/// <summary>
/// Creates the initial clusters.
/// </summary>
private void CreateInitialClusters()
{
// compute median and std. deviation
Double[] mean = new Double[Source.Raster.NumberOfBands];
Double[] standardDeviation = new Double[Source.Raster.NumberOfBands];
for (Int32 bandIndex = 0; bandIndex < Source.Raster.NumberOfBands; bandIndex++)
{
mean[bandIndex] = 0;
standardDeviation[bandIndex] = 0;
for (Int32 rowIndex = 0; rowIndex < Source.Raster.NumberOfRows; rowIndex++)
{
for (Int32 columnIndex = 0; columnIndex < Source.Raster.NumberOfColumns; columnIndex++)
{
mean[bandIndex] += Source.Raster.GetFloatValue(rowIndex, columnIndex, bandIndex);
}
}
mean[bandIndex] /= (Source.Raster.NumberOfColumns * Source.Raster.NumberOfRows);
for (Int32 rowIndex = 0; rowIndex < Source.Raster.NumberOfRows; rowIndex++)
{
for (Int32 columnIndex = 0; columnIndex < Source.Raster.NumberOfColumns; columnIndex++)
{
standardDeviation[bandIndex] += Math.Pow(Source.Raster.GetFloatValue(rowIndex, columnIndex, bandIndex) - mean[bandIndex], 2);
}
}
standardDeviation[bandIndex] = Math.Sqrt(standardDeviation[bandIndex] / (Source.Raster.NumberOfRows * Source.Raster.NumberOfColumns - 1));
}
// generate the initial clusters
_clusterCenters = new Double[_numberOfClusters][];
GaussianRandomGenerator randomGenerator = new GaussianRandomGenerator();
for (Int32 clusterIndex = 0; clusterIndex < _numberOfClusters; clusterIndex++)
{
Double[] randomNumbers = new Double[Source.Raster.NumberOfBands];
for (Int32 bandIndex = 0; bandIndex < Source.Raster.NumberOfBands; bandIndex++)
{
randomNumbers[bandIndex] = randomGenerator.NextDouble(mean[bandIndex], standardDeviation[bandIndex]);
}
_clusterCenters[clusterIndex] = randomNumbers;
}
}
public void GaussianRandomGeneratorNextDoubleTest()
{
// numbers between 0 and 1
List <Double> generatedNumbers = Enumerable.Range(0, _numberOfGeneratedNumbers).Select(number => _generator.NextDouble()).ToList();
// range test
for (Int32 i = 0; i < _numberOfGeneratedNumbers; i++)
{
Assert.GreaterOrEqual(generatedNumbers[i], 0);
Assert.Less(generatedNumbers[i], 1);
}
// numbers with specified mean and std. variation
for (Int32 i = 0; i < _mean.Length; i++)
{
generatedNumbers = Enumerable.Range(0, _numberOfGeneratedNumbers).Select(number => _generator.NextDouble(_mean[i], _stdDeviation[i])).ToList();
// mean test
Double mean = generatedNumbers.Sum() / _numberOfGeneratedNumbers;
Assert.AreEqual(_mean[i], mean, _error[i]);
// std. deviation test
Double stdDeviation = Math.Sqrt(generatedNumbers.Sum(number => (number - mean) * (number - mean)) / _numberOfGeneratedNumbers);
Assert.AreEqual(_stdDeviation[i], stdDeviation, _error[i]);
}
}