.Spot.Base.Math.polyCoef

Information

The function determines the coefficients c of a polynomial of degree n from its root vector r.

  c_0 + c_1*x + c_2*x^2 + ... + c_n*x^n.

The resulting n+1 coefficients are c[k, :], k=1 .. n+1, normalised such that the highest coefficient is one.

  c[n+1, :] = {1, 0}
  c[k, 1]: real part
  c[k, 2]: imaginary part

Example

  Real[3,2] r=[1,0;2,0;3,0];
  Real[4,2] c;
algorithm
  c := Spot.Functions.polyCoef(r);

The resulting n+1 = 4 coefficients are:

  c = [-6, 0; 11, 0; -6, 0; 1, 0];

See also polyCoefReal, polyRoots

Interface

function polyCoef
  extends Icons.Function;
  input Real[:, 2] r "root vector, 2nd index=1:2, real and imaginary part";
  output Real[size(r, 1) + 1, 2] c "coefficient vector, 2nd index=1:2, real and imaginary part";
end polyCoef;