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rachelselinar / DREAMPlaceFPGA

An Open-Source Analytical Placer for Large Scale Heterogeneous FPGAs using Deep-Learning Toolkit
BSD 3-Clause "New" or "Revised" License
65 stars 18 forks source link

Always one instance being placed to "1 0 15" #5

Closed zhilix closed 1 year ago

zhilix commented 1 year ago

When I run global placement and legalization for gnl designs and FPGA-example designs, in the final solution there is always one instrance being placed to "1 0 15".

Screen Shot 2023-03-03 at 20 13 58 PM

Screen Shot 2023-03-04 at 23 18 27 PM

which is very far away from other instances being placed in the center of the layout.

I tried to dump out placement solutions at different stages and found probably something happened during "ripUP_Greedy_slotAssign".

rachelselinar commented 1 year ago

Thanks for catching this corner case bug when an instance has only 1 ripUp candidate during legalization. Fix is in to include a check to ensure the instance is legalized during ripUP LG stage, if not it is legalized in a greedy manner. There are no issues with the large ISPD'16 benchmarks FPGA01-FPGA12. Closing issue.