Answered

Does hyperbolic-solver really use a nonlinear solver?!

Sorry about that! Apparently this GUI is too sophisticated for me ;-) I think I got it this time. Bill

Does hyperbolic-solver really use a nonlinear solver?!

Sorry about that! Apparently this GUI is too sophisticated for me ;-) I think I got it this time. Bill

6 years ago | 0

Answered

Does hyperbolic-solver really use a nonlinear solver?!

Hi, I think that referring to gradient components in the form e.g. ux(1,:) is fine. But entering complicated nonlinear coeffi...

Does hyperbolic-solver really use a nonlinear solver?!

Hi, I think that referring to gradient components in the form e.g. ux(1,:) is fine. But entering complicated nonlinear coeffi...

6 years ago | 0

Answered

Does hyperbolic-solver really use a nonlinear solver?!

Oh, sorry, I thought you were using the documented hyperbolic function. I'm afraid I have no idea why your code isn't doing wha...

Does hyperbolic-solver really use a nonlinear solver?!

Oh, sorry, I thought you were using the documented hyperbolic function. I'm afraid I have no idea why your code isn't doing wha...

6 years ago | 0

Answered

Does hyperbolic-solver really use a nonlinear solver?!

The first thing to check is that your version of MATLAB is R2012b or newer. The nonlinear hyperbolic (and parabolic) solvers hav...

Does hyperbolic-solver really use a nonlinear solver?!

The first thing to check is that your version of MATLAB is R2012b or newer. The nonlinear hyperbolic (and parabolic) solvers hav...

6 years ago | 0

Answered

Scalar PDE Coefficients in Function Form for the 'parabolic' pde solver

OK, so N is a very large number? parabolic calculates a single time-dependent solution from a single initial solution vector....

Scalar PDE Coefficients in Function Form for the 'parabolic' pde solver

OK, so N is a very large number? parabolic calculates a single time-dependent solution from a single initial solution vector....

6 years ago | 0

Answered

Scalar PDE Coefficients in Function Form for the 'parabolic' pde solver

Sorry, I'm not understanding your question. If you want to compute K (or M or F) for a specific u-vector, you can call assema...

Scalar PDE Coefficients in Function Form for the 'parabolic' pde solver

Sorry, I'm not understanding your question. If you want to compute K (or M or F) for a specific u-vector, you can call assema...

6 years ago | 0

Answered

Solving an elliptic PDE with a point source

Hi, As you've probably observed, PDE Toolbox doesn't support the du/dx term explicitly. However there is a trick you can try ...

Solving an elliptic PDE with a point source

Hi, As you've probably observed, PDE Toolbox doesn't support the du/dx term explicitly. However there is a trick you can try ...

6 years ago | 0

Answered

How to generate regular mesh in pde toolbox? (in a mutiple subdomain geometry)

I guess the first question is, what is the reason for the four subdomains? If the objective is simply to have different properti...

How to generate regular mesh in pde toolbox? (in a mutiple subdomain geometry)

I guess the first question is, what is the reason for the four subdomains? If the objective is simply to have different properti...

6 years ago | 0

| accepted

Answered

Why use triangular mesh when solving poisson equation in pde toolbox?

Hi, Because your domain is rectangular, you can use the poimesh function to generate a "regular" triangular mesh on that doma...

Why use triangular mesh when solving poisson equation in pde toolbox?

Hi, Because your domain is rectangular, you can use the poimesh function to generate a "regular" triangular mesh on that doma...

6 years ago | 0

| accepted

Answered

nonlinear heat transfer in a thin plate - error help

This example works only in R2012b (or newer) versions of MATLAB. If you are using one of these versions, please post the full e...

nonlinear heat transfer in a thin plate - error help

This example works only in R2012b (or newer) versions of MATLAB. If you are using one of these versions, please post the full e...

6 years ago | 0

Answered

How can I enter a source term which is a vector, to solve -div(cgradu)=F(F a vector)?

Yes, your pdebound function is incorrect for a system of PDE (N>1). Specifically, as this documentation page shows, http://w...

How can I enter a source term which is a vector, to solve -div(cgradu)=F(F a vector)?

Yes, your pdebound function is incorrect for a system of PDE (N>1). Specifically, as this documentation page shows, http://w...

6 years ago | 0

Answered

How can I enter a source term which is a vector, to solve -div(cgradu)=F(F a vector)?

I assume N is > 1? How did you define the first argument to assempde, b? I'm guessing that the problem at line 245 of assempde...

How can I enter a source term which is a vector, to solve -div(cgradu)=F(F a vector)?

I assume N is > 1? How did you define the first argument to assempde, b? I'm guessing that the problem at line 245 of assempde...

6 years ago | 0

Answered

Solving a system of PDE, not on the same control volume

Your pdefun function should look something like this: function [c,f,s] = pdefun(x,t,u,DuDx) if(x < L) k = a...

Solving a system of PDE, not on the same control volume

Your pdefun function should look something like this: function [c,f,s] = pdefun(x,t,u,DuDx) if(x < L) k = a...

6 years ago | 0

| accepted

Answered

Definition of the c coefficient for assempde

>Do you recommend to keep trying to resolve it with this pde tool? Yes, definitely. I'm almost certain that the 10-entry versio...

Definition of the c coefficient for assempde

>Do you recommend to keep trying to resolve it with this pde tool? Yes, definitely. I'm almost certain that the 10-entry versio...

6 years ago | 0

Answered

Solving a system of PDE, not on the same control volume

Hi, There is no difficulty using pdepe to solve your equation. You define xmesh over the full 2L length and, for best result...

Solving a system of PDE, not on the same control volume

Hi, There is no difficulty using pdepe to solve your equation. You define xmesh over the full 2L length and, for best result...

6 years ago | 0

Answered

Definition of the c coefficient for assempde

Hi, Your coefficients are sufficiently complicated that I'm not sure I understand all the issues, but hopefully I can at leas...

Definition of the c coefficient for assempde

Hi, Your coefficients are sufficiently complicated that I'm not sure I understand all the issues, but hopefully I can at leas...

6 years ago | 0

Answered

Definition of the c coefficient for assempde

Hi, Yes, you can solve your problem with PDE Toolbox. I recommend writing a MATLAB function to define your c-coefficient a...

Definition of the c coefficient for assempde

Hi, Yes, you can solve your problem with PDE Toolbox. I recommend writing a MATLAB function to define your c-coefficient a...

6 years ago | 0

| accepted

Answered

pdepe: Unable to meet integration tolerances without reducing the step size below the smallest value allowed

Hi, pdepe is designed for PDEs where the diffusion term is relatively large compared with the convection term. In your equat...

pdepe: Unable to meet integration tolerances without reducing the step size below the smallest value allowed

Hi, pdepe is designed for PDEs where the diffusion term is relatively large compared with the convection term. In your equat...

6 years ago | 0

| accepted

Answered

How is pdepe solving?

At the very bottom of the www page you show above is this reference: 1] Skeel, R. D. and M. Berzins, "A Method for the Spatia...

How is pdepe solving?

At the very bottom of the www page you show above is this reference: 1] Skeel, R. D. and M. Berzins, "A Method for the Spatia...

6 years ago | 0

| accepted

Answered

Why is the PDE Toolbox solving my parabolic equation incorrectly?

Hi, I have looked further into this issue of a divergent solution when n is positive but less than 2*pi^2. Not surprising...

Why is the PDE Toolbox solving my parabolic equation incorrectly?

Hi, I have looked further into this issue of a divergent solution when n is positive but less than 2*pi^2. Not surprising...

6 years ago | 0

Answered

Why is the PDE Toolbox solving my parabolic equation incorrectly?

Hi, I have already replied to your post in the MATLAB newsgroup but I guess you didn't see it. I've included the same inform...

Why is the PDE Toolbox solving my parabolic equation incorrectly?

Hi, I have already replied to your post in the MATLAB newsgroup but I guess you didn't see it. I've included the same inform...

6 years ago | 0

| accepted

Answered

How to solve a non-standard PDE using MATLAB pde-toolbox?

For a single dependent variable like you have, the c-coefficient can be a 2x2 matrix. That is explained on this documentation pa...

How to solve a non-standard PDE using MATLAB pde-toolbox?

For a single dependent variable like you have, the c-coefficient can be a 2x2 matrix. That is explained on this documentation pa...

6 years ago | 0

| accepted

Answered

Solving PDEs: Number of rows required in output of user defined coefficient functions

Hi Susannah, I think I can give you some help on this. I'll discuss the c-coefficient since that is the most complex one. ...

Solving PDEs: Number of rows required in output of user defined coefficient functions

Hi Susannah, I think I can give you some help on this. I'll discuss the c-coefficient since that is the most complex one. ...

6 years ago | 0

| accepted

Answered

What are the meaning of row 6 and 7 in the decomposed geometry matrix in matlab R2013b?

Hi, There were no changes to the decomposed geometry matrix in PDE Toolbox for the R2013b release. This documentation page is...

What are the meaning of row 6 and 7 in the decomposed geometry matrix in matlab R2013b?

Hi, There were no changes to the decomposed geometry matrix in PDE Toolbox for the R2013b release. This documentation page is...

6 years ago | 0

Answered

Strange behaviour of pde-toolbox in labeling or a bug?

Hi, The way I have dealt with the problem of defining coefficient matrices when I have had geometries similar to yours is to ...

Strange behaviour of pde-toolbox in labeling or a bug?

Hi, The way I have dealt with the problem of defining coefficient matrices when I have had geometries similar to yours is to ...

6 years ago | 0

Answered

Strange behaviour of pde-toolbox in labeling or a bug?

Hi, Your geometry is unusual in that none of the rectangles intersect each other. The algorithm in function decsg is designe...

Strange behaviour of pde-toolbox in labeling or a bug?

Hi, Your geometry is unusual in that none of the rectangles intersect each other. The algorithm in function decsg is designe...

6 years ago | 1

| accepted

Answered

How can I solve simultaneous PDEs using pdepe?

By "two pdes that are interlinked" do you mean that you have two PDE and two dependent variables, say, u1 and u2? If so, pde...

How can I solve simultaneous PDEs using pdepe?

By "two pdes that are interlinked" do you mean that you have two PDE and two dependent variables, say, u1 and u2? If so, pde...

6 years ago | 1

Answered

How to solve 2-D steady state heat conduction problem in MATLAB ?

MATLAB function pdepe can solve PDE in only *one* spatial dimension and time. The PDE Toolbox can solve PDE in two spatial di...

How to solve 2-D steady state heat conduction problem in MATLAB ?

MATLAB function pdepe can solve PDE in only *one* spatial dimension and time. The PDE Toolbox can solve PDE in two spatial di...

6 years ago | 0

Answered

explanation on boundary condition matrix

Have you looked at this page? <http://www.mathworks.com/help/pde/ug/assemb.html> There is a general description of the mat...

explanation on boundary condition matrix

Have you looked at this page? <http://www.mathworks.com/help/pde/ug/assemb.html> There is a general description of the mat...

6 years ago | 0

| accepted

Answered

get solution in spesific point in the domain after solving pde

There are several ways to do this. Here is one simple one: % p is the point matrix from initmesh % u is the solution f...

get solution in spesific point in the domain after solving pde

There are several ways to do this. Here is one simple one: % p is the point matrix from initmesh % u is the solution f...

6 years ago | 0

| accepted