I need to plot bifurcation for SEIR model with dde_biftools and I need steps for that as I don't use this package in matlab before it's first time to deal with this pachage.
Plotting bifurcation diagrams for a System of Differential Equations (SDE) like the SEIR (Susceptible-Exposed-Infectious-Removed) model using dde_biftools typically involves the following steps. Please note that the actual steps might depend on the specific structure of your SEIR model and the software environment you are using. Here, I'll provide a general outline using MATLAB and dde_biftools:
Prerequisites:
MATLAB:Ensure that you have MATLAB installed on your system.
dde_biftools:Install dde_biftools, a MATLAB toolbox for bifurcation analysis of delay differential equations. You can download it from the official dde_biftools GitHub repository: https://github.com/pedrobcm/DDE-Biftool
Steps:
Define the SEIR Model: Write down the SEIR model equations as a system of delay differential equations. For instance, the SEIR model might be represented as: cssCopy codedS/dt = -beta*S*I dE/dt = beta*S*I - sigma*E dI/dt = sigma*E - gamma*I dR/dt = gamma*IWhere beta, sigma, and gamma are parameters, and S, E, I, and R are state variables.
Set Up dde_biftool: Initialize dde_biftool in your MATLAB environment. This involves adding the dde_biftool toolbox to your MATLAB path. matlabCopy codeaddpath('path_to_dde_biftool_folder')
Define the DDE System: Use dde_set and dde_solve to define and solve the delay differential equations. matlabCopy codesys_ode = @(t,y,Z) your_seir_model(t, y, Z, parameters); history = @(t) your_initial_conditions(t, parameters); delays = your_delay_times(parameters); sol = dde_solve(sys_ode, delays, history, t_span);
Plot Bifurcation Diagram: Use dde_biftool plotting functions to visualize the bifurcation diagram. matlabCopy codefigure; plot_branch(branch, 'parameter', bifpar, 'add_2_gcf', 1); xlabel(bifpar); ylabel('Steady State Value');
Explore Other Bifurcation Types:Investigate other bifurcation types such as Hopf bifurcations, period-doubling bifurcations, etc., using the corresponding dde_biftool functions.
Explore Parameter Space:Perform continuation analysis to explore how different parameters affect the bifurcation behavior.
Visualize Bifurcations:Use dde_biftool plotting functions to visualize bifurcations, including bifurcation points, stability regions, and periodic solutions.
This is a general outline, and you need to adapt these steps based on the specific structure and parameters of your SEIR model. Additionally, refer to the dde_biftool documentation and examples for more detailed guidance on using the toolbox for bifurcation analysis.