code: private double handleCase4() {
  		if( bracket ) {
  			return SearchInterpolate.cubic2(fp, gp, stp, fy, gy, sty);
  		} else if( stp > stx ) {
  			return stmax;  // see comment in case 3 about stmax and stmin
  		} else {
  			return stmin;
  		}
  	}
docs: Lower function value. On the same side of the dip because the gradients have the same sign. The magnitude
  of the derivative did not decrease.
  
  @return The new step.