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4 votes
Accepted

Singularity or stiff of system suspected

There is a typo in predator equation. We can compare Jacobian to that in the paper as follows ...
Alex Trounev's user avatar
  • 46.2k
4 votes
Accepted

Boundary conditions issue with Laplace equation

We can use OpenCascadeLink to generate mesh for this problem as follows (note, we rescale l, r, rs because the solution does not ...
Alex Trounev's user avatar
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2 votes
Accepted

How to Solve a DAE System with Integral Constraint and Moving Boundary in Mathematica?

To compute constraint, we can use code as it is with a small modification as follows ...
Alex Trounev's user avatar
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2 votes

Boundary conditions issue with Laplace equation

In Version 14.0 this works: ...
user21's user avatar
  • 40.1k
1 vote

Solving a stiff non-linear initial value ODE for a set of parameters

There is a typo with WhenEvent usage in the code. In the computation process Z becomes very small and negative that lids to the complex solution. Therefore the ...
Alex Trounev's user avatar
  • 46.2k
1 vote

Finding and Plotting Minima

You can use ComplexExpand to get rid Abs and so forth, if z, ...
Goofy's user avatar
  • 3,570
1 vote

Boundary conditions issue with Laplace equation

It works if you remove one of the two balls. For example : : ...
andre314's user avatar
  • 18.7k

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