Modelica function that calculates intersection of two polynomials using Modelica.Math.Vectors.Utilities.roots

polyIntersect.mo

function polyIntersect
  input Real[:] poly1={3,2,1,0};
  input Real[:] poly2={8,7};
  output Real[:,2] intersect;

protected 
  Integer nPoly1 = size(poly1,1);
  Integer nPoly2 = size(poly2,1);
  Integer nPolyShort = min(nPoly1, nPoly2);
  Integer nPolyLong = max(nPoly1, nPoly2);
  Real[nPolyShort] polyShort;
  Real[nPolyLong] polyLong;
  Real[nPolyLong] polyDiff;

algorithm 
  if (nPoly1<nPoly2) then 
    polyShort := poly1;
    polyLong := poly2;
  else 
    polyShort := poly2;
    polyLong := poly1;
  end if;
  
  polyDiff := polyLong;
  for i in 0:nPolyShort-1 loop
    polyDiff[nPolyLong-i] := polyLong[nPolyLong-i] - polyShort[nPolyShort-i];
  end for;
  
  intersect := Modelica.Math.Vectors.Utilities.roots(polyDiff);
  
end polyIntersect;