## 195 Reputation

10 years, 25 days

Amir

## Thank you...

Thank you So much

## problem with optimization procedure...

thank you so much for optimization procedure.

However, there was a problem of defining one variable which needs to be multiplied by 60 (it was typo in rouben's code). see my reply to rouben:

"

Everything is find with your answer except one mistake in replacing t with t_number. in my code, t=t_number[i] *60 (which is change of minutes to seconds) however, in your code, you didnt use 60. However, when I try to add 60 in your code, the solution would be different and it is equal to 0.0023.

"

So, when I multiply t_number by 60, the optimization code did not give the correct results (it should be 0.0023).

How can I correct that procedure?

## Everything is almost correct...

Thank you Rouben

Everything is find with your answer except one mistake in replacing t with t_number. in my code, t=t_number[i] *60 (which is change of minutes to seconds) however, in your code, you didnt use 60. However, when I try to add 60 in your code, the solution would be different and it is equal to 0.0023.

Many thanks for your help and I appreciate that

Thank you

## That's work...

Dear Preben

As always, I am most grateful for your help.

Thank you

## A revised...

Dear Preben

Actually, phi is the key part of my problem. Instead, I remove some terms including T_Bulk and tanh and now the code is simiplified. But, Still the code does not converge.

I would be most grateful if you help me.

Thank you

## Stupid Mistake...

MAny Thanks Preben. It was a stupid mistake.

Thanks.

## @Preben Alsholm    Thanks Preb...

Thanks Preben,

But, Do you sure that the code get the results for the case

Phiavg:=0.1:
EPSILONE:=0.5:
Nr:=30:
lambda:=0.1;
Ha:=5;
***NBT=0.2***

I run the code but it gaves me errors.

Here, I attach the code for this case.

MaplePrimes14-07-10odesysInt3(1).mw

Thanks

## Wow...

Thanks Preben. It is awesome.

You have always the best solution.

Could you tell me how you find the Guess? Can I have a mechanism that find an appropriate guess to get the results for lower values of NBT?

I get the results for a wide range of parameters, but I still have some problems for other cases.

For example:

Phiavg:=0.1:

EPSILONE:=0.5:
Nr:=30:
lambda:=0.1;
Ha:=5;

NBT=0.2 get error.

## What is the problem?...

Thanks.

It may help but does not improve the solution very much. I do not know what is the problem?

Why maple cannot give the solution for lower values of NBT? Is there a singularity or ...?

In addition, I observed some thing that may help. I printed the values of a[1] and a[2] and observed that these values reduced to about 1e-12. but, the solution continues and when these values are in the range of 0.01, get the results. It means that the solution procedure does not get the best results. Is there any chance to add a condition that when the values of a[1] and a[2] are about 1e-12, the solution get the resutls?

## Thanks...

Thanks preben. It improve my algorithm. However, as you mentioned we cannot go further NBT=0.44!

I dont know why we cannot get the results for NBt=0.1 and lower. (for some other cases, for example phiavg=0.02 and Ha=5 I get the results upto NBT=0.2)

What is wrong with the equations?

Is there any chance to get the results for lower values of NBT? for example change of variables or other numerical methods?

It should be mentioned that most of this code was written with your previous helps and I am very grateful for your helps.

Sincerely yours

Amir

## physical value...

Thanks Preben.

Actually, phi(1) should be (physically) positive.

Is there any chance to force the code that dont give the negative values of phi?

what about the convergence region? is there a chance the wide the region of convergence?

Dear Preben