code: protected void cauchyStep(double regionRadius, DMatrixRMaj step) {
  
  		CommonOps_DDRM.scale(-regionRadius, direction, step);
  		stepLength = regionRadius; // it touches the trust region
  		predictedReduction = regionRadius*(owner.gradientNorm - 0.5*regionRadius*gBg);
  	}
docs: Computes the Cauchy step, This is only called if the Cauchy point lies after or on the trust region
  @param regionRadius (Input) Trust region size
  @param step (Output) The step