I would like to create a bifurcation diagram with ContourPlot
. Suppose I want to plot the contour 1-2*a*Q+3*Q^3==0
with a
the x-axis, Q
the y-axis. I also want linestyle/thickness of the contour plot to change depending on the expression expr = 9*Q^2-2*a
. If expr>0
, I want it to be dashed; if expr<0
, I want it to be a thick line. How to accomplish this?
Some previous posts about similar topic suggested putting an If
statement inside the plot, but when I try something like
ContourPlot[If[expr>0, 1-2*a*Q+3*Q^3 == 0], {a,-2,2}, {Q,-2,2}]
it gives error.