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Tim, I am sure you are right, it is just a visualization. Maybe just looking on projections can help to understand better. Regards, Stepan On 3/10/14, 10:50 PM, Nelson, Timothy Knight wrote: > Hi Stepan, > > I don't think it's this complicated. Rather, I think it's a simple > bug in the visualization, based on other bugginess in how it works. > I've seen the maps, and they are reasonable and complete in both +/-z. > > Jeremy, when you are back at work we can sit and talk... much easier > than trying to explain in email. However, your image (attached) shows > the field ramping up correctly at about Z = -50 cm (in magnet > coordinates, near the target at the right) and abruptly turning off > above approximately Z = +30cm (near layer 5, 70cm downstream of the > target, at the left). Also note that no fringe field is shown at the > downstream end (at the left). This is obviously wrong! I think the > visualization is cutting off at some z, perhaps because at one extreme > in x-y that is the largest z that is in the displayed view. > > Perhaps you need to make some more images to clear this up. > > Tim > > > On Mar 10, 2014, at 7:25 PM, Stepan Stepanyan <[log in to unmask] > <mailto:[log in to unmask]>> wrote: > >> Jeremy, >> >> I think you are showing only field distribution what is in the file, >> which is >> only half plane (X, Z) for Z<=0. If you let me know which files did >> you use >> I can comment on X points. In the field maps points were generated >> for X=0 >> to X=25 cm with steps of 1 cm. In addition, Z=0 for the field map should >> have >> correspond to the center of the magnet, which is not in the picture, I >> think. >> >> In the attachment I am sending a zip file which has field maps for >> central field >> of 5000G. Just want to make sure we are talking about the same maps. >> >> Hope this will help. >> >> Regards, Stepan >> >> On 3/10/14, 7:14 PM, McCormick, Jeremy I. wrote: >>> Hi, Tim/Stepan, >>> >>> What about the field display do you think is wrong vis-a-vis the >>> input field map? >>> >>> I’m in contact with the Geant4 developers on this, so it would be >>> good to know so I can request a fix. Tim, I wasn’t sure what you >>> meant on this. >>> >>> As far as the extent of the field map in -Z, I think that this is >>> something that needs to be done in the conversion from the unfolded >>> single plane set of points to the 3D version. Norman must have that >>> code/script, but I haven’t seen it. This would be good to put into >>> the SVN someplace (sandbox even) so it can be improved. >>> >>> —Jeremy >>> >>> On Mar 10, 2014, at 7:46 AM, Stepan Stepanyan <[log in to unmask] >>> <mailto:[log in to unmask]>> wrote: >>> >>>> Hi TIm, >>>> >>>> Yes, I suspected that it might be a visualization issue. >>>> The reason I was not sure is that I can see the same as you described >>>> about colors and arrows but simply as 1/2 field with Z=0 not at the >>>> center of the magnet. >>>> >>>> Thanks, Stepan >>>> On 3/10/14 10:36 AM, Nelson, Timothy Knight wrote: >>>>> Hi Stepan, >>>>> >>>>> I think the problems at this point are all due to the visual >>>>> representation. Colors and arrow lengths are field strength, red >>>>> being large and green to blue being relatively smaller. I am not >>>>> sure why the field is cut off on the downstream side, but still >>>>> well past z=0, in this image but I'm pretty sure that's a problem >>>>> with the visualization based on the map data I saw that goes into >>>>> this. >>>>> >>>>> Tim >>>>> >>>>> Sent from my iPad >>>>> >>>>>> On Mar 7, 2014, at 8:48 AM, "Stepan Stepanyan" <[log in to unmask] >>>>>> <mailto:[log in to unmask]>> wrote: >>>>>> >>>>>> Hello Jeremy, >>>>>> >>>>>> Thanks for implementing the field. I am not sure how much I >>>>>> should trust >>>>>> the visual picture, but the field you have is generated from the >>>>>> middle of >>>>>> the magnet (in Z), so if I am reading the picture correctly, field is >>>>>> shifted >>>>>> relative to the magnet. For completeness the same (X,+Z) >>>>>> distribution must >>>>>> be repeated for (X,-Z) half plane. >>>>>> One of things we have discussed with Norman some time ago is the need >>>>>> for a full 3-D field map (B_x, B_y, B_z) for (X, Y, Z) points. >>>>>> Will be >>>>>> good to >>>>>> know this early on. >>>>>> >>>>>> Regards, Stepan >>>>>> >>>>>>> On 3/6/14 7:28 PM, McCormick, Jeremy I. wrote: >>>>>>> Hi, >>>>>>> >>>>>>> I made a few fixes to SLIC/LCDD for the support of 3D magnetic >>>>>>> field maps. The map’s offsets were not being set correctly, and >>>>>>> I believe this is now fixed in the HEAD configuration of SLIC in >>>>>>> ilcinstall. >>>>>>> >>>>>>> I also added the missing field data to the SVN at >>>>>>> hps/java/trunk/fieldmap which is referenced by the detector that >>>>>>> includes the field map. >>>>>>> >>>>>>> I was able to get simple visualization working with the >>>>>>> 10.00.p01 release of Geant, and the best picture I have so far >>>>>>> is this: >>>>>>> >>>>>>> http://www.slac.stanford.edu/~jeremym/hps/field/hps_field7.png >>>>>>> <http://www.slac.stanford.edu/%7Ejeremym/hps/field/hps_field7.png> >>>>>>> >>>>>>> This visualization tool is at an “alpha” stage of development in >>>>>>> that project, unfortunately, but it at least gives some idea >>>>>>> that the field has been loaded in successfully. >>>>>>> >>>>>>> That’s the good news. >>>>>>> >>>>>>> The bad news is that the performance is approximately 150x worse >>>>>>> when using the 3D field in a Proposal2014 geometry compared to a >>>>>>> setup with the simplistic fixed dipole. This compares the >>>>>>> HPS-Proposal2014-v5-2pt2 detector with >>>>>>> HPS-Proposal2014-v4-fieldmap using the event file >>>>>>> egs_tri_2.2gev_0.00125x0_200na_5e5b_30mr_001.stdhep. >>>>>>> >>>>>>> So it appears to me this is not really going to be useable in >>>>>>> large scale simulation production until the algorithm for >>>>>>> retrieving and interpolating the field values has been >>>>>>> significantly optimized. >>>>>>> >>>>>>> —Jeremy >>>>>>> ######################################################################## >>>>>>> Use REPLY-ALL to reply to list >>>>>>> >>>>>>> To unsubscribe from the HPS-SOFTWARE list, click the following link: >>>>>>> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1 >>>>>> ######################################################################## >>>>>> Use REPLY-ALL to reply to list >>>>>> >>>>>> To unsubscribe from the HPS-SOFTWARE list, click the following link: >>>>>> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1 >>>>> ######################################################################## >>>>> Use REPLY-ALL to reply to list >>>>> >>>>> To unsubscribe from the HPS-SOFTWARE list, click the following link: >>>>> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1 >> >> <pr_5000.zip> > ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the HPS-SOFTWARE list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1