Answered

Error in solving system of two reaction-diffusion equations?

The flux term in your pdex4pde function doesn't match the equations you show in your attached pdf. Assuming the pdf is correct,...

Error in solving system of two reaction-diffusion equations?

The flux term in your pdex4pde function doesn't match the equations you show in your attached pdf. Assuming the pdf is correct,...

3 years ago | 0

Answered

How can I solve an ODE when F(x0)=F'(x0)=0 is given at an unknown point x=x0 using bvp5c?

You have a second order ODE so you need two boundary conditions. The term "boundary condition" implies that you know the locatio...

How can I solve an ODE when F(x0)=F'(x0)=0 is given at an unknown point x=x0 using bvp5c?

You have a second order ODE so you need two boundary conditions. The term "boundary condition" implies that you know the locatio...

3 years ago | 0

Answered

Lack of Boundary Conditions to solve PDE (using pdepe function)

In your original code, set your boundary condition function to this: pl = [ul(1); 0]; ql = [0;1]; pr = [pi*exp(-t); 0...

Lack of Boundary Conditions to solve PDE (using pdepe function)

In your original code, set your boundary condition function to this: pl = [ul(1); 0]; ql = [0;1]; pr = [pi*exp(-t); 0...

3 years ago | 0

Answered

Solve a system of Partial Differential Equations using function BVP4C

It looks to me like you have 9 dependent variables and only 7 equations and boundary conditions. Clearly, that can't be solved....

Solve a system of Partial Differential Equations using function BVP4C

It looks to me like you have 9 dependent variables and only 7 equations and boundary conditions. Clearly, that can't be solved....

3 years ago | 1

Answered

Solving 4th order PDE

You may be able to solve this in pdepe with two equations and two dependent variables h and P. The first equation would be your ...

Solving 4th order PDE

You may be able to solve this in pdepe with two equations and two dependent variables h and P. The first equation would be your ...

4 years ago | 0

Answered

How to formulate boundary conditions for a PDE system?

pdepe is specifically designed for PDEs that are second-order in the spatial direction. That is why it requires you to specify b...

How to formulate boundary conditions for a PDE system?

pdepe is specifically designed for PDEs that are second-order in the spatial direction. That is why it requires you to specify b...

4 years ago | 0

Answered

Using pdepe for 1d transcient heat conduction through a composite wall

You want to model this multi-region wall with a *single* pde and then write your pde function (pdefun) so that it returns a d...

Using pdepe for 1d transcient heat conduction through a composite wall

You want to model this multi-region wall with a *single* pde and then write your pde function (pdefun) so that it returns a d...

4 years ago | 1

| accepted

Answered

Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.

I see two problems. First, your boundary conditions are incorrectly defined. They should be: pl = [ul(1);ul(2);ul(3);ul(...

Spatial discretization has failed. Discretization supports only parabolic and elliptic equations, with flux term involving spatial derivative.

I see two problems. First, your boundary conditions are incorrectly defined. They should be: pl = [ul(1);ul(2);ul(3);ul(...

5 years ago | 0

| accepted

Answered

How to solve a nonlinear Parabolic PDE IBVP

Since the problem is 1D, you can use the pdepe function.

How to solve a nonlinear Parabolic PDE IBVP

Since the problem is 1D, you can use the pdepe function.

5 years ago | 0

| accepted

Answered

pdepe: why does spatial discretization fail?

I think you want the following in your pdebc function: function [pl,ql,pr,qr] = pdebc(xl,ul,xr,ur,t) pl = ul-0.3639; ...

pdepe: why does spatial discretization fail?

I think you want the following in your pdebc function: function [pl,ql,pr,qr] = pdebc(xl,ul,xr,ur,t) pl = ul-0.3639; ...

5 years ago | 1

| accepted

Answered

PDE Toolbox solution array along a line, to then find the mean value

The evaluate function is returning only one value because the length of your x and y vectors is one. Maybe you want something l...

PDE Toolbox solution array along a line, to then find the mean value

The evaluate function is returning only one value because the length of your x and y vectors is one. Maybe you want something l...

6 years ago | 1

| accepted

Answered

Exchange Problem with PDEPE solver

Torsten said: "Usually, if e.g. material properties change at the interface, the transmission conditions are continuity of te...

Exchange Problem with PDEPE solver

Torsten said: "Usually, if e.g. material properties change at the interface, the transmission conditions are continuity of te...

6 years ago | 0

Answered

Spatial discretization has failed. (pdex1)

That error message is somewhat misleading. There are two problems in your code. The first is that your boundary condition fu...

Spatial discretization has failed. (pdex1)

That error message is somewhat misleading. There are two problems in your code. The first is that your boundary condition fu...

6 years ago | 0

Answered

How to solve second order partial differential equations ?

This problem is straightforward to solve using PDE Toolbox. I suggest you look at this example <http://www.mathworks.com/help/p...

How to solve second order partial differential equations ?

This problem is straightforward to solve using PDE Toolbox. I suggest you look at this example <http://www.mathworks.com/help/p...

6 years ago | 2

Answered

elliptic PDE with variable coefficient

The input arguments, x and y are equal length row vectors of x and y coordinates where the a coefficient must be defined. If t...

elliptic PDE with variable coefficient

The input arguments, x and y are equal length row vectors of x and y coordinates where the a coefficient must be defined. If t...

6 years ago | 0

| accepted

Answered

How to increase the size of "s" using pdegeom?

If your concern is about producing a nice looking plot from pdegplot, you will need to edit that function by changing the line:...

How to increase the size of "s" using pdegeom?

If your concern is about producing a nice looking plot from pdegplot, you will need to edit that function by changing the line:...

6 years ago | 0

| accepted

Answered

Interpolation of data defined on triangular mesh

If you have access to the R2014b version of MATLAB, there is a new PDE Toolbox function, pdeInterpolant, that makes this operat...

Interpolation of data defined on triangular mesh

If you have access to the R2014b version of MATLAB, there is a new PDE Toolbox function, pdeInterpolant, that makes this operat...

6 years ago | 1

| accepted

Answered

Nonlinear Heat Transfer In a Thin Plate - bug in example?

What version of MATLAB are you running? The documentation page you are pointing to is for the R2014b version of MATLAB. The ...

Nonlinear Heat Transfer In a Thin Plate - bug in example?

What version of MATLAB are you running? The documentation page you are pointing to is for the R2014b version of MATLAB. The ...

6 years ago | 0

Answered

Applying Nonconstant Boundary Conditions for pde

The pdeGeometryFromEdges function is part of a new, simpler approach to defining boundary conditions in PDE Toolbox introduced ...

Applying Nonconstant Boundary Conditions for pde

The pdeGeometryFromEdges function is part of a new, simpler approach to defining boundary conditions in PDE Toolbox introduced ...

6 years ago | 0

| accepted

Answered

Solving an Hamilton Jacobi Bellman equation type /w nonlinear coefficients

Hi Matt, You *can*, in fact, express your equation in a form that the parabolic function in PDE Toolbox will accept. The ...

Solving an Hamilton Jacobi Bellman equation type /w nonlinear coefficients

Hi Matt, You *can*, in fact, express your equation in a form that the parabolic function in PDE Toolbox will accept. The ...

6 years ago | 1

Answered

1D diffusion-reaction model across two-layered slab using pdepe

I am doubtful that pdepe can be used to solve this system. I suggest using finite differences to discretize in the spatial di...

1D diffusion-reaction model across two-layered slab using pdepe

I am doubtful that pdepe can be used to solve this system. I suggest using finite differences to discretize in the spatial di...

6 years ago | 0

| accepted