Mathematica中ContourPlot的缺省绘制往往达不到要求，这就需要对其各个绘制参数进行设置，这里通过对Contours，ContourShading，ColorFunction等参数进行调整，基本达到了绘制要求。图中绘制的是参考[1]中的JCM也就是CMA(Constant Modulus Algorithm)的Cost Function(Objective function, energy function[2])。类似的图在文献[3,4]中也可以找到。

[1]R. Johnson Jr, P. Schniter, T. Endres et al., "Blind equalization using the constant modulus criterion: a review," Proceedings of the IEEE, 1998, vol. 86, no. 10:  pp. 1927-1950.
[2]D. Wolpert, W. Macready, I. Center et al., "No free lunch theorems for optimization," Evolutionary Computation, IEEE Transactions on, 1997, vol. 1, no. 1:  pp. 67-82.
[3]S. S. Haykin, Adaptive filter theory, 4th ed., Upper Saddle River, N.J.: Prentice Hall, 2002.
[4]P. S. R. Diniz, Adaptive filtering : algorithms and practical implementation, 3rd ed., New York: Springer, 2008.