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August 22, 2006, 09:40 |
Error in Time Calculation in transition mode
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#1 |
Guest
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Hi Guys,
I have a weird error in my code. When my code is marching in time in transition mode, somewhere between T_0 and T_END an error in claculation of time is occured. As an example, for dt=0.1, at Time=5.9 the value of Time in next time step is calculated as Time=5.9999999999 instead of 6.0 or for dt=0.2, it happens in Time=23.2 and Time is 23.3999999 instead of 23.4. I used Double Precision for dt and Time variables but still I have this problem. I appreciate to receive your advise to fix this issue. Thanks Morteza |
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August 23, 2006, 06:51 |
Re: Error in Time Calculation in transition mode
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#2 |
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How do you advance the time: Do you keep adding dt to the previous time, or do you multiply dt with an integer number of time steps?
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August 23, 2006, 07:21 |
Re: Error in Time Calculation in transition mode
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#3 |
Guest
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Hi Mani,
It is just adding dt to previous time, Thanks Morteza |
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August 23, 2006, 07:54 |
Re: Error in Time Calculation in transition mode
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#4 |
Guest
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Hi Mani,
It is just adding dt to previous time, Thanks Morteza |
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August 24, 2006, 07:16 |
Re: Error in Time Calculation in transition mode
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#5 |
Guest
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This will be inherently inaccurate as you keep accumulating round-off errors. The general advice is to use an integer as increment (number of time steps) and obtain the current time by multiplication of that integer with dt.
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