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12-Amethyst

## matrix finite difference method

I have problem with create matrix for a system of equations to solve. Please create it for me in mathcad.

19 REPLIES 19
21-Topaz II
(To:ptc-3682623)

Hi,

Image too small even after enlargement

24-Ruby V
(To:-MFra-)

@-MFra- wrote:

Hi,

Image too small even after enlargement

Have you tried clicking the "full screen" button?

Alternatively you may press the "zoom +" button multiple times.

As the preview now is rather slow, I find it more comfortable to download the pic (the small icon to the right of the file name) and view it using a local viewer.

21-Topaz II
(To:Werner_E)

Thank you very much.

12-Amethyst
(To:-MFra-)

21-Topaz II
(To:ptc-3682623)

12-Amethyst
(To:-MFra-)

The problem.jpg is the theam

21-Topaz II
(To:ptc-3682623)

You should add the boundary conditions as well.........

12-Amethyst
(To:-MFra-)

This items are not inportant can be 1.

21-Topaz II
(To:ptc-3682623)

Hi,

After determining a difference method for the boundary value problem, one must study its stability by applying the corresponding theorems. If the method is not stable, you must determine another that is stable.

To continue, I must dedicate some time that I do not have. Anyway I'll see what I can do. If you provided us, in a compressed folder, the file with the difference method you wrote, it would be a great advantage for us and you could get help from more people in the community.

12-Amethyst
(To:-MFra-)

ok. I need create K matrix in mathcad. only this is coefficients matrix of stiffness.

21-Topaz II
(To:ptc-3682623)

Hi,

could you be interested in the following simplification of the problem?

12-Amethyst
(To:-MFra-)

Wow:)That is it. Thanks

There is continuing of my problem

21-Topaz II
(To:ptc-3682623)

For a problem in one dimension, things are quite simple, as you can see from the attached example:

The example shown, however, is not one of the most suitable .......

12-Amethyst
(To:-MFra-)

Would you mind doing me sample for it:In attachment you will find sample

12-Amethyst
(To:-MFra-)

Would you like gew me your a done samlpe in mcd?

21-Topaz II
(To:ptc-3682623)

Excuse me, but I did not create any worksheet about it.

21-Topaz II
(To:ptc-3682623)

I tried to solve the system with pdesolve, providing the boundary conditions chosen by me at random, as you can see in the following image, but the method does not seem to converge towards a solution:

12-Amethyst
(To:-MFra-)

Thanks for your time:) This is not ok. You have only one boundary condition for u and 3 for w. I have to solve linear matrix finite difference method. Try use my solusion and help me write matrix K for my problem. Next step we will try use q and boundary condition and then solve linear method.

21-Topaz II
(To:ptc-3682623)

I see you want to use an implicit method to solve the system of partial differential equations. It would be better, however, to supply the equations, and all that is necessary, so that I can try to find a solution.

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