exxos blog - random goings on

[exxos]

It's basically following my rule of using minimal Vias.. But I think I need to program in a cost algorithm because it's basically doubling the length of track to avoid a Via , where there clearly is room and the tracks literally pass each other !

So probably the rule will be something like over 20mm of track = use a via if possible.

Capture.PNG (73.51 KiB) Viewed 27 times

Also saw it made a similar mistake elsewhere...

2.PNG (18.92 KiB) Viewed 21 times

Writing a autorouter is hard

[mrbombermillzy]

I would have thought that AI probably lacks the spatial visualisation skills needed for this sort of thing.

Although, you seem to be cracking it slowly but surely.

[exxos]

I would have thought that AI probably lacks the spatial visualisation skills needed for this sort of thing.

My girlfriend said exactly the same yesterday

Although, you seem to be cracking it slowly but surely.

Yeah.. But it is still a algorithm based router like all the others are.. AI isn't technically routing the board itself, its writing the algorithms and basically Python scripts are routing the board.

I mean once it has done its corrective passes and tidied the whole thing up, it would have basically beaten my manual routing at that point !

The main problem is it takes several hours just to route a small credit card sized board.. It is 4 layers and two layers are power planes. I think it hit 1GB of RAM usage a few days ago. But the important thing is to get the thing running right then look into ways of making the code a lot more efficient..

Of course this is all just one particular small PCB.. Routing something more complex like the DFB1X from scratch...

[exxos]

About 3.2GB RAM for the whole board now it's got another two hours to complete the optimisation passes I gave it to do but it looks like its doing really well so far.

One track where we basically route to the other way around the board.. I gave it permission to read that on the VCC layer with some exceptions that it doesn't go anywhere near power planes linked to any pads. I haven't given it permission to use VCC layer has a main routing path, only as a optimisation path right at the end. It does not take any significant chunk out of VCC and it saves another via and long routed track.

I have also had to give to very slight hugging bias.

Capture.PNG (90.11 KiB) Not viewed yet

On that image you can clearly see D11 is going around the via as it should. But it has basically has too much gap. This then pushes D3 to the left, and then D10 just goes and does basically the same thing whatever that may be. Which then results in the problem that there isto route D2 anymore. It ends up taking a crazy route upwards instead of going straight down to where another track carries the same signal anyway.The whole thing could have been avoided if the jump around the vias actually "hugged" it closer right at the start.

There is also some other little annoyances like a unnecessary angle in D6,D0,D1 etc when it could be easily straightened out to save angles.

I think Lord is feeling rather smug to itself now as it keeps reminding me how much it has beaten my previous manual rooted board by each pass