Skip to main content

differential equations - Plotting a Bifurcation diagram


I have the following system equation


v'(t)=2*G*J1[v(t-τ)]cos(w*τ)-v(t)

How do you plot the bifurcation diagram, τ in the x axis, Vmax in the y axis? I have written these lines but how can one plot using the following



Table[NDSolve[{v'[t] == 
2*G*BesselJ[1, v[t - τ + i]]*Cos[ω*(τ + i)] -
v[t], v[0] == 0.001}, v, {t, 0, 500}], {i, 0, 4, 0.01}]

τ is varied from 1 to 4 using step 0.01,G=3.55, ω=2*Pi*12*10^6



Answer



An alternative representation is


G = 3.55; ω = 2*Pi*12*10^6;
s = ParametricNDSolveValue[{v'[t] == 2*G*BesselJ[1, v[t - τ]] Cos[ω*τ] - v[t],
v[t /; t <= 0] == 0.001}, {v, v'}, {t, 0, 120}, {τ}];

Manipulate[ParametricPlot[{s[τ][[1]][t], s[τ][[2]][t]}, {t, 60, 120},
AxesLabel -> {v, v'}, AspectRatio -> 1], {{τ, 2}, 1, 4}]

enter image description here


Note that the diagram becomes progressively more complex as τ is increased, and the run time increases correspondingly.


Addendum


The bifurcations can be seen even more clearly from a return map, for instance,


tab = Table[{sol, points} = Reap@NDSolveValue[{v'[t] == 
2*G*BesselJ[1, v[t - τ]] Cos[ω*τ] - v[t], v[t /; t <= 0] == 0.001,
WhenEvent[v'[t] > 0, If[t > 150, Sow[v[t]]]]}, {v, v'}, {t, 0, 250}];

{τ, #} & /@ Union[Flatten[points], SameTest -> (Abs[#1 - #2] < .05 &)],
{τ, 1.7, 2.4, .01}];
ListPlot[Flatten[tab, 1]]

enter image description here


where v is sampled whenever v' passes from positive to negative values. A blow-up of the map near the transition to chaos is (with SameTest deleted)


enter image description here


It is anyone's guess precisely where the transition to chaos occurs. Perhaps, very near τ = 2.32.


enter image description here


Additional Material in Response to Comments



Recent comments by udichi, the OP, and by Chris K prompted me to consider this problem further. Stability windows typically occur within the chaotic region, udichi now wanted to see them. A straightforward three-hour computation produced interesting results, but no windows. (Note that WorkingPrecision -> 30 is used to reduce the chance that numerical inaccuracies might corrupt the results.)


tab = ParallelTable[{sol, points} = 
Reap@NDSolveValue[{v'[t] == 2*G*BesselJ[1, v[t - τ]] Cos[ω*τ] - v[t],
v[t /; t <= 0] == 10^-3, WhenEvent[v'[t] > 0, If[t > 500, Sow[v[t]]]]}, {v, v'},
{t, 0, 1000}, WorkingPrecision -> 30, MaxSteps -> 10^6]; {τ, #} & /@
Union[Flatten[points]], {τ, 1, 15, 1/100}];
ListPlot[Flatten[tab, 1], AspectRatio -> .75/GoldenRatio,
ImageSize -> Full, PlotStyle -> PointSize[Tiny]]

enter image description here



Here are diagrams for interesting values of τ. Typical plots for τ > 8 are


f[τ_] := Module[{}, 
ss = NDSolveValue[{v'[t] == 2*G*BesselJ[1, v[t - τ]] Cos[ω*τ] - v[t],
v[t /; t <= 0] == 10^-3}, {v, v'}, {t, 0, 1000},
WorkingPrecision -> 30, MaxSteps -> 10^6];
GraphicsRow[{ParametricPlot[Through[ss[t]], {t, 500, 1000},
AxesLabel -> {v[t], v'[t]}, AspectRatio -> 1, PlotPoints -> 200],
ParametricPlot[First[ss][#] & /@ {t, t - τ}, {t, 500, 1000},
AxesLabel -> {v[t], v[t - τ]}, AspectRatio -> 1, PlotPoints -> 200]},
ImageSize -> Large]]


f[15]

enter image description here


The left plot depicts v' vs. v, similar to some of the earlier plots although much more chaotic. The solution appears to move randomly between two chaotic attractors. The right plot depicts v[t - τ] vs. v[t], as suggested here. The advantage of this alternative representation will soon become evident. Typical plots from the transition region, centered around τ == 7, are


f[15/2]

enter image description here


while typical plots from smaller but chaotic values of τ look much different.


f[3]


enter image description here


Finally, plots for τ = 2.285, the approximate onset of chaos (as determined by Chris K) are


enter image description here


Plots for τ as large as 2.4 are qualitively similar, although obviously chaotic. This suggests computing a return map based on v[t - τ] == 2.5.


tab = ParallelTable[{sol, points} = 
Reap@NDSolveValue[{v'[t] == 2*G*BesselJ[1, v[t - τ]] - v[t],
v[0] == 10^-3, tem[0] == 1500, WhenEvent[v[t] > 5/2, tem[t] -> t],
WhenEvent[t > tem[t] + τ, If[t > 1500, Sow[v[t]]]]}, {v[t], tem[t]}, {t, 0, 2200},
DiscreteVariables -> {tem}, WorkingPrecision -> 30, MaxSteps -> 10^6];

{τ, #} & /@ Flatten[points], {τ, 225/100, 240/100, 1/2000}];
ListPlot[Flatten[tab, 1], AspectRatio -> .75/GoldenRatio, ImageSize -> Full,
PlotStyle -> PointSize[Tiny]]

enter image description here


It shows the transition to chaos (at about τ = 2.286) as well as the first three windows of stability within the region of chaos. Note that a comparatively long run-time in t is necessary to allow solutions near bifurcation points to reach asymptotic states. High resolution in τ is, of course, also needed. Incidentally, this last computation throws the warning message described in the second section of question 157889, but it can be ignored.


Plots in Windows of Stability


As suggested by Chris K, it may be useful to provide plots in the three windows of stability shown in the last figure.


f[2303/1000]


enter image description here


f[2330/1000]

enter image description here


f[2348/1000]

enter image description here


These plots differ strikingly from their chaotic neighbors, say τ == 3, above.


Comments

Popular posts from this blog

plotting - Plot 4D data with color as 4th dimension

I have a list of 4D data (x position, y position, amplitude, wavelength). I want to plot x, y, and amplitude on a 3D plot and have the color of the points correspond to the wavelength. I have seen many examples using functions to define color but my wavelength cannot be expressed by an analytic function. Is there a simple way to do this? Answer Here a another possible way to visualize 4D data: data = Flatten[Table[{x, y, x^2 + y^2, Sin[x - y]}, {x, -Pi, Pi,Pi/10}, {y,-Pi,Pi, Pi/10}], 1]; You can use the function Point along with VertexColors . Now the points are places using the first three elements and the color is determined by the fourth. In this case I used Hue, but you can use whatever you prefer. Graphics3D[ Point[data[[All, 1 ;; 3]], VertexColors -> Hue /@ data[[All, 4]]], Axes -> True, BoxRatios -> {1, 1, 1/GoldenRatio}]

plotting - Filling between two spheres in SphericalPlot3D

Manipulate[ SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, Mesh -> None, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], {n, 0, 1}] I cant' seem to be able to make a filling between two spheres. I've already tried the obvious Filling -> {1 -> {2}} but Mathematica doesn't seem to like that option. Is there any easy way around this or ... Answer There is no built-in filling in SphericalPlot3D . One option is to use ParametricPlot3D to draw the surfaces between the two shells: Manipulate[ Show[SphericalPlot3D[{1, 2 - n}, {θ, 0, Pi}, {ϕ, 0, 1.5 Pi}, PlotPoints -> 15, PlotRange -> {-2.2, 2.2}], ParametricPlot3D[{ r {Sin[t] Cos[1.5 Pi], Sin[t] Sin[1.5 Pi], Cos[t]}, r {Sin[t] Cos[0 Pi], Sin[t] Sin[0 Pi], Cos[t]}}, {r, 1, 2 - n}, {t, 0, Pi}, PlotStyle -> Yellow, Mesh -> {2, 15}]], {n, 0, 1}]

plotting - Mathematica: 3D plot based on combined 2D graphs

I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these different 2D plots projected in 3D as in but then using proper perspective. In the link here they give some solutions to combine the plots using isometric perspective, but I would like to use proper 3 point perspective. Any thoughts? Also any way to show the mean points per time point for each series plus or minus the standard error on the mean would be cool too, either using points+vertical bars, or using spheres plus tubes. Below are some test data and the fit function I am using. Note that I am working on a logit(proportion) scale and that the final vertical scale is Log10(percentage). (* some test data *) data = Table[Null, {i, 4}]; data[[1]] = {{1, -5.8}, {2, -5.4}, {3, -0.8}, {4, -0.2}, {5, 4.6}, {1, -6.4}, {2, -5.6}, {3, -0.7}, {4, 0.04}, {5, 1.0}, {1, -6.8}, {2, -4.7}, {3, -1....