From: Bjørn Rustad <bjorn@rustad.me>
Date: Fri, 30 Sep 2011 13:19:55 +0000 (+0200)
Subject: Fix error in gradient
X-Git-Url: http://git.rustad.me/?a=commitdiff_plain;h=0753a38cadae33e3b1f1a624a65d4705cf993c47;p=nummat1

Fix error in gradient
---

diff --git a/function.py b/function.py
index 480ceb9..5c9cd9f 100644
--- a/function.py
+++ b/function.py
@@ -13,7 +13,7 @@ def _C(x, c):
 
 # Calculate gradient of g in point x
 def gradient_g(x, H, b, c):
-    return -b.T + 0.5 * H.dot(x) + 0.5 * H.T.dot(x) + (1.0/3.0) * x.T.dot(_C(x,c))
+    return -b + H.dot(x) + (1.0/3.0) * _C(x,c).dot(x)
 
 # Calculate hessian of g in point x
 def hessian_g(x, H, b, c):
diff --git a/rapport.tex b/rapport.tex
index 29a90b1..9befc0b 100644
--- a/rapport.tex
+++ b/rapport.tex
@@ -88,18 +88,13 @@ The function analyzed in this project was
 \label{eq:func_g}
 g(\mathbf{x}) := -\mathbf{b}^{T}\mathbf{x}+\frac{1}{2}\mathbf{x}^{T}H\mathbf{x}+\frac{1}{12}\mathbf{x}^{T}C(\mathbf{x})\mathbf{x}
 \end{equation}
-
 From equation \ref{eq:func_g} we get
-
-\begin{equation}
+\begin{eqnarray}
 \label{eq:grad_g}
-\nabla g(\mathbf{x}) = -\mathbf{b}^{T}+H\mathbf{x}+\frac{1}{3}\mathbf{x}^{T}C(\mathbf{x}),
-\end{equation}
-\begin{equation}
+\nabla g(\mathbf{x}) &=& -\mathbf{b}+H\mathbf{x}+\frac{1}{3}C(\mathbf{x})\mathbf{x} \\
 \label{eq:hess_g}
-\nabla^{2}g(\mathbf{x}) = H+C(\mathbf{x}).
-\end{equation}
-
+\nabla^{2}g(\mathbf{x}) &=& H+C(\mathbf{x}).
+\end{eqnarray}
 The three functions, \ref{eq:func_g}, \ref{eq:grad_g} and \ref{eq:hess_g}, are implemented in the Python code below.
 
 \lstinputlisting[language=Python]{bj_function.py}