Dear all,

I recently encountered a problem when finding the posterior mode. I hope anyone who experienced similar situations could give me some hints or suggestions. The plot has been attached.

Usually, the mode_check plot after finding the mode looks like a smooth concave curve as the middle one in the attached plot. But I also got some cases like the left one and the right one, in which the curve is not a concave one. The highest point is the intersection of two convex curves. I did a very comprehensive search for the mode and always got this result. I am wondering if this situation is normal?

Thanks in advance!

MyCheckPlot.rar (3.62 KB)