IRC log for #brlcad on 20141220

00:14.44 *** join/#brlcad chick_ (~capslock@41.205.22.41)
00:20.50 Notify 03BRL-CAD:starseeker * 63797 brlcad/trunk/src/librt/test_shape_recognition.cpp: Rework the shape recognition test code.
00:22.08 Notify 03BRL-CAD:starseeker * 63798 brlcad/trunk/src/librt/primitives/brep/brep_debug.cpp: Add the ability to use comma-separated lists of elements to the brep's info and plotting commands.
00:42.14 andromeda-galaxy just curious, anyone know why VSETALLN, etc. don't use memset()?
00:50.10 *** join/#brlcad chick_ (~capslock@41.205.22.41)
00:58.19 Stragus First of all, memset() takes a char value, not a float/double/fast_f/whatever
00:59.06 Stragus Next, this macro is being inlined in code, clearing the array with values that the compiler will see clearly and can optimize accordingly
00:59.52 Stragus If you were to memset() with zeroes for example, the compiler won't be able to make proper assumptions to optimize the code. It will end up actually writing to memory, even though values could be kept in registers
01:06.50 ``Erik also; VSETALLN goes back to '94, I don't think c90 compliant compilers were very common in '94
01:09.08 Notify 02GCI:frgnvola * 5213338241859584 : Task Claimed - I would like to work on this task.
01:10.02 Stragus Even today, a compiler will do a better optimization job seeing assignments of 0.0 rather than memset() on an array
01:10.08 Stragus Compilers are pretty stupid overall
01:10.59 Notify 02GCI:erikg * 5213338241859584 : Task Assigned - This task has been assigned to frgnvola. You have 100 hours to complete this task, good luck!
01:11.44 ``Erik depends on how it's handled, some libc "functions" are "magicked" by certain compilers optimizers
01:12.46 ``Erik (I'd be surprised if memset was one of those, though... more for things like atof() and such)
01:12.55 Stragus Yes... I have seen GCC being an idiot for memset() on a small struct
01:14.05 ``Erik Stragus: have you compared gcc vs recent clang at the asm level for "important" things? :) I've not, but clang has grown up very quickly lately
01:14.21 ``Erik be interesting if you had any general insight
01:16.15 Stragus I have some limited experience due to compiling things on OSX with no GCC
01:16.34 Stragus The SSE/AVX support seems poor, clang is doing various stupid things
01:16.43 Stragus In normal C code, it seemed... good
01:17.57 ``Erik sse using intrinsics?
01:18.09 Stragus Yes
01:18.34 ``Erik has never heard anything good about intrinsics in serious performance code with any compiler :/
01:18.45 ``Erik _asm, yo!
01:18.58 Stragus GCC is surprisingly pretty decent
01:19.19 Stragus The actual register allocation is still a disaster, but that's a problem for all compilers
01:20.22 Stragus They need to make compilers which can use branch statistics to plan register allocation properly
01:20.23 ``Erik it seems like register allocation strategies come from two families... x86 and risc, with the x86 forever hindered by the legacy of reserved registers
01:20.53 Stragus A good programmer can easily plan ahead for reserved registers
01:21.35 ``Erik old mips chips had 32 general purpose integer plus 32 floating point registers and compilers could do some pretty awesome painting strategies to do impressive things
01:22.05 ``Erik I don't think the sparc 'register window' stuff was ever really well exploited by compilers, though :/
01:22.13 Stragus 16 and 16 is manageable
01:23.17 Stragus It's terrible to see a compiler flush stuff out of registers, and reload them, because we have some branch in between requiring a bunch of registers... a branch that you know is taken about 1% of the time
01:23.21 Stragus Gah, stupid compilers
01:23.46 Stragus Long ago, I wrote Rayforce pipelines in assembly and they were 30% faster just for managing registers intelligently
01:23.57 andromeda-galaxy Stragus: ah...
01:24.01 ``Erik heheh, but do the x86_64 compilers really think of them as 16+16, or as 4 (not really) gp + 4 reserved plus "others"? I tend to still think of all x86 as "addl means ax<-bx+cx, period... you don't get to choose"
01:24.53 Stragus Compilers tend to think of them as 15+16, then go crazy when faced with an instruction that requires an implicit register
01:25.20 Stragus Going crazy meaning: flush whatever was in rcx, and put our new value there, because we need rcx (or whatever)
01:28.14 andromeda-galaxy speaking of register allocation, I saw an article the other day about integer overflow checking which showed that most of the major compilers allocated registers (on x86 at least) in a very suboptimal way, so that adding overflow decreased the performance by ~6x instead of the <2x that would be expected...
01:29.25 Stragus Right. Detecting integer overflow, in assembly, is just checking the value of a flag after the "add". You can jump or "set" a value from that flag, and act accordingly
01:30.19 Stragus For such simple things, which may seem totally fundamental, you end up needing assembly
01:32.00 ``Erik some archs even had interrupt vector traps on overflow, so 0 overhead until an overflow occured, then custom code could be run to "deal with it" (like automatically promoting types and trying again)... those were neat
01:32.50 Stragus Hum... I assume you had variants of the instructions that would not trigger overflow interrupts
01:32.56 ``Erik leans forward in his rocking chair and shakes his cane
01:33.05 Stragus You don't really want an interrupt because your "add" overflows in cryptology
01:33.33 ``Erik I didn't use those archs, read about them in passing... I think the symbolics machines did it
01:34.41 Stragus Also, it seems harder to manage the overflow in an interrupt handler than in code
01:35.00 ``Erik but that kinda sounds like abusing a misfeature that could be done with bitwise ops
01:37.03 Stragus Many (all?) cryptography algorithms demand two-complement add/sub, with top bits discarded
01:37.24 Stragus But an overflow interrupt is fine as long as it's optional :)
01:40.06 ``Erik I d'no about the symbolics machines, but I THINK old accumulator machines (like mos65xx, cuz I'm old) let you set an 'ignore' value in an interrupt slot, so you could opt out of catching it and just let the program continue
01:40.50 ``Erik I guess you could make a handler that just returned, too
01:40.53 Stragus Throw that cane already, you aren't that old :)
01:41.11 ``Erik "ohs noes, overflow! help us, trap!" "nah, dude, it's all good, carry on"
01:42.56 Stragus I think I once read some story about a rocket that exploded during launch due to a code error, because the wrong variant of the "add" instruction was used somewhere, triggering an interrupt on overflow
01:43.13 Stragus For code that was related to rocket positionning on the launch pad that they had forgotten to turn off
01:43.30 ``Erik heh, woops :) that's an expensive oversight
01:44.27 ``Erik speaking of rockets exploding, that one that exploded a few weeks ago in virginia was a bummer, I was standing outside waiting for it to clear the horizon :(
01:46.00 Stragus I was watching online :(
01:46.10 ``Erik ok, maybe almost 2 months ago, oct28
01:46.35 ``Erik was in the t+90 visibility range
01:46.39 Stragus So much for refurbished soviet engines
01:47.40 Stragus I think I read that they had two engine "failures" (blowing up) in ground testing in the past year
01:47.49 ``Erik well, the had a couple good launches with those engines before... but 50 year old gear from a country that was pretty accepting of accidents... *shrug*
01:50.22 Stragus At least the Orion launcher is doing pretty good. To Mars! (?..)
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02:02.01 andromeda-galaxy regress_repository fails on files that don't include common.h first, even when they don't actually need anything in it and so don't include it at all... is that intentional?
02:04.06 Notify 02GCI:adityagulati * 5863782450462720 : Task Claimed - I would like to work on this task.
02:06.03 Notify 02GCI:o7p9bxbnyj * 5283618133901312 : Ready for review - The work on this task is ready to be reviewed.
02:06.39 Stragus There, ``Erik, this is the rocket that your integer overflow interrupt destroyed: http://en.wikipedia.org/wiki/Cluster_%28spacecraft%29
02:08.54 Stragus Software should be designed with the Apple OS Classic philosophy in mind: make the page zero writable by all processes, so that no software will crash for using a null pointer
02:08.58 Stragus *cough*
02:10.10 Notify 03BRL-CAD Wiki:Ssfrgnvola * 7842 /wiki/Talk:Main_page:
02:27.35 Stragus The more complete story for that rocket failure: http://www.around.com/ariane.html
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03:15.01 Notify 02GCI:brlcad * 4531831353376768 : horse source - Shakthi, Did you draw that horse? You should always cite your sources and give credit to others if you utilize the works of others. This is a...
03:15.02 Notify 02GCI:brlcad * 4531831353376768 : Task Needs More Work - One of the mentors has sent this task back for more work. Talk to the mentor(s) assigned to this task to satisfy the requirements needed to...
03:15.41 Notify 02GCI:brlcad * 5283618133901312 : Task Closed - Congratulations, this task has been completed successfully.
03:16.16 Notify 02GCI:brlcad * 5283618133901312 : doing a great job - Doing a great job avoiding/minimizing the use of globals.
03:16.56 Notify 02GCI:brlcad * 5857438834098176 : Task Needs More Work - One of the mentors has sent this task back for more work. Talk to the mentor(s) assigned to this task to satisfy the requirements needed to...
03:17.51 Notify 02GCI:o7p9bxbnyj * 5772509429366784 : Task Claimed - I would like to work on this task.
03:23.21 Notify 02GCI:brlcad * 5857438834098176 : unintentional connotation - Jude, this design is a little awkward with the face (makes it seem unprofessional) ... almost creepy! :) That said, the bigger issue...
03:23.51 Notify 02GCI:brlcad * 5863782450462720 : Task Assigned - This task has been assigned to Aditya Gulati. You have 100 hours to complete this task, good luck!
03:29.17 Notify 02GCI:brlcad * 5900674122383360 : Task Needs More Work - One of the mentors has sent this task back for more work. Talk to the mentor(s) assigned to this task to satisfy the requirements needed to...
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03:43.09 Notify 02GCI:brlcad * 5900674122383360 : constructors - 1. Those are five different constructors, so yes you should end up testing each of those constructor methods (either directly or indirectly). If the...
03:43.49 Notify 02GCI:brlcad * 5772509429366784 : Task Assigned - This task has been assigned to Andromeda Galaxy. You have 100 hours to complete this task, good luck!
04:05.09 starseeker andromeda-galaxy: the general rule for our sources is to always lead off with common.h - ensures uniformity on some things
04:05.53 Notify 03BRL-CAD:starseeker * 63799 (brlcad/trunk/src/librt/CMakeLists.txt brlcad/trunk/src/librt/test_shape_recognition.cpp): don't add -1 edges
04:06.36 Notify 03BRL-CAD:starseeker * 63800 brlcad/trunk/src/librt/CMakeLists.txt: keep test off by default
04:34.06 *** join/#brlcad YashM (~YashM@59.88.30.76)
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05:14.57 *** join/#brlcad bjrohan (~bjrohan@70-59-134-53.ptld.qwest.net)
05:15.53 bjrohan Hello all. New to brlcad, but not new to CAD/CAM. I am trying to open an iges file. I start brlcad, open the file, but nothing appears to happen, how can I tell what did work?
05:18.53 YashM iges-g file.iges > file.g
05:19.23 bjrohan ?
05:19.43 YashM go to BRLCAD bin
05:19.57 YashM there should be a iges-g.exe
05:20.14 bjrohan ok
05:20.40 bjrohan I am using it on Ubuntu, what would I be looking for?
05:20.47 YashM iges-g
05:21.05 YashM just open terminal there and try iges-g file.iges > file.g
05:25.29 bjrohan It gave me a usage list
05:25.51 bjrohan I'm ot sure which option I should use
05:26.07 bjrohan Here is what I entered in the terminal: iges-g Stratos_Spacer.IGS > Stratos_Spacer.g
05:26.41 bjrohan I do now have a Stratos_Spacer.g
05:27.35 bjrohan Opening it doesn't show anything
05:28.12 YashM theres those parameters, see what you want it to do and put those parameters
05:30.57 bjrohan I don't know what I want it to do :-/
05:31.33 YashM iges-g [-N solid_name] [-X nmg_debug_flag] [-x rt_debug_flag] [-n|d|t] -o file.g file.iges
05:31.40 YashM use this format
05:32.25 YashM put something in -N, -X, -x
05:32.48 YashM and theres specifications for -n or -d or -t, so see what each does
05:33.02 YashM -o stays where it is
05:33.12 YashM and replace name of your file
05:33.14 YashM in the last
05:34.44 bjrohan My original file name is Stratos_Spacer.IGS, what do you recommend?
05:34.50 bjrohan for the debug
05:35.20 YashM I am not sure, try giving some name
05:37.57 bjrohan something like iges-g -N Stratos_Spacer.IGS -X nmg_debug -x rt_debug -o Stratos_Spacer.g
05:38.05 bjrohan not sure what you mean by the last file name
05:38.49 YashM iges-g -N Stratos_Spacer -X nmg_debug -x rt_debug -n -o Stratos_Spacer.g Stratos_Spacer.IGS
05:38.53 YashM try this
05:39.14 *** join/#brlcad ignacio (~IgnacioUy@unaffiliated/ignaciouy)
05:40.59 bjrohan YashM: Here is the return: http://paste.ubuntu.com/9576842/
05:42.22 bjrohan the .g file is all of 8.8kb whereas the original igs file is 474.9
05:43.07 YashM iges-g -d -o file.g Stratos_Spacer.IGS
05:43.10 YashM try thi
05:43.25 YashM also open the .g and see what comes
05:44.04 bjrohan Open the .g now, or after the new command?
05:44.19 YashM both
05:45.12 YashM This IGES file contains drawing entities, This IGES file contains trimmed surfaces
05:46.12 bjrohan Neither open in brlcad
05:46.50 bjrohan Well, at least nothing appears, it doesn't say it can't open either file. When I open, it gives the model name, and the units
05:46.53 bjrohan but no model
05:47.04 YashM double click it
05:48.21 bjrohan the file?
05:48.27 YashM the modedl name
05:48.33 bjrohan ok
05:50.43 bjrohan Ahh, in the file.g there was nothing listed in the Tree, in the Stratos_Spacer.g it was named in the tree (I didn't see it before), and selecting it shows a model, but it doesn't come close to looking like the IGS should looke like (I can open it in FreeCAD, but I can manipulate or take accurate measurements)
05:53.30 YashM <PROTECTED>
05:53.37 YashM iges-g -N Stratos_Spacer -X nmg_debug -x rt_debug -t -o Stratos_Spacer.g Stratos_Spacer.IGS
05:53.44 YashM try these 2
05:57.04 bjrohan Neither results in anything appearin in the brlcad tree as before
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05:58.15 bjrohan YashM: Here is the output from the 1st line above: http://paste.ubuntu.com/9576929/
05:59.28 bjrohan YashM: The result of the 2nd line: http://paste.ubuntu.com/9576934/
06:00.01 YashM did u run all 3 cmds in the same file name
06:00.38 bjrohan The same original IGS file name yes
06:00.54 bjrohan I copied ans pasted each line, then opened it in blrcad
06:00.59 bjrohan the .g file
06:01.35 YashM same .g file name?
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06:02.20 bjrohan In brlcad i ran a line, then tried to open Stratos_Spacer.g to see the result
06:02.24 bjrohan then ran the 2nd
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06:08.45 ignacio Good night everyone !! :)
06:08.47 *** join/#brlcad FreezingCold (~FreezingC@135.0.41.14)
06:11.49 YashM bjrohan, you might want to wait for a mentor
06:12.42 bjrohan YashM: Thank you :-)
06:20.12 bjrohan YashM: Anyone that I should keep en eye out for?
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07:28.07 MarcWindows brlccad, you around?
07:28.17 MarcWindows andrei and rossberg are not here and I want to ask you something about what you said in the comments
07:28.41 MarcWindows you mentioned the height being Vector3D because it needs a direction as well as a number, but wouldn't that make it a Vector2D?
07:31.26 MarcWindows Oh my god
07:31.37 MarcWindows The guy who runs css-tricks.com just hearted my animation :O
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08:56.19 Stragus just bought a 100 trillion dollars Zimbabwe note on eBay, eh
09:00.00 YashM for how much
09:02.00 Stragus $18. It was going for $5 not long ago, I should have acted sooner
09:02.18 Stragus Also because it would have made a nice joke as a Christmas present :)
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09:57.04 Notify 02GCI:tannousmarc * 5900674122383360 : Ready for review - The work on this task is ready to be reviewed.
09:57.47 Notify 02GCI:tannousmarc * 5900674122383360 : Why so much code? - Because it tests pretty much all possible Cone constructors, as set and clone have to have 5 functions each for each type of cone. ...
10:02.39 Notify 02GCI:Melange * 6662339411574784 : Task Reopened - Melange has detected that the final deadline has passed and it has reopened the task.
10:14.20 Notify 02GCI:rishisharma7361 * 5779545307217920 : Ready for review - The work on this task is ready to be reviewed.
10:20.18 Notify 02GCI:rishisharma7361 * 5779545307217920 : Ready for review - The work on this task is ready to be reviewed.
10:31.34 Notify 02GCI:gjeet * 5779545307217920 : None - Hey rishi, it's better, here are my thoughts on your design. The two sided BRL-CAD logo looks a bit odd in your design. I would suggest to do something...
10:31.40 Notify 02GCI:gjeet * 5779545307217920 : Task Needs More Work - One of the mentors has sent this task back for more work. Talk to the mentor(s) assigned to this task to satisfy the requirements needed to...
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11:54.12 YashM tomorrow is the 10th BRL-CAD open source anniversary
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12:30.09 Notify 02GCI:Melange * 5042004748664832 : Task Reopened - Melange has detected that the final deadline has passed and it has reopened the task.
12:33.12 ignacio hi all, good morning :)
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13:12.56 ashank hello sir,i want to contribute to this
13:14.17 YashM hi ashank
13:14.33 Notify 02GCI:Melange * 5845550716944384 : Task Reopened - Melange has detected that the final deadline has passed and it has reopened the task.
13:14.48 ashank hi yash
13:15.11 ashank so i found "fix buges" under "performance & quality" in idea page,but dont know how to approach
13:18.05 ashank can you please help me ?
13:18.15 YashM in where?
13:18.38 YashM where did you find that
13:19.05 ashank http://brlcad.org/wiki/Google_Summer_of_Code/Project_Ideas#Mentors
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14:06.33 ashank you can check it
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14:22.09 ashank__ @yash!-plz tell me how to start?
14:23.11 YashM Isn't it too early for GSoC?
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14:39.10 Notify 02GCI:helix * 5823454855036928 : Claim Removed - The claim on this task has been removed, someone else can claim it now.
14:39.15 Notify 02GCI:helix * 6661010656067584 : Task Claimed - I would like to work on this task.
14:46.48 starseeker bjrohan: our iges importer needs some work - even if it did bring in the geometry, right now it's using an old representation internally
14:47.06 starseeker bjrohan: can you export from FreeCAD using step?
14:47.12 starseeker (ideally, STEP AP203)
14:47.39 starseeker if so, step-g -o file.g file.step might have better luck
15:10.47 starseeker maths22: is there anything we can do to help with the buildbot/CDash setup and configuration?
15:11.31 starseeker is our biggest need at this point build clients?
15:21.27 Notify 02GCI:deno * 4956557716488192 : Task Claimed - I would like to work on this task.
15:23.22 Notify 02GCI:rishisharma7361 * 5779545307217920 : Work Uploaded - I have kept it simple. I used the picture from BRL-CAD's site and written MOOSE with BRL-CAD's logo
15:23.32 Notify 02GCI:rishisharma7361 * 5779545307217920 : Ready for review - The work on this task is ready to be reviewed.
15:23.52 Notify 02GCI:deno * 4956557716488192 : Claim Removed - The claim on this task has been removed, someone else can claim it now.
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