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Stiff Delay Differential Equations

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Ismaeel
Ismaeel il 10 Apr 2017
Risposto: Leo Sun il 23 Ago 2018
Does anybody know how to solve STIFF differential equations with delay in time? The solvers in Matlab (dde23,...) are for non-stiff DEs; they cannot be applied to stiff DEs with delay; I have tried all of them. Without delay, my problem can be solved using ode15s, ode23t, but not ode23, ode23tb. Thanks in advance

Risposte (2)

Torsten
Torsten il 11 Apr 2017
radar5 is your friend:
Best wishes
Torsten.
  1 Commento
Ismaeel
Ismaeel il 11 Apr 2017
Thanks Torsten for the reply. I have looked at the link and unfortunately, the code is written in Fortran language.

Accedi per commentare.


Leo Sun
Leo Sun il 23 Ago 2018
Hi there, I have a problem solving stiff delay differential equations recently. I just found that there's a paper written by Vikas Agrawal's group and they used a solver called "dde15s" for there calculation.
We can find the paper at the following website: https://onlinelibrary.wiley.com/doi/10.1021/bp034226s
At the bottom of the website, click "Supporting Information", and download the zip file "bp034226ssi20030804_024052.zip", which the dde15s.m is inside (or you may download the attachment form this comment).
But I found a new problem. I try to use dde15s instead of dde23 in my code, then the error appears:
Error using vertcat
Dimensions of matrices being concatenated are not consistent.
Error in dde15s>solextend (line 155)
solout.idata.kvec = [sol.idata.kvec; solex.idata.kvec(2:end)];
Error in dde15s (line 139)
sol = solextend(sol,solex);
In dde15s.m, function "solextend" is for Concatenate two solution structures produced by ODE15S. And the Author said " This function works with ODE15S from MATLAB 6.5, but it may require modifications to work with other versions."
I think the error exist in my code because I use the Matlab 2017a version. So is there anyone can fix that error and make "dde15s.m" fit to the newest version of Matlab?
Thanks for all your help.

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