Distributed training with PyTorch: PointPillars on Waymo

[sanskar107]

Added support for distributed training for PyTorch ObjectDetection pipeine.

• [x] Modify launch script to spawn multiple process for multi-gpu training.
• [x] Update Object Detection Pipeline to support multiple gpus.
• [x] Train PointPillars on large scale datasets like Waymo.
• [ ] Train PointRCNN on Waymo.
• [ ] Update Semantic Segmentation pipeiine to support multi-gpu. (Update RandLANet and KPConv to avoid using samplers in dataloaders)
• [ ] Train Semantic Segmentation models.

Some Results: [Vehicle] green : ground truth [Vehicle] orange: prediction

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This change is 

[lgtm-com[bot]]

This pull request introduces 2 alerts when merging 306de5bda59be3b0bd6c834b883faf734adf054e into 2b86a838b5e10a202cc6cc9e5fbcbda27aa2dd73 - view on LGTM.com

new alerts:

• 2 for Unused import

[lgtm-com[bot]]

This pull request introduces 1 alert when merging b953254ef12023b33864639cb9532a624a84fc09 into bbac251d419b485f9eb770b8c39b8e44194efd80 - view on LGTM.com

new alerts:

• 1 for Unused import

[lgtm-com[bot]]

This pull request introduces 1 alert when merging 27793394385d2deab2e618fde904a63828080f7b into bbac251d419b485f9eb770b8c39b8e44194efd80 - view on LGTM.com

new alerts:

• 1 for Unused import

[lgtm-com[bot]]

This pull request introduces 1 alert when merging 53479c2838abce31cf832a3ba441fd9332ca6570 into a371cae9f417277aae28c02dd870f31ac5349f6b - view on LGTM.com

new alerts:

• 1 for Unused import

[lgtm-com[bot]]

This pull request introduces 1 alert when merging 6139e66449f559f0f7ffe33bfb6d37a580c2cb18 into 203b8c6955c772bbac8f971163e181d2e4a12e39 - view on LGTM.com

new alerts:

• 1 for Unused import

[lgtm-com[bot]]

This pull request introduces 4 alerts when merging d9e156488d53f55d7894f404185d478e4b0ddf54 into 5baf7223e9126e26feffc6f08d4b9ae728367dd1 - view on LGTM.com

new alerts:

• 3 for Unused import
• 1 for Unused local variable

[lgtm-com[bot]]

This pull request introduces 3 alerts when merging ef0e44053adfc7ddaddd25b7f78513d653dbca30 into 5baf7223e9126e26feffc6f08d4b9ae728367dd1 - view on LGTM.com

new alerts:

• 2 for Unused import
• 1 for Unused local variable

[lgtm-com[bot]]

This pull request introduces 3 alerts when merging 10164f9437df7057b36b8ad49ff427e9660934d8 into 8ddb67206e4fef55b39eea691ff00d49cef18be5 - view on LGTM.com

new alerts:

• 1 for Use of the return value of a procedure
• 1 for Unused local variable
• 1 for Unused import

[lgtm-com[bot]]

This pull request introduces 3 alerts when merging 6d58cd12faee716feb0385dd020e3e85880d1ae1 into 8ddb67206e4fef55b39eea691ff00d49cef18be5 - view on LGTM.com

new alerts:

• 1 for Use of the return value of a procedure
• 1 for Unused local variable
• 1 for Unused import

[lgtm-com[bot]]

This pull request introduces 1 alert when merging 51a16c376259ab7d4410e4f4590a2a1090b55bb7 into 8ddb67206e4fef55b39eea691ff00d49cef18be5 - view on LGTM.com

new alerts:

• 1 for Use of the return value of a procedure

[lgtm-com[bot]]

This pull request introduces 2 alerts and fixes 6 when merging 1ed11c8841bbb4423dc82f553a4029c03fcec66e into 8ddb67206e4fef55b39eea691ff00d49cef18be5 - view on LGTM.com

new alerts:

• 1 for Use of the return value of a procedure
• 1 for Unused import

fixed alerts:

• 4 for Unused local variable
• 2 for Unused import

[lgtm-com[bot]]

This pull request introduces 2 alerts and fixes 6 when merging eb3b5518e6fc4a4e0d531da1905afc773d041d19 into 8ddb67206e4fef55b39eea691ff00d49cef18be5 - view on LGTM.com

new alerts:

• 1 for Use of the return value of a procedure
• 1 for Unused import

fixed alerts:

• 4 for Unused local variable
• 2 for Unused import

[lgtm-com[bot]]

This pull request introduces 2 alerts and fixes 6 when merging e49f4ecfe6c7bdb83634613d64cb247b5bcf6b0e into c581efe41328653817546f94fcac772264ec3b42 - view on LGTM.com

new alerts:

• 1 for Use of the return value of a procedure
• 1 for Unused import

fixed alerts:

• 4 for Unused local variable
• 2 for Unused import