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#51 2013-03-04 07:09:41

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,607

Re: Kummer and a tough integral.

Yes, it does.

But, what does it mean?


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#52 2013-03-04 07:14:20

bobbym
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From: Bumpkinland
Registered: 2009-04-12
Posts: 89,048

Re: Kummer and a tough integral.

Hmmm? Change that exp(-x) to sqrt(x) and change f(0,50 ) to f(0,1)


In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

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#53 2013-03-04 07:19:48

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,607

Re: Kummer and a tough integral.

It says "Romberg failed to converge".


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#54 2013-03-04 07:21:27

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 89,048

Re: Kummer and a tough integral.

Try adjusting rombergtol: 1.e-3


In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

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#55 2013-03-04 07:22:55

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,607

Re: Kummer and a tough integral.

It is working and giving out: 0.66653268137515


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#56 2013-03-04 07:28:03

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 89,048

Re: Kummer and a tough integral.

There should be a global variable called rombergit. What is its value?


In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

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#57 2013-03-04 07:33:06

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,607

Re: Kummer and a tough integral.

It is 11.


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#58 2013-03-04 07:35:18

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 89,048

Re: Kummer and a tough integral.

Set it  25. and rombergtol: 1.e-6, what happens?

You should know about these:

http://eagle.cs.kent.edu/MAXIMA/maxima_21.html

http://www.csulb.edu/~woollett/

get them if you do not.


In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Offline

#59 2013-03-04 08:03:18

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,607

Re: Kummer and a tough integral.

I get 0.66666657420034.

Thanks for the links. I will try 'em out.

Last edited by anonimnystefy (2013-03-04 08:06:28)


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#60 2013-03-04 08:08:59

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 89,048

Re: Kummer and a tough integral.

Here is more:

http://maxima.sourceforge.net/documentation.html

I got
romberg(1/(cos(x)+x^2), x, 0, 100);
1.828017700397752

which is accurate. By setting rombergit to 200 and rombergtol to 1E-10.

Now you need to get a bfloat in there somehow.


In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

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#61 2013-04-02 07:41:27

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,607

Re: Kummer and a tough integral.

Hi bobbym

How do I get more accuracy out of NIntegrate?


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#62 2013-04-02 07:43:06

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 89,048

Re: Kummer and a tough integral.

Easy, use WorkingPrecision-> some number.


In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Offline

#63 2013-04-02 07:51:05

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,607

Re: Kummer and a tough integral.

Ah, there it is. I found the AccuracyGoal and PrecisionGoal, but they didn't help.

Thanks!


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#64 2013-04-02 07:55:58

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 89,048

Re: Kummer and a tough integral.

WorkingPrecision did not work?


In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Offline

#65 2013-04-02 08:00:23

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,607

Re: Kummer and a tough integral.

It is working.


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

Offline

#66 2013-04-02 08:00:48

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 89,048

Re: Kummer and a tough integral.

The answer to d) i) is in the other thread.


In mathematics, you don't understand things. You just get used to them.

I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.

Offline

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