code: public LineSearchMore94 setConvergence(double ftol, double gtol, double xtol) {
  		if( ftol < 0 )
  			throw new IllegalArgumentException("ftol must be >= 0 ");
  		if( gtol < 0 )
  			throw new IllegalArgumentException("gtol must be >= 0 ");
  		if( xtol < 0 )
  			throw new IllegalArgumentException("xtol must be >= 0 ");
  
  		this.ftol = ftol;
  		this.gtol = gtol;
  		this.xtol = xtol;
  		return this;
  	}
docs: Configures the line search.
  
  @param ftol Tolerance for sufficient decrease. ftol {@code >} 0. Smaller value for loose tolerance.  Try 1e-4
  @param gtol Tolerance for curvature condition. gtol &ge; 0. Larger value for loose tolerance.  Try 0.9
  @param xtol Relative tolerance for acceptable step. xtol &ge; 0. Larger value for loose tolerance.  Try 1e-4.
  
  @return Reference to this class to allow for command chaining.