From 7349e4a2548d5a22bd6f472cb76a7a8434167fc5 Mon Sep 17 00:00:00 2001
From: Mo Chen <sth4nth@gmail.com>
Date: Mon, 12 Mar 2018 03:11:38 +0800
Subject: [PATCH] minor improvements

---
 chapter09/linRegEm.m  | 10 +++++-----
 chapter10/linRegVb.m  |  2 +-
 chapter10/rvmRegVb.m  |  2 +-
 chapter14/mixLinReg.m |  1 -
 4 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/chapter09/linRegEm.m b/chapter09/linRegEm.m
index 00280fe..5534bfa 100644
--- a/chapter09/linRegEm.m
+++ b/chapter09/linRegEm.m
@@ -14,7 +14,7 @@
     beta = 0.5;
 end
 [d,n] = size(X);
-
+I = eye(d);
 xbar = mean(X,2);
 tbar = mean(t,2);
 
@@ -39,12 +39,12 @@
     llh(iter) = 0.5*(d*log(alpha)+n*log(beta)-alpha*m2-beta*e2-logdetA-n*log(2*pi));  % 3.86
     if abs(llh(iter)-llh(iter-1)) < tol*abs(llh(iter-1)); break; end
     
-    V = inv(U);
-    trS = dot(V(:),V(:));    % A=inv(S)
+    invU = U'\I;
+    trS = dot(invU(:),invU(:));    % A=inv(S)
     alpha = d/(m2+trS);   % 9.63
     
-    UX = U'\X;
-    trXSX = dot(UX(:),UX(:));
+    invUX = U'\X;
+    trXSX = dot(invUX(:),invUX(:));
     beta = n/(e2+trXSX);  % 9.68 is wrong
 end
 w0 = tbar-dot(m,xbar);
diff --git a/chapter10/linRegVb.m b/chapter10/linRegVb.m
index 49ba81e..809c3fa 100644
--- a/chapter10/linRegVb.m
+++ b/chapter10/linRegVb.m
@@ -8,7 +8,6 @@
 %   model: trained model structure
 %   energy: variational lower bound
 % Written by Mo Chen (sth4nth@gmail.com).
-[m,n] = size(X);
 if nargin < 3
     a0 = 1e-4;
     b0 = 1e-4;
@@ -20,6 +19,7 @@
     c0 = prior.c;
     d0 = prior.d;
 end
+[m,n] = size(X);
 I = eye(m);
 xbar = mean(X,2);
 tbar = mean(t,2);
diff --git a/chapter10/rvmRegVb.m b/chapter10/rvmRegVb.m
index 2ced2d7..91d073b 100644
--- a/chapter10/rvmRegVb.m
+++ b/chapter10/rvmRegVb.m
@@ -8,7 +8,6 @@
 %   model: trained model structure
 %   energy: variational lower bound
 % Written by Mo Chen (sth4nth@gmail.com).
-[m,n] = size(X);
 if nargin < 3
     a0 = 1e-4;
     b0 = 1e-4;
@@ -20,6 +19,7 @@
     c0 = prior.c;
     d0 = prior.d;
 end
+[m,n] = size(X);
 idx = (1:m)';
 dg = sub2ind([m,m],idx,idx);
 I = eye(m);
diff --git a/chapter14/mixLinReg.m b/chapter14/mixLinReg.m
index aa530f5..7bf90cb 100644
--- a/chapter14/mixLinReg.m
+++ b/chapter14/mixLinReg.m
@@ -45,7 +45,6 @@
     if abs(llh(iter)-llh(iter-1)) < tol*abs(llh(iter)); break; end
 end
 llh = llh(2:iter);
-label = max(R,[],1);
 model.alpha = alpha; % mixing coefficient
 model.beta = beta; % mixture component precision
 model.W = W;  % linear model coefficent