using System;

namespace AForge.Math;

public class Gaussian
{
	private double sigma = 1.0;

	private double sqrSigma = 1.0;

	public double Sigma
	{
		get
		{
			return sigma;
		}
		set
		{
			sigma = System.Math.Max(1E-08, value);
			sqrSigma = sigma * sigma;
		}
	}

	public Gaussian()
	{
	}

	public Gaussian(double sigma)
	{
		Sigma = sigma;
	}

	public double Function(double x)
	{
		return System.Math.Exp(x * x / (-2.0 * sqrSigma)) / (System.Math.Sqrt(System.Math.PI * 2.0) * sigma);
	}

	public double Function2D(double x, double y)
	{
		return System.Math.Exp((x * x + y * y) / (-2.0 * sqrSigma)) / (System.Math.PI * 2.0 * sqrSigma);
	}

	public double[] Kernel(int size)
	{
		if (size % 2 == 0 || size < 3 || size > 101)
		{
			throw new ArgumentException("Wrong kernal size.");
		}
		int num = size / 2;
		double[] array = new double[size];
		int num2 = -num;
		for (int i = 0; i < size; i++)
		{
			array[i] = Function(num2);
			num2++;
		}
		return array;
	}

	public double[,] Kernel2D(int size)
	{
		if (size % 2 == 0 || size < 3 || size > 101)
		{
			throw new ArgumentException("Wrong kernal size.");
		}
		int num = size / 2;
		double[,] array = new double[size, size];
		int num2 = -num;
		for (int i = 0; i < size; i++)
		{
			int num3 = -num;
			for (int j = 0; j < size; j++)
			{
				array[i, j] = Function2D(num3, num2);
				num3++;
			}
			num2++;
		}
		return array;
	}
}