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Negative drift in sequence #93

coldfix opened this issue Jan 27, 2012 · 0 comments

Negative drift in sequence #93

coldfix opened this issue Jan 27, 2012 · 0 comments


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@coldfix coldfix commented Jan 27, 2012

Issue migrated from trac ticket # 93

component: core_sequence | priority: major | resolution: fixed

2012-01-27 18:26:29: luke.thompson commented

date: 2011.10.28
I'm having a problem with MAD-X 4.01.12; I've also reproduced this in MAD-X 5.00.08 which I believe is the latest version. When using SAVE to output a sequence file, MAD-X sometimes has problems with reading in the file it's just generated; it claims there are negative drifts, usually of a small value, for instance 1e-6. I've attached some files which, for me, produce this error. It appears truncation of position values is occurring in the saved sequence. Is there any way around this?

2012-01-27 18:27:12: @ldeniau uploaded file seq.test.madx (0.2 KiB)

2012-01-27 18:28:03: @ldeniau uploaded file (72.1 KiB)

2012-01-27 18:28:33: @ldeniau edited the issue description

2012-02-03 16:42:02: @ldeniau changed owner from ** to ldeniau

2012-02-03 16:42:02: @ldeniau changed status from new to assigned

2012-03-12 18:08:31: @ldeniau commented

date: 2012.03.12, from L. Thompson
I don't think this is a defect, rather a misunderstanding. I presumed that MADX would output values to the precision it was given them, so on reading in a sequence file with high precision values for elements I thought it would output the same values to a sequence file. I fixed my problem by using the SET, FORMAT="" command.

2012-03-12 18:08:31: @ldeniau set resolution to fixed

2012-03-12 18:08:31: @ldeniau changed status from assigned to closed

2012-03-15 17:56:47: @ldeniau changed resolution from fixed to **

2012-03-15 17:56:47: @ldeniau changed status from closed to reopened

2012-03-15 17:56:56: @ldeniau changed owner from ldeniau to laurent.deniau

2012-03-15 17:56:56: @ldeniau changed status from reopened to assigned

2012-03-15 17:57:02: @ldeniau changed resolution from ** to fixed

2012-03-15 17:57:02: @ldeniau changed status from assigned to closed

@coldfix coldfix closed this Mar 15, 2012
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