private void regression(List <Cell> samplePoints)
{
// 构造输入输出数据集
// 样本数目
int COUNT = samplePoints.Count;
// 构造输入和输出数据集
double[][] inputs = new double[COUNT][];
bool[] outputs = new bool[COUNT];
for (int i = 0; i < COUNT; i++)
{
Cell cell = samplePoints[i];
int pos = cell.row * width + cell.col;
inputs[i] = (from buffer in driveBuffers
select buffer[pos]).ToArray <double>();
outputs[i] = cell.type;
}
var learner = new IterativeReweightedLeastSquares <Accord.Statistics.Models.Regression.LogisticRegression>()
{
Tolerance = 1e-8, // 收敛参数
Iterations = 20, // 最大循环数目
Regularization = 0,
ComputeStandardErrors = true
};
Accord.Statistics.Models.Regression.LogisticRegression regression = learner.Learn(inputs, outputs);
// 输出 odds
StringBuilder strb = new StringBuilder();
for (int i = 0; i <= inputs[0].Length; i++)
{
strb.AppendLine(" " + i + " : " + regression.GetOddsRatio(i));
}
updateConsoleEvent(strb.ToString());
// 输出 weights
StringBuilder strw = new StringBuilder();
strw.AppendLine("权重系数：");
strw.AppendLine("截距: " + regression.Intercept.ToString());
var weights = regression.Weights;
for (int i = 0; i < weights.Length; i++)
{
strw.AppendLine("权重" + (i + 1) + ":" + weights[i]);
}
updateConsoleEvent(strw.ToString());
double[] result = new double[width * height];
double minProp = double.MaxValue;
double[] minInput = null;
for (int row = 0; row < height; row++)
{
for (int col = 0; col < width; col++)
{
int pos = row * width + col;
if (beginBuffer[pos] < 0 || !IsValid(pos))
{
result[pos] = this.landUse.NullInfo.LandUseTypeValue;
continue;
}
double[] input = (from buffer in driveBuffers
select buffer[pos]).ToArray <double>();
double prop = regression.Probability(input);
if (prop < minProp)
{
minProp = prop;
minInput = input;
}
result[pos] = prop;
}
}
// 新建 GDAL dataset
OSGeo.GDAL.Driver driver = OSGeo.GDAL.Gdal.GetDriverByName("GTIFF");
OSGeo.GDAL.Dataset dataset = driver.Create(this.ResultLayerName, width, height, 1, OSGeo.GDAL.DataType.GDT_Float64, null);
dataset.WriteRaster(0, 0, width, height, result, width, height, 1, new int[1] {
1
}, 0, 0, 0);
dataset.FlushCache();
}
public double[] GetResult()
{
// 采样
List <Cell> samplePoints = getSample(this.NumberOfSample);
// 样本数目
int COUNT = samplePoints.Count;
// 构造输入和输出数据集
double[][] inputs = new double[COUNT][];
bool[] outputs = new bool[COUNT];
for (int i = 0; i < COUNT; i++)
{
Cell cell = samplePoints[i];
int pos = cell.row * width + cell.col;
inputs[i] = (from buffer in driveBuffers
select buffer[pos]).ToArray <double>();
outputs[i] = cell.type;
}
var learner = new IterativeReweightedLeastSquares <Accord.Statistics.Models.Regression.LogisticRegression>()
{
Tolerance = 1e-8, // 收敛参数
Iterations = 20, // 最大循环数目
Regularization = 0,
ComputeStandardErrors = true
};
Accord.Statistics.Models.Regression.LogisticRegression regression = learner.Learn(inputs, outputs);
//// 输出 odds
//StringBuilder strb = new StringBuilder();
//for (int i = 0; i <= inputs[0].Length; i++)
//{
// strb.AppendLine(" " + i + " : " + regression.GetOddsRatio(i));
//}
//updateConsoleEvent(strb.ToString());
//// 输出 weights
//StringBuilder strw = new StringBuilder();
//strw.AppendLine("权重系数：");
//strw.AppendLine("截距: " + regression.Intercept.ToString());
//var weights = regression.Weights;
//for (int i = 0; i < weights.Length; i++)
//{
// strw.AppendLine("权重" + (i + 1) + ":" + weights[i]);
//}
//updateConsoleEvent(strw.ToString());
double[] result = new double[width * height];
double minProp = double.MaxValue;
double[] minInput = null;
for (int row = 0; row < height; row++)
{
for (int col = 0; col < width; col++)
{
int pos = row * width + col;
if (beginBuffer[pos] < 0 || !IsValid(pos))
{
result[pos] = this.landUse.NullInfo.LandUseTypeValue;
continue;
}
double[] input = (from buffer in driveBuffers
select buffer[pos]).ToArray <double>();
double prop = regression.Probability(input);
if (prop < minProp)
{
minProp = prop;
minInput = input;
}
result[pos] = prop;
}
}
return(result);
}