Activity for MatCont

hilmeijer posted a comment on discussion Help

hilmeijer — Tue, 21 Apr 2026 07:55:54 -0000

This is not necessarily a well-posed question; you can use MatCont for "standard" dynamical systems analysis, so why would the methods differ from any other tool? So it is the Real Part of Eigenvalues for equilibria, or the modulus of Floquet Multipliers for limit cycles. You can inspect the stability looking at a Numeric Window, The Data Browser, or change plot properties (EQ/LC if unstable 'Color','red').

CHI posted a comment on discussion Help

CHI — Tue, 21 Apr 2026 03:04:41 -0000

What method should be used in MATCONT to distinguish between stable and unstable solutions?

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Thu, 16 Apr 2026 16:27:16 -0000

Sorry, but we cannot check just any equations. But suppose these are correct. What you also need is a good initial point. If you start too far away from an equilibrium it will not be able to find it, that is the newton iterations will not converge. So you may first do a simulation (like in the first tutorial) to observe the behaviour and get an idea of what the system is doing.

Ram singh posted a comment on discussion Open Discussion

Ram singh — Thu, 16 Apr 2026 09:34:23 -0000

Please see where is mistak. it show no convergence at X0.

Mazilu Traian posted a comment on discussion Open Discussion

Mazilu Traian — Tue, 14 Apr 2026 22:15:19 -0000

Thank you for your response.

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Sun, 12 Apr 2026 14:52:58 -0000

While I understand how you want to enter your system, the GUI does not work this way. The problem is that we chose to work with scalar state variables. Not with vector-valued ones. In our recent work to work with delays we sort of have an option for vector-valued variables but it is far from automated. Work in progress, if anyone has time. For now, what you can do, is to create a simple system with the correct number of state variables and parameters but no irrelevant ODEs. After creating the file,...

hilmeijer posted a comment on discussion Help

hilmeijer — Sun, 12 Apr 2026 11:12:33 -0000

In versions 7p5 and 7p6, we have disabled this menu item for this switch as it is not there, indeed. In the version for maps (MatContM) we have implemented the switch GPD to LPC of double period, but we never created the file for the continuous-time case. If you want to proceed, you better start a bit away from the GPD point and switch to the doubled cycle from a regular point on the PD curve to detect the LPC point from regular one-parameter continuation. You may have to try starting from both sides...

cheng posted a comment on discussion Help

cheng — Sun, 12 Apr 2026 10:28:25 -0000

Hi, I am working on MatCont7p4, GUI version. I have obtained the PD locus and detected several GPD on it. Now I want to switch the branch from GPD to obtain the LPC locus of double period. However, when I trying to do that, error appeared noting: Undefined function 'init_GPD_LPC' for input arguments of type 'FacadeMatrix'. I am wondering what is the possible reason for that? I have also check the MatCont ManualAug2019, in section 8.4.3, there is no mention on the initializer from GPD to LPC. Is that...

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Fri, 10 Apr 2026 14:03:32 -0000

No clue, I do not manage to reproduce this error, so cannot help.

Ram singh posted a comment on discussion Open Discussion

Ram singh — Fri, 10 Apr 2026 12:30:43 -0000

I manuallly typed model in Matcont>System, itis uplaoded and show in system window but when i run the model it show following lines Error using feval Undefined function 'file_Callback' for input arguments of type 'matlab.ui.control.UIControl'. Error in dengue_matcont" to a folder where you have placed the matcont files.

Ram singh posted a comment on discussion Open Discussion

Ram singh — Wed, 08 Apr 2026 13:16:32 -0000

while mannually typing model , the sytem show permission denied and not uploading model. please tell me where is problem.

Ram singh posted a comment on discussion Open Discussion

Ram singh — Wed, 08 Apr 2026 13:15:45 -0000

while mannually typing model , the sysytem show permission denied

hilmeijer posted a comment on discussion Help

hilmeijer — Wed, 18 Mar 2026 13:35:43 -0000

Have a look at the manual; Chapter 4 on the structure of the ODEFILE, and how to add it in the GUI.

zhaoyujie posted a comment on discussion Help

zhaoyujie — Mon, 16 Mar 2026 09:45:06 -0000

zhaoyujie posted a comment on discussion Help

zhaoyujie — Mon, 16 Mar 2026 09:44:44 -0000

Thank you for your response. The problem has been solved. Now, there is still one question I would like to ask you. I have already created my own user function. How should I call it in the MatCont GUI?

hilmeijer posted a comment on discussion Help

hilmeijer — Fri, 13 Mar 2026 08:41:21 -0000

EEG is not a variable, but an expression, so remove that from the coordinates, and put it before the differential equations, not after. If you need the value of "EEG" then add it as a user function, or compute it afterwards.

zhaoyujie posted a comment on discussion Help

zhaoyujie — Fri, 13 Mar 2026 08:38:36 -0000

How should I make the necessary adjustments so that the model can be imported into the system?

zhaoyujie posted a comment on discussion Help

zhaoyujie — Fri, 13 Mar 2026 08:36:36 -0000

zhaoyujie posted a comment on discussion Help

zhaoyujie — Fri, 13 Mar 2026 08:33:44 -0000

Could you please tell me how to solve the problem of the coordinates on the left not matching when I add the model?

hilmeijer posted a comment on discussion Help

hilmeijer — Wed, 11 Mar 2026 11:23:46 -0000

The expressions (ZP to vf) should come before the differential equations. It is code, if you compute those intermediate quantities after you use them, who could tell what value they should have.

zhaoyujie posted a comment on discussion Help

zhaoyujie — Wed, 11 Mar 2026 11:19:02 -0000

zhaoyujie posted a comment on discussion Help

zhaoyujie — Wed, 11 Mar 2026 11:17:16 -0000

zhaoyujie posted a comment on discussion Help

zhaoyujie — Wed, 11 Mar 2026 11:12:32 -0000

Could you please tell me how to solve the problem when my program keeps giving errors?

Mazilu Traian modified a comment on discussion Open Discussion

Mazilu Traian — Sun, 08 Mar 2026 16:49:34 -0000

Hello, 10D mechanical system (5 coordinates+5 velocitie): Coordinates: x1, x2, x3, x4, x5, vx1, vx2, vx3, vx4, vx5 State-space form: M = 5x5 mass matrix; K = 5x5 stiffness matrix; C = 5x5 damping matrix; F = 5x1 nonlinear forces; A = [0(5×5) I(5×5); -M^(-1)K -M^(-1)C] B = [0(5×5); M^(-1)] dy = Ay + BF Issues: GUI editor auto-splits the lines "Equations don't match coordinates" error No Starter/Activator windows after load Questions: Matrix form supported directly in ODE field (dy=Ay+BF)? If yes,...

Mazilu Traian posted a comment on discussion Open Discussion

Mazilu Traian — Sun, 08 Mar 2026 16:30:58 -0000

Hello, 10D mechanical system (5 coordinates+5 velocitie): Coordinates: x1, x2, x3, x4, x5, vx1, vx2, vx3, vx4, vx5 State-space form: M = 5x5 mass matrix; K = 5x5 stiffness matrix; C = 5x5 damping matrix; F = 5x1 nonlinear forces; A = [0(5×5) I(5×5); -M^(-1)K -M^(-1)C] B = [0(5×5); M^(-1)] dy = Ay + BF Issues: GUI editor auto-splits the lines "Equations don't match coordinates" error No Starter/Activator windows after load Quetions: Matrix form supported directly in ODE field (dy=Ay+BF)? If yes, the...

hilmeijer posted a comment on discussion Help

hilmeijer — Thu, 26 Feb 2026 09:57:09 -0000

Dear Ram, The Graphical User Interface looks for a file "model.mat" with a particular structure including equations. These equations are then converted into a "model.m" file. If you supply only the ".m-file" then the interface does not know about it. However, you could still use MatCont in command-line mode as during the simulations and continuation that m-file is the necessary ingredient. Best regards, Hil

Ram singh posted a comment on discussion Help

Ram singh — Sun, 22 Feb 2026 07:34:05 -0000

I have prepared a model.m file in Matlab and copied in MATCONT /system/ model.m in directory and when I asked matcont to lead my model it doesn’t it show. It shows only in-built models. Then I have to type manually in System window of Matcont and loaded it. Why matcont doesn’t take it directly With warm Regards Dr. Ram Singh, Assistant Professor * Department of Mathematical Sciences BGSB University, Rajouri-185131 (J&K-India)* On Tue, Jan 20, 2026 at 8:28 PM hilmeijer hilmeijer@users.sourceforge.net...

MatCont updated /MatCont/MatCont7p6/MatCont7p6.zip

MatCont — Thu, 12 Feb 2026 21:29:05 -0000

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Wed, 11 Feb 2026 10:09:50 -0000

It's clear some people simply need and want this, even though from a plotting point of view it is slightly ambiguous as it concerns just a single value for the state (and max=min). This can be achieved through the following change: In file GUI\CLContOutputInterpreter.m Add the following lines 120,121 plotsel.declareItem('coordinates', coordinates{index}, 'Max', sprintf('max(%s)', coordinates{index}), @(x, h, f, s, ind, i)x(index, ind)); plotsel.declareItem('coordinates', coordinates{index}, 'Min',...

MatCont updated /MatCont/MatCont7p6/MatCont7p6.zip

MatCont — Sun, 08 Feb 2026 23:37:04 -0000

MatCont updated /MatCont/MatCont7p6/MatCont7p6.zip

MatCont — Sun, 08 Feb 2026 23:07:04 -0000

MatCont released /Documentation/MatContODE/AdvancedTutorials/MatCont_Tutorial_Delay.pdf

MatCont — Wed, 04 Feb 2026 11:43:04 -0000

Alois Steindl posted a comment on discussion Open Discussion

Alois Steindl — Wed, 21 Jan 2026 15:58:15 -0000

Dear Hil and colleagues, I observe a new phenomenon, which I didn't encounter earlier: I want to draw a bifurcation diagram with steady solutions and periodic orbits. As soon as I select to draw the maximum value of a state variable along a periodic branch, the stationary solutions vanish from the figure and I obtain messages like plotDiagram: solution rejected, invalid layout (LP_LP(1).mat). If you need some test data, I could provide these. With kind wishes Alois

hilmeijer posted a comment on discussion Help

hilmeijer — Tue, 20 Jan 2026 14:58:24 -0000

The error suggests you use the symbol x in your code but you do not give it a value. However, without the model specification we cannot be sure. Good luck debugging.

Ram singh posted a comment on discussion Help

Ram singh — Tue, 20 Jan 2026 14:17:35 -0000

While try to run the model for bifurcation, the error is shown as attachment , please help me why is showing undefined function 'x' for input argument of type double

Alois Steindl posted a comment on discussion Open Discussion

Alois Steindl — Thu, 15 Jan 2026 21:12:22 -0000

Dear Hil and colleagues, with an example, that I wanted to present in the lecture, I observe a bad error in MatCont 7.6: For a triple pendulum with follower force loading and a supporting spring I follow a branch of Hopf points in the parameter plane and encounter also ZH points. Quite regularly I obtain the error message, that an unexpeted error occured caused by missing/wrong indices. The same problem occurs also, when I follow the zero eigenvalue and encounter the ZH point. The reason for this...

hilmeijer posted a comment on discussion Help

hilmeijer — Sat, 10 Jan 2026 13:05:20 -0000

The tutorial also shows what to plot, and the documentation explains what these continuation variables mean.

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Sat, 10 Jan 2026 13:02:37 -0000

Hmm... As the tutorials were fine for you, nothing seems strange. But without details to reproduce this error, it's too hard to see what's happening.

Vadim Karatayev posted a comment on discussion Open Discussion

Vadim Karatayev — Fri, 09 Jan 2026 23:37:18 -0000

Hi, I'm getting a wacky error making a bifurcation to nearly the normal form of the saddle-node bfn. Any insights on whether I'm doing something wrong or if its a faulty installation? Previously I went through the tutorial for the lorenz system and recreated the bifurcation in the manual without any issues. PS: I'm new to this fine app, and also to MATLAB. Thank you!!

Xuan Li posted a comment on discussion Help

Xuan Li — Fri, 09 Jan 2026 16:44:23 -0000

Thank you for your sharing. While I viewed mat-file in Systems/diagram/ (figure 1), which Tables correspond to the x and y-axis data of the frequency response curve? What do these data represent, such as "f", "h" and "x" (figure 2).

hilmeijer posted a comment on discussion Help

hilmeijer — Thu, 08 Jan 2026 08:27:06 -0000

Such post-processing for paper-quality figures one could better do separately. Data for all curves are saved into mat-files in a folder Systems/diagram/ The manual and tutorial show you how to make the plot, and then you can edit this to your preference.

Xuan Li posted a comment on discussion Help

Xuan Li — Thu, 08 Jan 2026 06:58:23 -0000

I can get frequency response curve plot by setting certain parameters value such as Figure 1. If I want to explore effect of one parameter (e.g., damping ratio) on frequency response properties, how can these curves with changing parameters be plotted in one figure, such as Figure 2? Or, can the data of one curve be saved to plot in one figure for showing multiple response curves?

GEOGE posted a comment on discussion Open Discussion

GEOGE — Sun, 04 Jan 2026 09:54:56 -0000

Thank you so much!!I have solved this problem .

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Sat, 03 Jan 2026 19:20:30 -0000

On the left, your system reads as M dy/dt with y=(a1,b1,a2,b2) and a matrix M, so it is completely coupled. In the syntax we really expect a1'=.... b1'=.... and so on, in that order, that's what the error message refers to. You could still apply the inverse of M to both sides to arrive at that form.

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Sat, 03 Jan 2026 19:15:54 -0000

Here we discuss issues with the software, not the use, one should do research themselves. And perhaps the finishing remarks in that document need to be spelled out explicitly: 1. My first concern is that the response for a 2DOF-system is not purely periodic, but more likely it's a torus. Continuation will not help you as continuation of tori is not supported, so you may be better of with long time simulations. (In contrast to the 1DOF-oscillator mentioned in the tutorial). 2. My second concern is...

Elahe Rajabi posted a comment on discussion Open Discussion

Elahe Rajabi — Sat, 03 Jan 2026 14:08:36 -0000

dear @hilmeijer would you please help me to figure out how to study the effect of changing one parameter in the frequency response curve? thank you

GEOGE posted a comment on discussion Open Discussion

GEOGE — Sat, 03 Jan 2026 08:46:46 -0000

I have rewrite the equations ,but there is still the problem.could you help me check?

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Fri, 02 Jan 2026 19:43:14 -0000

Apply the procedure as above, rewrite your equations first to a system of first-order ODEs.

GEOGE modified a comment on discussion Open Discussion

GEOGE — Fri, 02 Jan 2026 17:07:23 -0000

Dear hilmeijer：I have the same problem could you help me ?!!

GEOGE posted a comment on discussion Open Discussion

GEOGE — Fri, 02 Jan 2026 17:06:09 -0000

Dear hilmeijer：Thank you very much for your help, it is with your help that I have solved the problem.

Elahe Rajabi posted a comment on discussion Open Discussion

Elahe Rajabi — Wed, 31 Dec 2025 09:30:54 -0000

Hi community i want to model a 2dof nonlinear oscillating system and observe the effect of changing the nonlinearity term. I reached the frequency response of the system by following the document "Frequency response of nonlinear oscillator" by H. Meijer. Now I need to plot a 3d bifurcation curve to change one of the parameters of the system and plot the amplitude over a range of frequency. I would be so thankful if anyone could help me. What should I do now? i am using Matlab R2022, and MatcontM...

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Wed, 17 Dec 2025 22:02:03 -0000

This is not clear to me, I have been told it works up to some extent (in command line) but not all functions and commands will work. You will have to try and do this yourself.

Muhammad Adil Rehman modified a comment on discussion Open Discussion

Muhammad Adil Rehman — Wed, 17 Dec 2025 13:58:33 -0000

I would like to ask, if it is possible to use matcont with gnu octave? I have to use matcont for doing the frequency response analysis

Muhammad Adil Rehman modified a comment on discussion Open Discussion

Muhammad Adil Rehman — Wed, 17 Dec 2025 13:07:02 -0000

I would like to ask, if it is possible to use matcont with gnu octave as my organization's license to MATLAB is ended? But I have to use matcont for doing the frequency response analysis

Muhammad Adil Rehman posted a comment on discussion Open Discussion

Muhammad Adil Rehman — Wed, 17 Dec 2025 13:05:37 -0000

I would like to ask, if it is possible to use matcont with gnu octave as my organization's license to MATLAB is ended?

Alois Steindl posted a comment on discussion Open Discussion

Alois Steindl — Tue, 09 Dec 2025 22:23:38 -0000

Hello, your equation for y8 looks somewhat strange, I guess you forgot some *-signs. What are dy1 and dy2? Are you looking for steady states? If the problem occurs for y1 and y8, it should be easy to find the corresponding stationary solutions from the y1-y6-equilibria., because y7 and y8 do not appear in these equations. You could also solve these 2 equations separately. Good luck Alois

Sheng Gui Zhu posted a comment on discussion Open Discussion

Sheng Gui Zhu — Mon, 08 Dec 2025 08:31:20 -0000

Hello, I have downloaded and installed MatCont7p6; I am using Matlab 2022a. My system is: name: CCCC time: t cooedinates: y1, y2, y3, y4, y5, y6,y7,y8 parameters:I1, C1, K1, Fz, PL, PR, Kv, D1, r, L_val, R_val, H_val, V_val, C2, K2, W, K3, I2, I3, mn, cn, kn, d derivatives: SSSNN userfunctions: (none) equations: CcL = 2.0539 - 1.0823 * PL; CcR = 2.0539 - 1.0823 * PR; KvL = (0.813 * PL - 0.024) * Kv; KvR = (0.813 * PR - 0.024) * Kv; FzL = (1 - (KvL * D1 / Fz) * sin(y1 * sin(r) + y3)) * Fz / 2; FzR...

Alois Steindl posted a comment on discussion Open Discussion

Alois Steindl — Sun, 30 Nov 2025 21:03:52 -0000

Frequently matcont starts far away from the initial guess. but usually continuation helps to reach the desired range. I guess this is related to the implemented algorithm for creating the first solution. and sometimes it occurs, when the parameter values are changed a little bit.

Alois Steindl posted a comment on discussion Help

Alois Steindl — Sun, 30 Nov 2025 20:57:32 -0000

You could set the damping and the excitation to zero and look for periodic solutions of the remaining autonomous, conservative system. Since the system is conservative, the periodic solutions will be neutrally stable.

hilmeijer posted a comment on discussion Help

hilmeijer — Sun, 30 Nov 2025 06:16:16 -0000

No, there is no such tutorial. You refer to a theoretical result, that's not what we treat in this forum.

hilmeijer posted a comment on discussion Help

hilmeijer — Sun, 30 Nov 2025 06:14:16 -0000

There are so many details missing in your story. Please consider someone who is not looking at your screen and does not know your equations. "I plotted only the stable portion"; let's rephrase to "I re-simulated the last part after transients"? Suggestion: Untick "Pseudo-Arclength/Moore-Penrose" in the Continuer window OR simply extend the curve (many times).

Jinming Fan posted a comment on discussion Help

Jinming Fan — Sat, 29 Nov 2025 16:22:18 -0000

I want to plot the frequency response curve of a parametric vibrating beam, which, as is well known, consists of equilibrium points and limit cycle.I first used Floquet theory to locate the possible resonance peaks. Then, I plotted a time history using w=20. Ignoring the beginning of the time history, I plotted only the stable portion. Based on this stable limit cycle, I plotted the frequency response curve.However, the w value on the time history plot is 20, but the first point when plotting the...

Jinming Fan posted a comment on discussion Open Discussion

Jinming Fan — Sat, 29 Nov 2025 16:17:16 -0000

Muhammad Adil Rehman posted a comment on discussion Help

Muhammad Adil Rehman — Fri, 28 Nov 2025 18:48:17 -0000

Is there any tutorial to find the backbone curve as shown by dash-dot line in the following image?

Xinzhu Guan posted a comment on discussion Help

Xinzhu Guan — Mon, 24 Nov 2025 11:09:19 -0000

thanks！

Xinzhu Guan posted a comment on discussion Help

Xinzhu Guan — Mon, 24 Nov 2025 11:09:10 -0000

thanks！

Alois Steindl posted a comment on discussion Help

Alois Steindl — Mon, 24 Nov 2025 09:11:04 -0000

Hello,. why do you think there should be a LP point? Just follow your branches and see, what happens. These need not be connected. What happens to the left of the second curve? I can only second Hil's response: The authors of MatCont cannot solve the users' problems, If you need help, you should take significantly more effort to explain your model and your efforts so far; in your case also the reasoning for your expectations. Kind regards Alois Steindl

hilmeijer posted a comment on discussion Help

hilmeijer — Mon, 24 Nov 2025 08:19:26 -0000

It is always great if the potential of MatCont is explored, but it is an advanced tool. One needs some background knowledge and/or experience in nonlinear dynamics to use it. I am sorry, this does not look like a bug or feature to solve, we do not have time to help. But here is my intuition: The appearance happens "far away" and is not related to a trivial equilibrium, hence you cannot find it immediately with continuation.

Xinzhu Guan posted a comment on discussion Help

Xinzhu Guan — Mon, 24 Nov 2025 03:36:31 -0000

Dear professor, I'm studying this biomathematical model which I want to draw a bifurcation diagram with "b" as the parameter.I calculated that there is one positive equilibrium point when b=0.1, and two positive equilibrium points when b=1. Therefore, theoretically, there should be a “LP” point appearing in the bifurcation diagram with respect to “b”, but it does not show up in the plot. I hope you can help me take a look at this.

Alois Steindl posted a comment on discussion Help

Alois Steindl — Tue, 11 Nov 2025 18:59:02 -0000

Hello, it seems that your matcont system is in some strange state. Try to call matcont clean or matcont clean reset as proposed right at the start of matcont.m Good luck Alois

asdfghjkl posted a comment on discussion Help

asdfghjkl — Tue, 11 Nov 2025 15:00:56 -0000

I'm experiencing a critical startup failure in the MATCONT. The error occurs during initialization and prevents the toolbox from launching properly. Primary Error: "test_EP_BP" does not exist!

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Thu, 06 Nov 2025 16:12:32 -0000

Such conditional statements make the system non-smooth. For bifurcation analysis, we require derivatives to be well-defined, so as such, no it won't work. BUT you may be able to approximate your conditional expression with a smooth function: use a term with tanh(b (x-c)) or a 1/(1+exp(-b (x-c)); These are nearly zero where you need it, and the parameter b you can choose to make the switch steep.

Sobhan Mohammadi posted a comment on discussion Open Discussion

Sobhan Mohammadi — Thu, 06 Nov 2025 15:16:27 -0000

Thank you Prof. Meijer, Let me ask the first question differently. Does MatCont' GUI support conditional statement for piecewise non-smooth systems like for example, a simple Duffing oscillator with two different right-hand side (f(x) x>0 , g(x) x<0). A large number of papers employed slow-fast analysis with Matcont with needs defining conditional expression such as attached.

Sobhan Mohammadi posted a comment on discussion Open Discussion

Sobhan Mohammadi — Thu, 06 Nov 2025 15:16:26 -0000

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Thu, 06 Nov 2025 08:26:34 -0000

Regarding point 1; I simply cannot follow you. This forum is for questions related to the use of MatCont, not about modelling or specific equations. When you force a system periodically, then you mostly look at the (periodic) response, so limit cycles, not equilibria. Regarding point 2; Yes, for bifurcation analysis and continuation MatCont expects an autonomous ODE X'=F(X) and in your case X=(x,y,u,v).

Sobhan Mohammadi modified a comment on discussion Open Discussion

Sobhan Mohammadi — Thu, 06 Nov 2025 01:03:22 -0000

Thank you professor. I ask a few more questions here related to this part. 1- For fingding equilibrium point, the autonomous form is used in papers. According to the attached piece of paper, how we can write the slow variable (\delta =sin(wt)) as conditional expression based on Z+ and Z-? I think something is wrong in transforming non-autonomous original ODE to the autonomous form used in slow-fast systems analysism because very simpler equations exhibit more bifurcations including folding point,...

Sobhan Mohammadi posted a comment on discussion Open Discussion

Sobhan Mohammadi — Thu, 06 Nov 2025 00:34:17 -0000

Thank you professor. I ask a few more questions here related to this part. 1- For fingding equilibrium point, the autonomous form is used in papers. According to the attached piece of paper, how we can write the slow variable (\delta =sin(wt)) as conditional expression based on Z+ and Z-? I think something is wrong in transforming non-autonomous original ODE to the autonomous form used in slow-fast systems analysis. 2- for finding limit cycle I should use the form (u,v) in the previous question?...

hilmeijer posted a comment on discussion Help

hilmeijer — Fri, 31 Oct 2025 16:08:39 -0000

Cannot help at this stage: (1) I cannot read those characters (chinese?) (2) there are no further details, so no way one could understand the problem you encounter.

d_y posted a comment on discussion Help

d_y — Fri, 31 Oct 2025 14:52:07 -0000

I am drawing a one-parameter bifurcation diagram. When calculating backwards from a certain value of the parameter, it should theoretically reach a saddle-node bifurcation, but it does not show up as shown in the figure. Another problem is that the monitor does not display numerical values. How can I solve these issues?

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Sat, 25 Oct 2025 12:59:47 -0000

You're looking at a periodically forced oscillator. As soon as u,v are not zero, there is no equilibrium, so it should fail, as it does. Instead you may look for a limit cycle, see https://meijerhge.personalweb.utwente.nl/MatCont/FrequencyResponse.pdf

Sobhan Mohammadi posted a comment on discussion Open Discussion

Sobhan Mohammadi — Sat, 25 Oct 2025 01:11:01 -0000

Hello, I am trying to finding equilibrium points of an oscillator. Despite time solution of the system goes well (see pic1), after choosting the final point as initial condition, Matcont is unable to find equilibrium points regardless what I change in the setting. Even when I solve the equations via ODE45 for long time and enter the final values as initial condition, that does not work too. The definition of system of equation and settings are attached, please share your comments for this issue.

Sheng Gui Zhu posted a comment on discussion Open Discussion

Sheng Gui Zhu — Sat, 18 Oct 2025 02:35:24 -0000

Hello, I have downloaded and installed MatCont7p6; I am using Matlab 2022a. As shown in the figure, it is a double bifurcation. The horizontal and vertical coordinates correspond to a parameter. How is the curve that passes through the HH point drawn? I sincerely hope you can provide guides and help. Thank you in advance for your time and consideration. With best regards.

Sheng Gui Zhu posted a comment on discussion Open Discussion

Sheng Gui Zhu — Sat, 18 Oct 2025 01:18:00 -0000

thank you!!!

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Fri, 17 Oct 2025 08:56:48 -0000

I've pasted your system in Matcont7p4 and MatCont7p6 but using Matlab2023b. Compiled it without problems. Sorry, I cannot reproduce your error, so I don't know... Perhaps rely on numerical derivatives only?

Sheng Gui Zhu posted a comment on discussion Open Discussion

Sheng Gui Zhu — Fri, 17 Oct 2025 04:37:23 -0000

Hello, I have downloaded and installed MatCont7p6; I am using Matlab 2022a. My system is: name: CCCC time: t cooedinates: y1, y2, y3, y4, y5, y6 parameters: I1, I2, I3, C1, K1, Fz, PL, PR, Kv, D1, r, L, R, H, V, C2, K2, W, K3 derivatives: SSSNN userfunctions: (none) equations: CcL = 2.0539 - 1.0823 * PL; CcR = 2.0539 - 1.0823 * PR; KvL = (0.813 * PL - 0.024) * Kv; KvR = (0.813 * PR - 0.024) * Kv; FzL = (1 - (KvL * D1 / Fz) * sin(y1 * sin(r) + y3)) * Fz / 2; FzR = (1 + (KvR * D1 / Fz) * sin(y1 * sin(r)...

hilmeijer posted a comment on discussion Help

hilmeijer — Mon, 06 Oct 2025 20:29:53 -0000

Finally some time to look into this. I can see the warnings&errors appear, but digging through I observe another problem. Your system is badly scaled, with such large values of the parameters and coordinates, and when I follow the code, I observe that the dimension of the stable manifold is zero. That leads to missing equations and hence the mismatch in dimensions. Try to rescale your system so that the numerics do not suffer from that, or locate the BT-point with more precision.

Yiyun Wang posted a comment on discussion Help

Yiyun Wang — Wed, 01 Oct 2025 08:36:00 -0000

Hello, I have downloaded and installed MatCont7p6; I am using Matlab 2024b. My system is: X'=Lambd-betZ/(b+Z)XY-muuX Y'=betZ/(b+Z)XY-alphZY-muuY Z'=p(1-etalphZY/(a+alphZY))Z-(m_0+m_1Z)Z where Lambd,bet,muu,alph,p,et,a,m_0,m_1 and b are parameters and X,Y,Z are coordinates, and I choose the first and second order derivatives to be calculated symbolically, and others are calculated numerically. After the continuation of the limit point curve, I found two BT points(which I believe indicates the existence...

Wei Jian posted a comment on discussion Open Discussion

Wei Jian — Fri, 26 Sep 2025 08:09:41 -0000

Davide Liessi posted a comment on discussion Open Discussion

Davide Liessi — Thu, 25 Sep 2025 10:48:05 -0000

Can you please copy&paste your input equations here as text (not as an image)? Thank you.

Wei Jian posted a comment on discussion Open Discussion

Wei Jian — Wed, 24 Sep 2025 01:50:52 -0000

Dear Davide！ thank you very much for your reply! I have modified the import method according to your solution and requirements, and successfully imported the equation. However, I found that the interface for selecting the initial point could not pop up, and matlab issued a warning prompt, making it impossible to proceed with the subsequent run.

Davide Liessi posted a comment on discussion Open Discussion

Davide Liessi — Mon, 22 Sep 2025 11:01:58 -0000

Dear Wei Jian, sorry for letting you wait. I looked into your system and your input and I see the following problems. In your input there are two equations for each of y1, y3 and y5, while only one should appear, specifically the differential one. If you want to use the names psi, delta and q for those coordinates (to keep closer to the mathematical notation), you certainly can: just declare them in the coordinates field and use them instead of y1, y3 and y5. (I would even suggest, for clarity, to...

Wei Jian posted a comment on discussion Open Discussion

Wei Jian — Thu, 11 Sep 2025 01:39:11 -0000

Dear Professor Hilmeijer! Thank you very much for your reply. When I imported matcont, it would prompt "no delay found"

hilmeijer posted a comment on discussion Open Discussion

hilmeijer — Wed, 10 Sep 2025 15:54:31 -0000

This requires further investigation; we need to see if the syntax for the delay works the way you think it does, and want it to.

Wei Jian posted a comment on discussion Open Discussion

Wei Jian — Wed, 10 Sep 2025 12:05:39 -0000

Dear Professor Hilmeijer! Recently, I have been using the new feature of matcont to solve the delay system, but writing it as a dde file cannot be imported into matcont. I represent y5[t] as q[a,t] also as q[t], where a is already a constant. Also, since the speed v is a variable, can matcont recognize q[a,t-2*a/v]? How should this item be expressed and are there any other questions that enable matcont to solve this delay system? I hope the professor can answer my doubts. Thank you very much!!

hilmeijer posted a comment on discussion Help

hilmeijer — Wed, 20 Aug 2025 10:46:05 -0000

It is still there. You can find it at another place. Main Menu --> Select --> Manage Userfunctions. Here you can add these to the current system.

hilmeijer posted a comment on discussion Help

hilmeijer — Wed, 20 Aug 2025 07:13:55 -0000

This is always nontrivial and requires lots of work. What you can do is set Omega=0.6, and then simulate first with the forcing kept the same, but systematically changing a state variable of the system you're forcing, e.g. $z$. At some point the simulation should start to differ. If it is a subharmonic, then also adjust the guess for the period.

Xuan Li posted a comment on discussion Help

Xuan Li — Wed, 20 Aug 2025 06:52:53 -0000

Dear experts: If I want to get isolated branch solutions for frequency response (see figure attachment), I need to repeat simulation with different initial conditions via Matcont according to literature work. However, while I set different initial values of x and x_dot (x and y in Matcont), they are changed and remains nearly same for each operation through selecting "P Last Point" after "Extend" simulation. Detailed conditions can be seen in attachment figures. Finally, I only get same response...