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Bill Greene


Last seen: 7 days ago Active since 2014

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  • GitHub Submissions Level 1
  • Knowledgeable Level 3
  • 3 Month Streak
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pde1dM
pde1dm is a 1D PDE solver that supports high order interpolation functions, coupled ODE and is compatible with pdepe input synta...

2 months ago | 4 downloads |

Answered
PDEPE: Unable to meet integration tolerances without reducing the step size below the smallest value allowed
I have occasionally seen similar problems with pdepe in the past. I have written a PDE solver that has input similar to pdepe...

7 months ago | 0

Answered
Solving a system a coupled ODE and PDE
The error message is caused by your definition of the ode function: function [dydt] = ode_syst2(t, Tg, Ts, Fig, Fis) The defin...

8 months ago | 0

Answered
Appropriate method for solving coupled pdes
Yes, although it is true that the documentation for pdepe describes it as a solver for parabolic systems, it can often obtain...

10 months ago | 2

| accepted

Answered
Solving PDEs with mass conservation
I don't know how to integrate the dependent variables using pdepe. However, I have written a PDE solver with an input syntax sim...

10 months ago | 0

| accepted

Answered
Pdepe: Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.
The boundary conditions for your second PDE are invalid. These should work: pl = [0; 0]; ql = [1; 1]; pr = [ur(1)-cAO; 0]; q...

1 year ago | 1

| accepted

Answered
A system of PDEs which have one PDE with a spatial variable fixed term, u(x0, t)
pdepe is not really designed to handle systems of coupled PDE and ODE. However, I have written a PDE solver for MATLAB that has ...

1 year ago | 0

| accepted

Answered
Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.
Your boundary conditions for u2 (q=0, p=0 at each end) are not valid. The second equation in your system (u2_t=...) is, in fact...

1 year ago | 0

| accepted

Answered
How to define a step function as input BC in pdepe?
Here is the way you want to define such a BC: if(t>=50) pl = [ul(1);0]; else pl = [ul(1)-10;0]; end One thing you ha...

1 year ago | 0

Answered
PDE with time-dependent boundary conditions
I do not believe it is possible to solve this problem with pdepe. However I have written a one-dimensional PDE solver which i...

1 year ago | 0

| accepted

Answered
Problem about mixture of ode-pde
I have developed a PDE solver, pde1dM, that Ibelieve can solve your coupled PDE/ODE system. The solver runs in MATLAB and is s...

1 year ago | 1

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Answered
Solve heat equation with source term
T and m are referred to as dependent variables, not independent; x and t are the independent variables. This Example shows how t...

1 year ago | 0

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Answered
Unable to meet integration tolerances
Your equations have a fundamental error. Just calculate the "s" term along the length at the initial temperature and the problem...

1 year ago | 0

Answered
How to solve PDE problem
Your PDE can replaced by these two PDE which is a form acceptable to pdepe. However, pdepe, or in fact any numerical method,...

1 year ago | 1

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Answered
Solving second order PDE
The reason that pdepe imposes a boundary condition of the flux equal zero at the center is that this is required for the proble...

1 year ago | 0

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Answered
PDEPE: Unable to meet integration tolerances without reducing the step size below the smallest value allowed at time t.
You are trying to solve a system of ODE which is something pdepe is not designed for. Specifically, the pdepe documentation says...

1 year ago | 0

| accepted

Answered
1D Fourier equation with temperature dependent thermal properties
function [c,f,s] = pdex1pde(x,t,T,dudx,diffr,Tfront) diffr=3.34E-10*T^4 - 9.37E-07*T^3 + 9.38E-04*T^2 - 4.80E-01*T + 2.09E+02; ...

1 year ago | 0

Answered
how can I code a system of 2 pdes and an ode for modelling a packed bed
I did some experimentation with your code. Here are a couple of comments related to the changes I made: Because the equations a...

1 year ago | 0

Answered
PDE system - pdepe system example - error or incomplete description on Matlab website?
Looks like you have found an error in this documentation page. If you look at equation 3 in the referenced paper you will see th...

2 years ago | 0

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Answered
Pdepe: Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.
Your boundary conditions (BC) are specified incorrectly; a qr(i) value of zero and pr(i)=constant is not a valid BC. Since you ...

2 years ago | 0

| accepted

Answered
PDEPE: Unable to meet integration tolerances for large values of Ra
The convergence problem you are seeing is due to the strong boundary layer effect near , i.e. the solution is undergoing a shar...

2 years ago | 0

Answered
How to define stepchanges, variable BC for different timeintervalls using pdepe?
The reason that your code didn't show a change in the BC with time is due to the programming error that Torsten pointed out. If ...

2 years ago | 1

| accepted

Answered
Euler-Bernoulli's beam ODE or PDE
Take a look at this example: beam dynamics with pdepe

2 years ago | 0

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Answered
Solving advection diffusion pde
The only problem I see with your code is in the boundary conditions. I corrected your bcfun function and have attached my versio...

3 years ago | 1

Answered
Moving boundary problem with Stefan condition (modeling mass and heat transfer for sublimation front)
I think you may be able to solve this problem using the |pdepe| function. The idea is that you model both phases as a single re...

3 years ago | 0

Answered
Error using pdepe - Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.
The fundamental cause of your problem is that your initial conditions are inconsistent with your boundary condition at |x=0|. M...

3 years ago | 0

| accepted

Answered
How to rewrite a PDE equation and set the parameters for solving the temperature changes?
I think you can use |pdepe| to solve this but you need to include both the equation for Ts and the one for Tg; in your pde funct...

3 years ago | 0

Answered
How do I solve fourth order PDE numerically?
I have created an example, which might be of help, showing how to use the |pdepe| function to solve the beam equation : <https:...

3 years ago | 1

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Answered
How to speed up LU decomposition in ode15s solver?
You didn't provide any details of exactly how you are using |ode15s| but I suspect you can substantially improve the performance...

3 years ago | 0

| accepted

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