Mariusz Iwaniuk

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4 years, 143 days

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@Christopher2222

Update pdsolve ,numeric to solve partial differential equations for three,four(and more) independent variables.

And solve elliptic PDEsIt's been seven years now and Maple is still standing still.

Very briefly: Maple dosen't know the answer.

More info in Documentation:

?DESol

 

@Rouben Rostamian  

Mathematica better handle multidimensional integrals numerically than Maple :)

Harder  example:

Int(exp(-b^4-c^4-a^3), [a = b^2/(4*c) .. infinity, c = 0 .. infinity, b = -infinity .. infinity]);

#?

My workaround dosen't work very fast now, Maple calculations never ending.

 

MMA solve with about 2.88451 second.

@vv 

Oh, Yes my silly mistake.With correction answers are the same. 

Thanks.

@vv 

About volume, Mathematica gave me a different results:

@Ronan 

I2 := 2;

Optimization:-NLPSolve(I2*(I3-I1)/((I3-I2)*(I2-I1)), {I1+I2 >= I3, 0 <= I1, I1 <= I2, I2 <= I3}, assume = nonnegative);

#[Float(infinity), [I1 = 1., I3 = 2.]]

It's seems Maple FAILS in this case I3 = 2 ?

 

@rlopez 

Thanks for explanation.

Simulation in  MMA and another stuff.

@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.

 

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