Highlights

• Added Platform LSF and jsrun support to horovodrun. (#1805)
• Added support for running Horovod on Spark with Gloo in place of MPI. (#1807)
• Added synchronous batch normalization for horovod.torch API. (#1923)

Additional changes

• Added support for providing a set of inclusive NICs to horovodrun. (#1808)
• Added optional initial_lr parameter to LearningRateScheduleCallback, deprecated implicit initialization. (#1933)
• Changed Spark Estimators to use Petastorm BatchDataLoader. (#1879)
• Changed Spark Estimators to use Petastorm's make_reader API. (#1804)
• Improved latency of background thread loop. (#1880)
• Enabled setting Horovod background thread affinity with all frameworks. (#1881)
• Added verbose parameter to SparkBackend. (#1922)
• Use parameter names when scheduling broadcasts in MXNet broadcast_parameters. (#1894)
• Added metadata cache with calling fit_on_parquet. (#1826)
• Added optional local version to package version. (#1925)

Bugfixes

• Fixed module resolution for tf.keras optimizers when calling hvd.load_model. (#1935)
• Modified safe_shell_exec to use multiprocessing spawn instead of fork to prevent deadlocks. (#1915)
• Fixed multiprocessing to support Python 3.8. (#1904)
• Added extra preprocessor guard for FMA optimization. (#1835)
• Fixed exception in KerasEstimator when num_proc is larger than 4. (#1945)
• Fixed memory leaks. (#1845)
• Fixed a bug with sample weight in TorchEstimator. (#1790)
• Removed torchvision from pytorch extra. (#1899)