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point plot over time displays wrong x-axis

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Hello,

I have a problem in post processing with the point plot in the Cross-Section Plot Parameteres.
I have a solver sequence of two time ranges: first from 0 to 37s in one step, then from 37 on in Nanosecond steps.
If I now want to plot for example the temperature at one point over the time I get a single vertical line at 37s. If I adjust the time axis to a Nanosecond range from 37 on, the single line stays. There is no increasing and decreasing over the time.
Does any body have/had the same problem by using two or more time ranges in a transient solver?
Or what can the problem otherwise be?
Thanks for all inputs!
Best regards, C.Mannal

2 Replies Last Post Mar 31, 2010, 3:17 p.m. EDT

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Posted: 1 decade ago Mar 31, 2010, 7:42 a.m. EDT
I've got the same problem when I am trying to plot a function in Nanosecond range, but with Seconds before, like the following:

(flc2hs(t-37.270000001,1e-9)-flc2hs(t-37.27000001,8e-9))
The same function without the 37.27 is plotted right.

Is that a general problem in Comsol?
Maybe there is a possiblity to change a range value somewhere or something like that?

Thanks again, best regards!

C. Mannal
I've got the same problem when I am trying to plot a function in Nanosecond range, but with Seconds before, like the following: (flc2hs(t-37.270000001,1e-9)-flc2hs(t-37.27000001,8e-9)) The same function without the 37.27 is plotted right. Is that a general problem in Comsol? Maybe there is a possiblity to change a range value somewhere or something like that? Thanks again, best regards! C. Mannal

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago Mar 31, 2010, 3:17 p.m. EDT
Hi

I'm not that astonished, going from tens of seconds to nano-seconds is still some 10 orders of magnitude, if you take a look on the binary number representation after IEEE 754 you will see that we have only some 7 digit resolution in single precision.
So I suspect you have "simple" a scaling issue, try to reduce the extend of the range and probably it will work beter.

1 to 10^10 is about like comparing te length of a football field to the average distance earth - sun = 1 AU

Good luck
Ivar
Hi I'm not that astonished, going from tens of seconds to nano-seconds is still some 10 orders of magnitude, if you take a look on the binary number representation after IEEE 754 you will see that we have only some 7 digit resolution in single precision. So I suspect you have "simple" a scaling issue, try to reduce the extend of the range and probably it will work beter. 1 to 10^10 is about like comparing te length of a football field to the average distance earth - sun = 1 AU Good luck Ivar

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