HOME and CAS unexpected behavior
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10-21-2022, 08:35 PM
Post: #1
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HOME and CAS unexpected behavior
Hi all,
One of my students mentioned to me that he was getting zero when calculating the result of a finite integral in HOME. I already had the solutionI calculated using a table of integrals so I could easily evaluate it in both HOME and CAS, and, lo and behold, I get 0.000E0 in HOME, 7.1054E-15 in CAS. The expression to evaluate is EXP(-2r/a) * (-2r^2/a^2 - 2r/a - 1) + 1 with r=0.877E-15 and a =5.290E-11 Any idea where is this behavior coming from?[/code] |
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10-22-2022, 06:04 PM
(This post was last modified: 10-22-2022 06:12 PM by rawi.)
Post: #2
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RE: HOME and CAS unexpected behavior
What are the lower and upper limit of the integral? And what is the variable to integrate?
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10-22-2022, 07:13 PM
Post: #3
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RE: HOME and CAS unexpected behavior
(10-21-2022 08:35 PM)mmadurga Wrote: I already had the solutionI calculated using a table of integrals so I could easily evaluate it in both HOME and CAS, and, lo and behold, I get 0.000E0 in HOME, 7.1054E-15 in CAS. Since you use table of integrals, I assumed it has nothing to do with integration routine. It may be due to massive cancellations, for F(hi) - F(lo) HOME has 12 decimals precisions, but CAS has more (53-5 = 48-bits, or about 14+ decimals) |
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