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Forums > Silicon-package-board > Shared code - SKILL

Subject: Bug with skill lists comparison
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willbi
Posts: 63
Online: User is Offline
5/08/2008 8:28 AM  

I am improving the dangling_lines15_1.il routine.
It worked but I have to treat a job with Bonding.

But with some clines, i fails. I am analysing the code to see what's wrong and I saw a very strange thing (here is a part of the jrl file in attachment).

It first extracts list1 with cline start point coordinates and list2 with cline end point. Then it selects clines within a box with list1/list2 coordinates.
As it selects more than the wanted clines, I wrote a little thing that extracts clineStart list with start point coordinates and clineEnd with end point for each net within selected nets.

Then it compares list1 with clineStart and list2 with clineEnd, if both match, then the cline is the one I need. But it fails.
with
list1=(146.563 -11.0198)
clineStart=(146.563 -11.0198)
list2=(146.563 -11.063)
clineEnd=(146.563 -11.063)
list1==clineStart returns t
list2==clineEnd returns nil!
if I check I found that cadr(list2) < cadr(clineEnd)
So in fact for Skill, -11.063 is less than -11.063!

What to do?

Attachment: list_bug.txt
natebizu
Posts: 7
Online: User is Offline
5/08/2008 8:58 AM  
It looks like you are trying to find connections to a cline. Use axlDBGetConnect, it should save you a lot of time. As for your equallity test, you must check each number of one list to the other using axlGeoEqual.

procedure(GeoEqualPts(pt1 pt2)
axlGeoEqual(car(pt1) car(pt2)) && axlGeoEqual(cadr(pt1) cadr(pt2))
)

GeoEqualPts(list2 clineEnd) ;use instead of line2==clineEnd
Dave Elder
Moderator
Posts: 150
Online: User is Offline
5/08/2008 1:02 PM  
The inequality isn't a "bug" it's a weakness of a combination of floating point binary maths and rounding.
It would rarely be advisable to compare two floating point numbers using absolute equality tests in Allegro or other CAD tools.

Cheers, Dave
Dave Elder
Tait Electronics
redwire
Posts: 73
Online: User is Offline
5/08/2008 11:26 PM  
Question: have you tried the dangling line removal in the gloss routine (lowest level license...)? It works well enough for me that I dropped the SKILL code version.
willbi
Posts: 63
Online: User is Offline
5/19/2008 8:07 AM  
Sorry Dave, I am not mathematician nor a programmer ;-)



I stopped studies rather early.. and I basically surprised to learn that -11.063 is less than -11.063!

As I am autodidact and I learn each, I learned one more thing!



Thanks Natebizu, the function you suggested works great.



redwire: I would prefer the skill I modified and that works now. I tried the gloss, but some of them remain and the routine I modified permits to pass them in review, analyse them (some of them are wanted, some other have to be corrected) and then If all of them can be removed, I added a button to delete all.)
willbi
Posts: 63
Online: User is Offline
5/21/2008 3:56 AM  
If somebody is interested, here is the updated version of dangling_lines15_5 routine. Use at your own risk ;-)

Attachment: dangling_lines15_5.il
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Forums > Silicon-package-board > Shared code - SKILL > Bug with skill lists comparison


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