Author Topic: jumpy curves  (Read 3223 times)

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Offline esp

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jumpy curves
« on: October 31, 2012, 09:55 »
I ran a transmission calc for some time, covering some vgs points at one vds value ... the curve was very smooth .. i then restarted the job, to fill in some points, for example near the lowest current point .. the resulting new points made the curve very "jumpy" or unsmooth .. so my question is, is this somehow a function of the fact that I restarted the calculation, or is it really physical?  For example, suppose the current values are 1,2,3 at voltages 0.1, 0.2, 0.3, then I add another point at voltage 0.25, and the current comes out 1.8 ... this is the sort of thing I am talking about, ... I need to know if it is simply because I stopped the calculation and started again, or if i should consider those new points as valid as the original ones .. in other words, is there some history that atk needs when restarting a calculation?  I did in fact load the initial state properly, so i thought i was doing everything right, .. but since this was the first time i got a nice smooth curve, i was dissapointed that the new points from the new job ruined it .... what is happenning? thank you

Offline Anders Blom

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Re: jumpy curves
« Reply #1 on: October 31, 2012, 11:23 »
There is no difference if you restart from the file or the object in memory, if you are using an initial state in both cases. I'd be careful, in your case, if you are really, really running the correct combination of Vds and Vg, knowing the rather complex structure of your scripts ;)

Also, check that the calculations actually converged properly. You can also compare the transmission spectra, there is more information in those than in just the current value.

Offline esp

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Re: jumpy curves
« Reply #2 on: October 31, 2012, 17:52 »
Ok thank you