emitxInput in ibsEmittance

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twatanabe
Posts: 22
Joined: 15 Jan 2009, 20:30

emitxInput in ibsEmittance

Post by twatanabe » 19 Apr 2011, 06:17

Dear Michael and colleagues,

It seems the switch "-emitxInput" does not affect on emitx in ibsEmittance calculation, doesn't it? It does for touschekLifetime, though.

Regards,

Takahiro

michael_borland
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Location: Argonne National Laboratory
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Re: emitxInput in ibsEmittance

Post by michael_borland » 19 Apr 2011, 08:02

Takahiro,

I think there was a bug in the last version, but it should be fixed in the latest release. Please try the latest version, if you are not using it now.

--Michael

twatanabe
Posts: 22
Joined: 15 Jan 2009, 20:30

Re: emitxInput in ibsEmittance

Post by twatanabe » 19 Apr 2011, 22:06

Hi Michael,

I think I am using the latest version. When I run the elegant, the output says "This is elegant 24.0.1, Jan 31 2011,,,,".
I installed the binary OS X executables "darwin-x86_elegant.tar.gz" on MacOS10.6.7. Today I re-installed it, but the situation is same.
What I see in my run is;
- First I run elegant for some lattice that I have been using without problem. As usual, I get the output file, like "sp8sr.twi".
- When I type something like "ibsEmittance sp8sr.twi sp8sr.ibs -charge=4.79 -coupling=1.0 -length=100.0", then "emitx" in sp8sr.ibs looks right. I mean, it is consistent with ex0 in the sp8sr.twi file.
(Here, I intentionally enter a big number for the length to easily check my calculation.)
- Next, I added the switch "-emitxInput=1.0e-10" at end of the ibsEmittance command, for instance. But "emitx" in sp8sr.ibs does not change.
- Further, if I type "sdds2stream sp8sr.ibs -param=emitxInput", then the answer is not 1.0e-10 (as I typed), but is 5.0e-11, which means that coupling=1 somehow affects on it. (Shouldn't 'emitxInput' in the output file be always same as input 'emitxInput'?)

Thank you,

Takahiro

michael_borland
Posts: 1927
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: emitxInput in ibsEmittance

Post by michael_borland » 20 Apr 2011, 08:24

Takahiro,

I can't reproduce the problem. Can you send the full commandline you are using and also post your input and output files?

--Michael

twatanabe
Posts: 22
Joined: 15 Jan 2009, 20:30

Re: emitxInput in ibsEmittance

Post by twatanabe » 21 Apr 2011, 04:36

Michael,

If you do not reproduce the problem, I must have made some mistake...
Attached are example files, including output files. Followings are the commands I entered:

> elegant sp8sr.ele > sp8sr.log
Then I checked the version of elegant shown in sp8sr.log, which was 24.0.1.
> sdds2stream sp8sr.twi -param=ex0
Then the answer was "3.4e-9".
> ibsEmittance sp8sr.twi sp8sr.ibs -charge=0.0001 -coupling=1.0 -length=400
> sdds2stream sp8sr.ibs -param=emitx
Then the answer was "1.7e-9", which looks good.
> ibsEmittance sp8sr.twi sp8sr.ibs -charge=0.0001 -coupling=1.0 -length=400 -emitxInput=1.0e-11
> sdds2stream sp8sr.ibs -param=emitx
Then the answer was still "1.7e-9".
> sdds2stream sp8sr.ibs -param=emitxInput
Then the answer was "5.0e-12".

Thank you for checking the problem.
Regards,

Takahiro
Attachments
sp8sr.zip
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michael_borland
Posts: 1927
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: emitxInput in ibsEmittance

Post by michael_borland » 21 Apr 2011, 08:12

Takahiro,

Unfortunately,the usage message for ibsEmittance is misleading. The emitxInput parameter only specifies the initial emittance. The equilibrium emittance, which is what you see in the standard calculation, is determined by the radiation integrals stored in the .twi file. Hence, it turns out that the equilibrium values don't depend on emitxInput, as you found.

The only use for emitxInput is when the -integrate option is given. This option allows computing the beam properties as a function of turn. Try adding -integrate=turns=100, then plotting (Pass, ex) as you vary emitxInput.

--MIchael

twatanabe
Posts: 22
Joined: 15 Jan 2009, 20:30

Re: emitxInput in ibsEmittance

Post by twatanabe » 26 May 2011, 03:38

Michael,

Thank you for your quick reply and sorry for my late reply. Now I understand that emitxInput parameter specifies the initial emittance instead of the emittance in the absence of IBS, and also that emitxInput should be used with the -integrate option.

Regards,

Takahiro

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