/// <summary>
///
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <param name="power"></param>
/// <param name="cf"></param>
/// <param name="error"></param>
/// <param name="equation"></param>
/// <returns></returns>
private static Complex32[] powr(Complex32[] x, Complex32[] y, int power, out Complex32[] cf, out Complex32 error, out string equation)
{
// Options:
int m = (power < 1) ? 2 : power + 1;
int n = x.Length, i;
Complex32[] xa = new Complex32[n];
Complex32[] ya = new Complex32[n];
// log-scale:
for (i = 0; i < n; i++)
{
xa[i] = Maths.Log(x[i]);
ya[i] = Maths.Log(y[i]);
}
// approximation:
cf = LeastSquaresOptions.Coefficients(xa, ya, m);
Complex32[] p = LeastSquaresOptions.Polynomial(xa, cf);
// exponential-scale:
for (i = 0; i < n; i++)
{
ya[i] = Maths.Exp(p[i]);
}
error = LeastSquaresOptions.Error(ya, y);
equation = "EXP" + '(' + LeastSquaresOptions.Equation(cf, " * LN(X)^") + ')';
return(ya);
}
/// <summary>
///
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <param name="power"></param>
/// <param name="cf"></param>
/// <param name="error"></param>
/// <param name="equation"></param>
/// <returns></returns>
private static float[] expn(float[] x, float[] y, int power, out float[] cf, out float error, out string equation)
{
// Options:
int m = (power < 1) ? 2 : power + 1;
int n = x.Length, i;
float[] ya = new float[n];
// log-scale:
for (i = 0; i < n; i++)
{
ya[i] = Maths.Log(y[i], Maths.E);
}
// approximation:
cf = LeastSquaresOptions.Coefficients(x, ya, m);
float[] p = LeastSquaresOptions.Polynomial(x, cf);
// exponential-scale:
for (i = 0; i < n; i++)
{
ya[i] = Maths.Pow(Maths.E, p[i]);
}
error = LeastSquaresOptions.Error(ya, y);
equation = "EXP" + '(' + LeastSquaresOptions.Equation(cf) + ')';
return(ya);
}
/// <summary>
///
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <param name="power"></param>
/// <param name="cf"></param>
/// <param name="error"></param>
/// <param name="equation"></param>
/// <returns></returns>
private static Complex32[] poly(Complex32[] x, Complex32[] y, int power, out Complex32[] cf, out Complex32 error, out string equation)
{
// Options:
int m = (power < 1) ? 2 : power + 1;
cf = LeastSquaresOptions.Coefficients(x, y, m);
Complex32[] ya = LeastSquaresOptions.Polynomial(x, cf);
error = LeastSquaresOptions.Error(ya, y);
equation = LeastSquaresOptions.Equation(cf);
return(ya);
}
/// <summary>
///
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <param name="power"></param>
/// <param name="cf"></param>
/// <param name="error"></param>
/// <param name="equation"></param>
/// <returns></returns>
private static Complex32[] logc(Complex32[] x, Complex32[] y, int power, out Complex32[] cf, out Complex32 error, out string equation)
{
// Options:
int n = x.Length, i;
int m = (power < 1) ? 2 : power + 1;
Complex32[] xa = new Complex32[n];
Complex32[] ya = new Complex32[n];
// log-scale:
for (i = 0; i < n; i++)
{
xa[i] = Maths.Log(x[i]);
}
// approximation:
cf = LeastSquaresOptions.Coefficients(xa, y, m);
ya = LeastSquaresOptions.Polynomial(xa, cf);
error = LeastSquaresOptions.Error(ya, y);
equation = LeastSquaresOptions.Equation(cf, " * LN(X)^");
return(ya);
}
