Activity for Evgenij Gr.
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Evgenij Gr. posted a comment on discussion Open Discussion
Hello! In the system that I am studying, a Branch Point of Cycles bifurcation occurs during the single-parameter continuation of stable limit cycle. Since the system possesses discrete symmetries (permutations of some phase variables, also reflections), it is quite likely that in this case BPC might have lower codimension. Is it possible to compute this curve in Matcont, either directly or by using some workaround? The second question is related to the initializers that are available, when selecting...
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Dear Hil Meijer, thank you for your help! I guess I'll uncheck LPNS box for now. I also have two questions that are slightly related to my initial one: 1) is it possible in MATCONT to take, for example, R1 bifurcation point and continue it (as a curve) in three-dimensional parameter space? I don't remember seeing such example in the tutorials that I've read though... 2) is there a tutorial with a troubleshooting guide for when any of the default parameters should be changed, like number of mesh intervals...
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So, in order to reproduce the error, follow these steps. Step 1 Use the system Coordinates g1,g2,g3,g4 Parameters r,a,b Equations g1'=-0.2*r*sin(b - 2*g1) + 0.2*r*sin(b + 2*g1) - 0.2*r*sin(b - 2*g2) - 0.2*r*sin(b - 2*g3) - 0.2*r*sin(b - 2*g4) + 0.2*r*sin(b + 2*g1 - 2*g2) + 0.2*r*sin(b + 2*g1 - 2*g3) + 0.2*r*sin(b + 2*g1 - 2*g4) + 0.2*sin(a - g1) - 0.2*sin(a + g1) + 0.2*sin(a - g2) + 0.2*sin(a - g3) + 0.2*sin(a - g4) - 0.2*sin(a + g1 - g2) - 0.2*sin(a + g1 - g3) - 0.2*sin(a + g1 - g4) g2'=-0.2*r*sin(b...
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So, in order to reproduce the error, follow these steps. Step 1 Use the system Coordinates g1,g2,g3,g4 Parameters r,a,b Equations g1'=-0.2*r*sin(b - 2*g1) + 0.2*r*sin(b + 2*g1) - 0.2*r*sin(b - 2*g2) - 0.2*r*sin(b - 2*g3) - 0.2*r*sin(b - 2*g4) + 0.2*r*sin(b + 2*g1 - 2*g2) + 0.2*r*sin(b + 2*g1 - 2*g3) + 0.2*r*sin(b + 2*g1 - 2*g4) + 0.2*sin(a - g1) - 0.2*sin(a + g1) + 0.2*sin(a - g2) + 0.2*sin(a - g3) + 0.2*sin(a - g4) - 0.2*sin(a + g1 - g2) - 0.2*sin(a + g1 - g3) - 0.2*sin(a + g1 - g4) g2'=-0.2*r*sin(b...
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Oh, I can provide the necessary details for continuation that experienced this trouble. I can provide the system and step-by-step instructions to reproduce the error later, should I provide any additional information?
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Hello! This is the problem that I have encountered few times while doing continuation in MATCONT. I am using MATLAB R2021b with MATCONT7p3. This message is cryptic to me, even last warning and error in MATLAB output does not help to understand in what direction I should look in order to fix something. Thanks in advance for the help!
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Hello! This is the problem that I have encountered few times while doing continuation in MATCONT. I am using MATLAB R2021b with MATCONT7p3. This message is cryptic to me, even warnings and errors in MATLAB output does not help to understand in what direction I should look. Thanks in advance for the help!
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Hello! It seems that forced_spring.py has an example of a piecewise oscillator system. It also shows how to set up a proper hybrid model for such problems. Probably it has what you need. Documentation says: The point type MX is associated with some type of computational difficulty. It usually represents non-convergence based on our tolerances, but for many different reasons (e.g. initial point is too far from the requested curve type, too close to a homoclinic (large period), ...). As far I understand...
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Hello! I have the following problem with using PyCont for studying a system. The problematic output can be seen here. Let me describe what I was trying to achieve. For this system I know the equilibrium state that doesn't depend on the values of parameters. Also I know exact values of parameters at which Hopf bifurcation of this equilibrium happens. First I have tried to let PyCont find Hopf bifurcation point automatically. As I see, almost all PyCont examples on Github start from this step. The...
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Thanks fot the reply! I had some hopes for that way of handling the problem but okay, so much for that idea.
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Thank you for your answer! Yeah, calling separate script is a workaround that I currently have. I'll check your suggestion for splitting domain. I don't know whether it will work because mostly I integrate until trajectory returns to cross-section (I use terminal event for that). Maybe the return time is not as tame as I've expected and your suggestion can fix this. Can I ask about recreating generator here? What I've meant is that I delete folders with generated source code and library, recompile...
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Thank you for your answer! Yeah, calling separate script is a workaround that I currently have. I'll check your suggestion for splitting domain. I don't know whether it will work because mostly I integrate until trajectory returns to cross-section (I use terminal event for that). Maybe the return time is not as tame as I've expected and your suggestion can fix this. Can I ask about recreating generator here? What I've meant is that I delete folders with generated source code and library, recompile...
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Excuse me, what way of restarting integrator did you mean exactly? I've encountered the same problem with memory leak in Dopri/Radau and that way could be extremely useful to me. Somehow Generator's cleanupMemory method doesn't work at all (from the description I got the idea that it might solve problem, but no success) and I can't recompile RHS and recreate generator in a loop of a single script (first iteration is OK, at the second iteration something strange happens with paths and compilation...
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Excuse me, what way of restarting integrator did you mean exactly? I've encountered the same problem with memory leak in Dopri/Radau and that way could be extremely useful to me. Somehow Generator's cleanupMemory method doesn't work at all (from the description I got the idea that it might solve problem, but no success) and I can't recompile RHS and recreate generator in a loop of a single script (first iteration is OK, at the second iteration paths are screwed and compilation fails).
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Sorry, what way of restarting integrator did you mean exactly? I've encountered the same problem with memory leak in Dopri/Radau and that way could be extremely useful to me. Somehow Generator's cleanupMemory method doesn't work at all (from the description I got the idea that it might solve problem, but no success) and I can't recompile RHS and recreate generator in a loop of a single script (first iteration is OK, at the second iteration paths are screwed and compilation fails).
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Thank you very much, this helped a lot :) I think I there's only one important question...
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Thanks again for your help, it works! Still there are few moments that I want to...
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Thanks again for your help, it works! Still there are few moments that I want to...
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Hello, Rob! Thanks for the help! I think I got it better now: I thought the reason...
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Hello everyone! I was trying to simulate behaviour of system of ODEs subject to periodic...
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Thank you Vladimir! I've tried your suggestion (with one modification only - after...
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Hello Rob, thanks for suggestion! I've made changes locally, installed PyDSTool and...
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As far as I see, executing "echo $CFLAGS" and "echo $FFLAGS" in SMC terminal shows...
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So, finding compiler options environment variable and changing it might fix this...
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Hm, it seems that I've managed to use the latest version of PyDSTool from GitHub...
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Hello! Recently PyDSTool has been added as one of system-wide packages for Sage Math...
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