{# |
- | & & \times\mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T}\left(\mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T}\right)^{-1}\left(\mathbf{L}\widehat{๐}-\mathbf{c}\right)\\ | + | & & \times\mathbf{L}^{T}\left(\mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T}\right)^{-1}\left(\mathbf{L}\widehat{๐}-\mathbf{c}\right)\\ |
& = & \mathrm{Err}_{\mathrm{full}}+\left(\mathbf{L}\widehat{๐}-\mathbf{c}\right)^{T}\left(\mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T}\right)^{-1}\left(\mathbf{L}\widehat{๐}-\mathbf{c}\right) | & = & \mathrm{Err}_{\mathrm{full}}+\left(\mathbf{L}\widehat{๐}-\mathbf{c}\right)^{T}\left(\mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T}\right)^{-1}\left(\mathbf{L}\widehat{๐}-\mathbf{c}\right) | ||
\end{eqnarray*} | \end{eqnarray*} | ||
where the cross terms vanish since $ \mathbf{X}^{T}\mathbf{r}_{\mathrm{full}} = 0 $ by the condition of the full model, and we observe that $ \mathbf{X}^{T}\mathbf{X} $ and $ \mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T} $ are both symmetric matrices. | where the cross terms vanish since $ \mathbf{X}^{T}\mathbf{r}_{\mathrm{full}} = 0 $ by the condition of the full model, and we observe that $ \mathbf{X}^{T}\mathbf{X} $ and $ \mathbf{L}\left(\mathbf{X}^{T}\mathbf{X}\right)^{-1}\mathbf{L}^{T} $ are both symmetric matrices. |