Function build_lr_scheduler

detectron2/solver/build.py:198–223

Build a LR scheduler from config.

(
    cfg: CfgNode, optimizer: torch.optim.Optimizer
)

def build_lr_scheduler(
    cfg: CfgNode, optimizer: torch.optim.Optimizer
) -> torch.optim.lr_scheduler._LRScheduler:
    """
    Build a LR scheduler from config.
    """
    name = cfg.SOLVER.LR_SCHEDULER_NAME
    if name == "WarmupMultiStepLR":
        return WarmupMultiStepLR(
            optimizer,
            cfg.SOLVER.STEPS,
            cfg.SOLVER.GAMMA,
            warmup_factor=cfg.SOLVER.WARMUP_FACTOR,
            warmup_iters=cfg.SOLVER.WARMUP_ITERS,
            warmup_method=cfg.SOLVER.WARMUP_METHOD,
        )
    elif name == "WarmupCosineLR":
        return WarmupCosineLR(
            optimizer,
            cfg.SOLVER.MAX_ITER,
            warmup_factor=cfg.SOLVER.WARMUP_FACTOR,
            warmup_iters=cfg.SOLVER.WARMUP_ITERS,
            warmup_method=cfg.SOLVER.WARMUP_METHOD,
        )
    else:
        raise ValueError("Unknown LR scheduler: {}".format(name))