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Offline TheWizEd  
#1 Posted : 09 January 2011 18:30:22(UTC)
TheWizEd


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I'm having a problem with summation.

I am comparing the area calculation with a known solution. First I use sum. The result is incorrect.



So I check it using a different method. Result is correct.



Check against an Excel solution. Result is correct.



Am I misinterpreting the sum function? Sad

http://smath.info/wiki/G...eWizEd%2fsectionprop.zip

Edited by user 09 January 2011 18:35:03(UTC)  | Reason: Not specified

Ed

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Offline omorr  
#2 Posted : 10 January 2011 12:35:51(UTC)
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Hello Ed,

I think there is a bug in the summation operator.
Open in SMath Cloud
These two results should be the same, but they are not. I can not figure out how the summation operator get that number?
Here is another example - I am also puzzled here???
t←mat(2,5,1,2,2,2)
el(t,1,1)*el(t,2,2)-el(t,2,1)*el(t,1,2)=-1
sum((el(t,1,1)*el(t,2,2)-el(t,2,1)*el(t,1,2)),n,1,1)=3

Regards,
Radovan

Edited by user 10 January 2011 12:56:18(UTC)  | Reason: Not specified

When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!"
thanks 1 user thanked omorr for this useful post.
on 10/01/2011(UTC)
Offline TheWizEd  
#3 Posted : 10 January 2011 22:04:59(UTC)
TheWizEd


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Radovan,

Thanks for the help.

I can get around it by a user function for now.

Ed
Ed
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