Problem with vary_element

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frank_stulle
Posts: 13
Joined: 04 Jun 2009, 04:58

Problem with vary_element

Post by frank_stulle » 18 Aug 2009, 03:40

Hello,
I tried to study some energy mismatch in my beam line using MALIGN and VARY_ELEMENT. I set up everything as proposed in the manual and the examples but got the following error messages:
"Error:
The following parameter name is invalid: >050DELTAE.DP<
(sddsconvert may be used to change the name)"

and

"Problem defining extra SDDS parameters in file rtml.fin (setup_output)"

Since I knew it should work, I tried several things and finally renamed the MALIGN element to TESTDELTAE. Now it works! Could it be that VARY_ELEMENT does not correctly process element names which start with a number?

Cheers
Frank

michael_borland
Posts: 1796
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: Problem with vary_element

Post by michael_borland » 18 Aug 2009, 09:04

Frank,

The problem is that the name of the element starts with a digit. While this is legal in elegant, it causes problems when elegant attempts to create a parameter in the .fin file corresponding to the varied quantity. The reason is that SDDS forbids names that start with digits, because it causes potential confusion in equations.

I'll have to think of a way to handle this. Meanwhile, renaming the element as you've done is the only work-around.

--Michael

frank_stulle
Posts: 13
Joined: 04 Jun 2009, 04:58

Re: Problem with vary_element

Post by frank_stulle » 18 Aug 2009, 09:42

Thanks for the quick answer. May be I missed it, but I could not find this information in the manual. It might be interesting to add this to the description of vary_element (or somewhere else).

Frank

michael_borland
Posts: 1796
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
Contact:

Re: Problem with vary_element

Post by michael_borland » 18 Aug 2009, 09:51

Frank,

I don't think you missed anything. It doesn't appear to be in the manual.

I'll add it. Thanks for the suggestion.

--Michael

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