Mariusz Iwaniuk

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3 years, 343 days

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@ecterrab 

 

It means that pdsolve is design to not solving PDE with weak solution?

Answer is simple, Maple is not a magic box that'll spit out a solution to any problem.

https://www.12000.org/my_notes/pde_in_CAS/pde_in_cas.htm

Probably  tripel integral is equal to Zero. My crystall ball that says.

Where is the integral ?

What have you tried?

@vv 

Workarounds always exist,but disgust always remains.

Thanks.

@Rouben Rostamian  

de := diff(u(x), x, x)+u(x)*(diff(u(x), x))-u(x) = exp(2*x);

bc := u(0) = exp(0), u(1) = exp(1);

dsol := dsolve({bc, de}, numeric,range = -1 .. 2);

plots:-odeplot(dsol, x = -1 .. 2, view = 0 .. 3);

dsol(2);

#Warnings and Errors ?

Where is my plot on rage -1..2 ?

It seems Mathematica is smarter than Maple.

 

@acer 

Thanks :)

@tschuermann 

Yes,I have this errors messagess from FindRoot.

Increasing in ParametricNDSolve to WorkingPrecision -> 25 helps.

 

My code is terribly slow and  needs to  completely for rework.

I do not have time for such a job.

I not a guru in Mathematica I'm still learning.

Maybe you can ask here.

HeunC_ver2.zip

 

@tschuermann 

For  table 40x40  and more probably you  need increase:

1.Digits:                      15 or 20

2.In dsolve:                abserr = 0.1e-50 ?

3. In dsolve:               changing: method=numericmethod (maybe there is a better method(faster))

4. In findroot code:   {guard::posint:=1,maxtries::posint:=1600} ?Explanation for these number See link. For table 40x40 is: posint:=1600

 

For sure computation times  increase very quickly.

 

@acer 

Hello

Can you explain,what is number 5 and 50 in this code below:

{guard::posint:=5,maxtries::posint:=50}

Thanks.

@tschuermann 

I attached MMA notebook if it's useful to you:HeunC.zip

 

@vv 

What is the correct answer, because I'm not sure of my answer for OP ?

@Markiyan Hirnyk 

MMA  11.3 says:

 

Is Mark Viola is wrong with his answer. It has 127K reputation?

 

What is the source of this plot? References ?

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