Files
FYS-STK4155/doc/pub/NeuralNet/html/._NeuralNet-bs019.html
T
2018-09-28 12:11:44 +02:00

298 lines
25 KiB
HTML

<!--
Automatically generated HTML file from DocOnce source
(https://github.com/hplgit/doconce/)
-->
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="DocOnce: https://github.com/hplgit/doconce/" />
<meta name="description" content="Data Analysis and Machine Learning: Elements of machine learning">
<title>Data Analysis and Machine Learning: Elements of machine learning</title>
<!-- Bootstrap style: bootstrap -->
<link href="https://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet">
<!-- not necessary
<link href="https://netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.css" rel="stylesheet">
-->
<style type="text/css">
/* Add scrollbar to dropdown menus in bootstrap navigation bar */
.dropdown-menu {
height: auto;
max-height: 400px;
overflow-x: hidden;
}
/* Adds an invisible element before each target to offset for the navigation
bar */
.anchor::before {
content:"";
display:block;
height:50px; /* fixed header height for style bootstrap */
margin:-50px 0 0; /* negative fixed header height */
}
</style>
</head>
<!-- tocinfo
{'highest level': 2,
'sections': [('Neural networks', 2, None, '___sec0'),
('Artificial neurons', 2, None, '___sec1'),
('Neural network types', 2, None, '___sec2'),
('Feed-forward neural networks', 2, None, '___sec3'),
('Recurrent neural networks', 2, None, '___sec4'),
('Other types of networks', 2, None, '___sec5'),
('Multilayer perceptrons', 2, None, '___sec6'),
('Why multilayer perceptrons?', 2, None, '___sec7'),
('Mathematical model', 2, None, '___sec8'),
('Mathematical model', 2, None, '___sec9'),
('Mathematical model', 2, None, '___sec10'),
('Mathematical model', 2, None, '___sec11'),
('Mathematical model', 2, None, '___sec12'),
('Matrix-vector notation', 3, None, '___sec13'),
('Matrix-vector notation and activation', 3, None, '___sec14'),
('Activation functions', 3, None, '___sec15'),
('Activation functions, Logistic and Hyperbolic ones',
3,
None,
'___sec16'),
('Relevance', 3, None, '___sec17'),
('Setting up a Multi-layer perceptron model',
2,
None,
'___sec18'),
('Two-layer Neural Network', 2, None, '___sec19')]}
end of tocinfo -->
<body>
<script type="text/x-mathjax-config">
MathJax.Hub.Config({
TeX: {
equationNumbers: { autoNumber: "none" },
extensions: ["AMSmath.js", "AMSsymbols.js", "autobold.js", "color.js"]
}
});
</script>
<script type="text/javascript" async
src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>
<!-- Bootstrap navigation bar -->
<div class="navbar navbar-default navbar-fixed-top">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-responsive-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="NeuralNet-bs.html">Data Analysis and Machine Learning: Elements of machine learning</a>
</div>
<div class="navbar-collapse collapse navbar-responsive-collapse">
<ul class="nav navbar-nav navbar-right">
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Contents <b class="caret"></b></a>
<ul class="dropdown-menu">
<!-- navigation toc: --> <li><a href="._NeuralNet-bs001.html#___sec0" style="font-size: 80%;"><b>Neural networks</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs002.html#___sec1" style="font-size: 80%;"><b>Artificial neurons</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs003.html#___sec2" style="font-size: 80%;"><b>Neural network types</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs004.html#___sec3" style="font-size: 80%;"><b>Feed-forward neural networks</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs005.html#___sec4" style="font-size: 80%;"><b>Recurrent neural networks</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs006.html#___sec5" style="font-size: 80%;"><b>Other types of networks</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs007.html#___sec6" style="font-size: 80%;"><b>Multilayer perceptrons</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs008.html#___sec7" style="font-size: 80%;"><b>Why multilayer perceptrons?</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs009.html#___sec8" style="font-size: 80%;"><b>Mathematical model</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs010.html#___sec9" style="font-size: 80%;"><b>Mathematical model</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs011.html#___sec10" style="font-size: 80%;"><b>Mathematical model</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs012.html#___sec11" style="font-size: 80%;"><b>Mathematical model</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs013.html#___sec12" style="font-size: 80%;"><b>Mathematical model</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs014.html#___sec13" style="font-size: 80%;">&nbsp;&nbsp;&nbsp;Matrix-vector notation</a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs015.html#___sec14" style="font-size: 80%;">&nbsp;&nbsp;&nbsp;Matrix-vector notation and activation</a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs016.html#___sec15" style="font-size: 80%;">&nbsp;&nbsp;&nbsp;Activation functions</a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs017.html#___sec16" style="font-size: 80%;">&nbsp;&nbsp;&nbsp;Activation functions, Logistic and Hyperbolic ones</a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs018.html#___sec17" style="font-size: 80%;">&nbsp;&nbsp;&nbsp;Relevance</a></li>
<!-- navigation toc: --> <li><a href="#___sec18" style="font-size: 80%;"><b>Setting up a Multi-layer perceptron model</b></a></li>
<!-- navigation toc: --> <li><a href="._NeuralNet-bs020.html#___sec19" style="font-size: 80%;"><b>Two-layer Neural Network</b></a></li>
</ul>
</li>
</ul>
</div>
</div>
</div> <!-- end of navigation bar -->
<div class="container">
<p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p> <!-- add vertical space -->
<a name="part0019"></a>
<!-- !split -->
<h2 id="___sec18" class="anchor">Setting up a Multi-layer perceptron model </h2>
<p>
<!-- code=python (!bc pycod) typeset with pygments style "default" -->
<div class="highlight" style="background: #f8f8f8"><pre style="line-height: 125%"><span></span><span style="color: #008000; font-weight: bold">from</span> <span style="color: #0000FF; font-weight: bold">scipy</span> <span style="color: #008000; font-weight: bold">import</span> optimize
<span style="color: #008000; font-weight: bold">class</span> <span style="color: #0000FF; font-weight: bold">Neural_Network</span>(<span style="color: #008000">object</span>):
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">__init__</span>(<span style="color: #008000">self</span>, Lambda<span style="color: #666666">=0</span>):
<span style="color: #408080; font-style: italic">#Define Hyperparameters</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>inputLayerSize <span style="color: #666666">=</span> <span style="color: #666666">2</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>outputLayerSize <span style="color: #666666">=</span> <span style="color: #666666">1</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>hiddenLayerSize <span style="color: #666666">=</span> <span style="color: #666666">3</span>
<span style="color: #408080; font-style: italic">#Weights (parameters)</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>W1 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>random<span style="color: #666666">.</span>randn(<span style="color: #008000">self</span><span style="color: #666666">.</span>inputLayerSize,<span style="color: #008000">self</span><span style="color: #666666">.</span>hiddenLayerSize)
<span style="color: #008000">self</span><span style="color: #666666">.</span>W2 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>random<span style="color: #666666">.</span>randn(<span style="color: #008000">self</span><span style="color: #666666">.</span>hiddenLayerSize,<span style="color: #008000">self</span><span style="color: #666666">.</span>outputLayerSize)
<span style="color: #408080; font-style: italic">#Regularization Parameter:</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>Lambda <span style="color: #666666">=</span> Lambda
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">forward</span>(<span style="color: #008000">self</span>, X):
<span style="color: #408080; font-style: italic">#Propogate inputs though network</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>z2 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>dot(X, <span style="color: #008000">self</span><span style="color: #666666">.</span>W1)
<span style="color: #008000">self</span><span style="color: #666666">.</span>a2 <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>sigmoid(<span style="color: #008000">self</span><span style="color: #666666">.</span>z2)
<span style="color: #008000">self</span><span style="color: #666666">.</span>z3 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>dot(<span style="color: #008000">self</span><span style="color: #666666">.</span>a2, <span style="color: #008000">self</span><span style="color: #666666">.</span>W2)
yHat <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>sigmoid(<span style="color: #008000">self</span><span style="color: #666666">.</span>z3)
<span style="color: #008000; font-weight: bold">return</span> yHat
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">sigmoid</span>(<span style="color: #008000">self</span>, z):
<span style="color: #408080; font-style: italic">#Apply sigmoid activation function to scalar, vector, or matrix</span>
<span style="color: #008000; font-weight: bold">return</span> <span style="color: #666666">1/</span>(<span style="color: #666666">1+</span>np<span style="color: #666666">.</span>exp(<span style="color: #666666">-</span>z))
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">sigmoidPrime</span>(<span style="color: #008000">self</span>,z):
<span style="color: #408080; font-style: italic">#Gradient of sigmoid</span>
<span style="color: #008000; font-weight: bold">return</span> np<span style="color: #666666">.</span>exp(<span style="color: #666666">-</span>z)<span style="color: #666666">/</span>((<span style="color: #666666">1+</span>np<span style="color: #666666">.</span>exp(<span style="color: #666666">-</span>z))<span style="color: #666666">**2</span>)
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">costFunction</span>(<span style="color: #008000">self</span>, X, y):
<span style="color: #408080; font-style: italic">#Compute cost for given X,y, use weights already stored in class.</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>yHat <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>forward(X)
J <span style="color: #666666">=</span> <span style="color: #666666">0.5*</span><span style="color: #008000">sum</span>((y<span style="color: #666666">-</span><span style="color: #008000">self</span><span style="color: #666666">.</span>yHat)<span style="color: #666666">**2</span>)<span style="color: #666666">/</span>X<span style="color: #666666">.</span>shape[<span style="color: #666666">0</span>] <span style="color: #666666">+</span> (<span style="color: #008000">self</span><span style="color: #666666">.</span>Lambda<span style="color: #666666">/2</span>)<span style="color: #666666">*</span>(np<span style="color: #666666">.</span>sum(<span style="color: #008000">self</span><span style="color: #666666">.</span>W1<span style="color: #666666">**2</span>)<span style="color: #666666">+</span>np<span style="color: #666666">.</span>sum(<span style="color: #008000">self</span><span style="color: #666666">.</span>W2<span style="color: #666666">**2</span>))
<span style="color: #008000; font-weight: bold">return</span> J
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">costFunctionPrime</span>(<span style="color: #008000">self</span>, X, y):
<span style="color: #408080; font-style: italic">#Compute derivative with respect to W and W2 for a given X and y:</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>yHat <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>forward(X)
delta3 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>multiply(<span style="color: #666666">-</span>(y<span style="color: #666666">-</span><span style="color: #008000">self</span><span style="color: #666666">.</span>yHat), <span style="color: #008000">self</span><span style="color: #666666">.</span>sigmoidPrime(<span style="color: #008000">self</span><span style="color: #666666">.</span>z3))
<span style="color: #408080; font-style: italic">#Add gradient of regularization term:</span>
dJdW2 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>dot(<span style="color: #008000">self</span><span style="color: #666666">.</span>a2<span style="color: #666666">.</span>T, delta3)<span style="color: #666666">/</span>X<span style="color: #666666">.</span>shape[<span style="color: #666666">0</span>] <span style="color: #666666">+</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>Lambda<span style="color: #666666">*</span><span style="color: #008000">self</span><span style="color: #666666">.</span>W2
delta2 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>dot(delta3, <span style="color: #008000">self</span><span style="color: #666666">.</span>W2<span style="color: #666666">.</span>T)<span style="color: #666666">*</span><span style="color: #008000">self</span><span style="color: #666666">.</span>sigmoidPrime(<span style="color: #008000">self</span><span style="color: #666666">.</span>z2)
<span style="color: #408080; font-style: italic">#Add gradient of regularization term:</span>
dJdW1 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>dot(X<span style="color: #666666">.</span>T, delta2)<span style="color: #666666">/</span>X<span style="color: #666666">.</span>shape[<span style="color: #666666">0</span>] <span style="color: #666666">+</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>Lambda<span style="color: #666666">*</span><span style="color: #008000">self</span><span style="color: #666666">.</span>W1
<span style="color: #008000; font-weight: bold">return</span> dJdW1, dJdW2
<span style="color: #408080; font-style: italic">#Helper functions for interacting with other methods/classes</span>
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">getParams</span>(<span style="color: #008000">self</span>):
<span style="color: #408080; font-style: italic">#Get W1 and W2 Rolled into vector:</span>
params <span style="color: #666666">=</span> np<span style="color: #666666">.</span>concatenate((<span style="color: #008000">self</span><span style="color: #666666">.</span>W1<span style="color: #666666">.</span>ravel(), <span style="color: #008000">self</span><span style="color: #666666">.</span>W2<span style="color: #666666">.</span>ravel()))
<span style="color: #008000; font-weight: bold">return</span> params
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">setParams</span>(<span style="color: #008000">self</span>, params):
<span style="color: #408080; font-style: italic">#Set W1 and W2 using single parameter vector:</span>
W1_start <span style="color: #666666">=</span> <span style="color: #666666">0</span>
W1_end <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>hiddenLayerSize<span style="color: #666666">*</span><span style="color: #008000">self</span><span style="color: #666666">.</span>inputLayerSize
<span style="color: #008000">self</span><span style="color: #666666">.</span>W1 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>reshape(params[W1_start:W1_end], \
(<span style="color: #008000">self</span><span style="color: #666666">.</span>inputLayerSize, <span style="color: #008000">self</span><span style="color: #666666">.</span>hiddenLayerSize))
W2_end <span style="color: #666666">=</span> W1_end <span style="color: #666666">+</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>hiddenLayerSize<span style="color: #666666">*</span><span style="color: #008000">self</span><span style="color: #666666">.</span>outputLayerSize
<span style="color: #008000">self</span><span style="color: #666666">.</span>W2 <span style="color: #666666">=</span> np<span style="color: #666666">.</span>reshape(params[W1_end:W2_end], \
(<span style="color: #008000">self</span><span style="color: #666666">.</span>hiddenLayerSize, <span style="color: #008000">self</span><span style="color: #666666">.</span>outputLayerSize))
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">computeGradients</span>(<span style="color: #008000">self</span>, X, y):
dJdW1, dJdW2 <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>costFunctionPrime(X, y)
<span style="color: #008000; font-weight: bold">return</span> np<span style="color: #666666">.</span>concatenate((dJdW1<span style="color: #666666">.</span>ravel(), dJdW2<span style="color: #666666">.</span>ravel()))
<span style="color: #008000; font-weight: bold">class</span> <span style="color: #0000FF; font-weight: bold">trainer</span>(<span style="color: #008000">object</span>):
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">__init__</span>(<span style="color: #008000">self</span>, N):
<span style="color: #408080; font-style: italic">#Make Local reference to network:</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>N <span style="color: #666666">=</span> N
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">callbackF</span>(<span style="color: #008000">self</span>, params):
<span style="color: #008000">self</span><span style="color: #666666">.</span>N<span style="color: #666666">.</span>setParams(params)
<span style="color: #008000">self</span><span style="color: #666666">.</span>J<span style="color: #666666">.</span>append(<span style="color: #008000">self</span><span style="color: #666666">.</span>N<span style="color: #666666">.</span>costFunction(<span style="color: #008000">self</span><span style="color: #666666">.</span>X, <span style="color: #008000">self</span><span style="color: #666666">.</span>y))
<span style="color: #008000">self</span><span style="color: #666666">.</span>testJ<span style="color: #666666">.</span>append(<span style="color: #008000">self</span><span style="color: #666666">.</span>N<span style="color: #666666">.</span>costFunction(<span style="color: #008000">self</span><span style="color: #666666">.</span>testX, <span style="color: #008000">self</span><span style="color: #666666">.</span>testY))
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">costFunctionWrapper</span>(<span style="color: #008000">self</span>, params, X, y):
<span style="color: #008000">self</span><span style="color: #666666">.</span>N<span style="color: #666666">.</span>setParams(params)
cost <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>N<span style="color: #666666">.</span>costFunction(X, y)
grad <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>N<span style="color: #666666">.</span>computeGradients(X,y)
<span style="color: #008000; font-weight: bold">return</span> cost, grad
<span style="color: #008000; font-weight: bold">def</span> <span style="color: #0000FF">train</span>(<span style="color: #008000">self</span>, trainX, trainY, testX, testY):
<span style="color: #408080; font-style: italic">#Make an internal variable for the callback function:</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>X <span style="color: #666666">=</span> trainX
<span style="color: #008000">self</span><span style="color: #666666">.</span>y <span style="color: #666666">=</span> trainY
<span style="color: #008000">self</span><span style="color: #666666">.</span>testX <span style="color: #666666">=</span> testX
<span style="color: #008000">self</span><span style="color: #666666">.</span>testY <span style="color: #666666">=</span> testY
<span style="color: #408080; font-style: italic">#Make empty list to store training costs:</span>
<span style="color: #008000">self</span><span style="color: #666666">.</span>J <span style="color: #666666">=</span> []
<span style="color: #008000">self</span><span style="color: #666666">.</span>testJ <span style="color: #666666">=</span> []
params0 <span style="color: #666666">=</span> <span style="color: #008000">self</span><span style="color: #666666">.</span>N<span style="color: #666666">.</span>getParams()
options <span style="color: #666666">=</span> {<span style="color: #BA2121">&#39;maxiter&#39;</span>: <span style="color: #666666">200</span>, <span style="color: #BA2121">&#39;disp&#39;</span> : <span style="color: #008000">True</span>}
_res <span style="color: #666666">=</span> optimize<span style="color: #666666">.</span>minimize(<span style="color: #008000">self</span><span style="color: #666666">.</span>costFunctionWrapper, params0, jac<span style="color: #666666">=</span><span style="color: #008000">True</span>, method<span style="color: #666666">=</span><span style="color: #BA2121">&#39;BFGS&#39;</span>, \
args<span style="color: #666666">=</span>(trainX, trainY), options<span style="color: #666666">=</span>options, callback<span style="color: #666666">=</span><span style="color: #008000">self</span><span style="color: #666666">.</span>callbackF)
<span style="color: #008000">self</span><span style="color: #666666">.</span>N<span style="color: #666666">.</span>setParams(_res<span style="color: #666666">.</span>x)
<span style="color: #008000">self</span><span style="color: #666666">.</span>optimizationResults <span style="color: #666666">=</span> _res
</pre></div>
<p>
<p>
<!-- navigation buttons at the bottom of the page -->
<ul class="pagination">
<li><a href="._NeuralNet-bs018.html">&laquo;</a></li>
<li><a href="._NeuralNet-bs000.html">1</a></li>
<li><a href="">...</a></li>
<li><a href="._NeuralNet-bs011.html">12</a></li>
<li><a href="._NeuralNet-bs012.html">13</a></li>
<li><a href="._NeuralNet-bs013.html">14</a></li>
<li><a href="._NeuralNet-bs014.html">15</a></li>
<li><a href="._NeuralNet-bs015.html">16</a></li>
<li><a href="._NeuralNet-bs016.html">17</a></li>
<li><a href="._NeuralNet-bs017.html">18</a></li>
<li><a href="._NeuralNet-bs018.html">19</a></li>
<li class="active"><a href="._NeuralNet-bs019.html">20</a></li>
<li><a href="._NeuralNet-bs020.html">21</a></li>
<li><a href="._NeuralNet-bs020.html">&raquo;</a></li>
</ul>
<!-- ------------------- end of main content --------------- -->
</div> <!-- end container -->
<!-- include javascript, jQuery *first* -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script src="https://netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<!-- Bootstrap footer
<footer>
<a href="http://..."><img width="250" align=right src="http://..."></a>
</footer>
-->
<center style="font-size:80%">
<!-- copyright only on the titlepage -->
</center>
</body>
</html>