.TRANSFORM.Math.regStep

Information

This function is used to approximate the equation

    y = if x > 0 then y1 else y2;

by a smooth characteristic, so that the expression is continuous and differentiable:

   y = smooth(1, if x >  x_small then y1 else
                 if x < -x_small then y2 else f(y1, y2));

In the region -x_small < x < x_small a 2nd order polynomial is used for a smooth transition from y1 to y2.

Interface

function regStep
  extends TRANSFORM.Icons.Function;
  input Real pos "Ordinate value for x > 0";
  input Real neg "Ordinate value for x < 0";
  input Real x "Abscissa value";
  input Real deltax(min = 0) = 1e-5 "Approximation of step for -deltax <= x <= deltax; deltax >= 0 required";
  output Real y "Ordinate value to approximate y = if x > 0 then y1 else y2";
end regStep;