/*
  Regression problem: X^4 + X^3 + X^2 + X

  Note that ** might blow up in the run:
  [program = (1 + X) * (X ** 3 + X),res = 4.0,count = 1]

  Without **:
  [program = (3 / (2 - X) + X) * (X / ((4 - X * X) / 3)),res = 4.0,count = 1]
  [program = (X + 1) * ((X * X + 1) * X),res = 4.0,count = 1]
  [program = (1 + X * X) * ((X + 1) * X),res = 4.0,count = 1]

  Using pow2/1, etc is safer than **
  [program = (X + pow3(X)) * (pow3(1) + X),res = 4.0,count = 1]
  [program = (1 + X) * (X + pow3(X)),res = 4.0,count = 1]

  pow_mod/3 and pow_mod2/2 does not work on floats.
  

  Cf regression_koza2.conf
 
*/
data(regression_koza,Data,Vars,Unknown,Ops,Constants,MaxSize,Params) :-
  Data = [
          [[-1.0],  0.0],
          [[-0.9],-0.1629],
          [[-0.8],-0.2624],
          [[-0.7],-0.3129],
          [[-0.6],-0.3264],
          [[-0.5],-0.3125],
          [[-0.4],-0.2784],
          [[-0.3],-0.2289],
          [[-0.2],-0.1664],
          [[-0.1],-0.0909],
          [[ 0.0],   0.0],
          [[ 0.1],0.1111],
          [[ 0.2],0.2496],
          [[ 0.3],0.4251],
          [[ 0.4],0.6496],
          [[ 0.5],0.9375],
          [[ 0.6],1.3056],
          [[ 0.7],1.7731],
          [[ 0.8],2.3616],
          [[ 0.9],3.0951],
          [[ 1.0],4.0000]
       ],
  Vars = ['X'],
  Unknown = [1.0],
  % Ops = [+,-,*,/,**], % might blow up in some runs
  % Ops = [+,-,*,/],
  Ops = [+,-,*,/,pow2,pow3,pow4,pow5], % This is safer than **
  Constants = 1..4,
  MaxSize = 15,
  Params = new_map([approx=0.01]).