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87 lines
3.0 KiB
87 lines
3.0 KiB
// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
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/*
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This is an example illustrating the use of the multilayer perceptron
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from the dlib C++ Library.
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This example creates a simple set of data to train on and shows
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you how to train a mlp object on that data.
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The data used in this example will be 2 dimensional data and will
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come from a distribution where points with a distance less than 10
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from the origin are labeled 1 and all other points are labeled
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as 0.
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*/
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#include <iostream>
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#include <dlib/mlp.h>
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using namespace std;
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using namespace dlib;
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int main()
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{
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// The mlp takes column vectors as input and gives column vectors as output. The dlib::matrix
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// object is used to represent the column vectors. So the first thing we do here is declare
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// a convenient typedef for the matrix object we will be using.
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// This typedef declares a matrix with 2 rows and 1 column. It will be the
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// object that contains each of our 2 dimensional samples. (Note that if you wanted
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// more than 2 features in this vector you can simply change the 2 to something else)
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typedef matrix<double, 2, 1> sample_type;
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// make an instance of a sample matrix so we can use it below
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sample_type sample;
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// Create a multi-layer perceptron network. This network has 2 nodes on the input layer
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// (which means it takes column vectors of length 2 as input) and 5 nodes in the first
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// hidden layer. Note that the other 4 variables in the mlp's constructor are left at
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// their default values.
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mlp::kernel_1a_c net(2,5);
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// Now let's put some data into our sample and train on it. We do this
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// by looping over 41*41 points and labeling them according to their
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// distance from the origin.
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for (int i = 0; i < 1000; ++i)
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{
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for (int r = -20; r <= 20; ++r)
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{
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for (int c = -20; c <= 20; ++c)
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{
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sample(0) = r;
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sample(1) = c;
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// if this point is less than 10 from the origin
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if (sqrt((double)r*r + c*c) <= 10)
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net.train(sample,1);
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else
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net.train(sample,0);
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}
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}
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}
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// Now we have trained our mlp. Let's see how well it did.
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// Note that if you run this program multiple times you will get different results. This
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// is because the mlp network is randomly initialized.
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// each of these statements prints out the output of the network given a particular sample.
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sample(0) = 3.123;
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sample(1) = 4;
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cout << "This sample should be close to 1 and it is classified as a " << net(sample) << endl;
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sample(0) = 13.123;
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sample(1) = 9.3545;
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cout << "This sample should be close to 0 and it is classified as a " << net(sample) << endl;
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sample(0) = 13.123;
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sample(1) = 0;
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cout << "This sample should be close to 0 and it is classified as a " << net(sample) << endl;
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}
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