Inline AnyScript implementation of a smooth step function with zero 1st and 2nd derivative at the edges.

smootherstep.any

/*
// Inline AnyScript implementation of the following C++ function: 
// https://en.wikipedia.org/wiki/Smoothstep
float smootherstep(float edge0, float edge1, float x)
{
    // Scale, and clamp x to 0..1 range
    x = clamp((x - edge0)/(edge1 - edge0), 0.0, 1.0);
    // Evaluate polynomial
    return x*x*x*(x*(x*6 - 15) + 10);
}

Usage:
Include the file in your model. 
#include "smootherstep.any"

*/

// 1st and 2nd order derivatives at edge0 and edge1 are 0
#define smootherstep(edge0, edge1, val) mult(iffun(ltfun((val-edge0)/(edge1-edge0),0.0), 0*val, iffun(gtfun((val-edge0)/(edge1-edge0),1.0),0*val+1.0, (val-edge0)/(edge1-edge0)))\
                                       ,mult(iffun(ltfun((val-edge0)/(edge1-edge0),0.0), 0*val, iffun(gtfun((val-edge0)/(edge1-edge0),1.0),0*val+1.0, (val-edge0)/(edge1-edge0)))\
                                       ,mult(iffun(ltfun((val-edge0)/(edge1-edge0),0.0), 0*val, iffun(gtfun((val-edge0)/(edge1-edge0),1.0),0*val+1.0, (val-edge0)/(edge1-edge0)))\
                                       ,(mult(iffun(ltfun((val-edge0)/(edge1-edge0),0.0), 0*val, iffun(gtfun((val-edge0)/(edge1-edge0),1.0),0*val+1.0, (val-edge0)/(edge1-edge0)))\
                                       ,(iffun(ltfun((val-edge0)/(edge1-edge0),0.0), 0*val, iffun(gtfun((val-edge0)/(edge1-edge0),1.0),0*val+1.0, (val-edge0)/(edge1-edge0)))\
                                        *6 - 15)) + 10)  )))


                                         
#if ANYBODY_FILENAME_MAINFILE == "smootherstep.any"
//  Test code. Only active if the file is loaded as main
Main = 
{
  // Run the function on a vector input
  AnyVector x_test = farr(-1.0, 0.1, 100);
  AnyVector y_test = smootherstep(0, 3, x_test);
  
   AnyBodyStudy test_study = 
   {
     Gravity = {0,0,0};
     // Run the function on single values as part of a study.
     AnyVar test_curve = smootherstep(0.3, 0.8, t);
   };
};
#endif