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CNTK v.2.0 RC 2 Release Notes

  • Article

With the Release Candidate 2 we ship one of the last previews before the Microsoft Cognitive Toolkit V2 final release by the end of May. There is still time to incorporate your feedback - so keep it coming!

CNTK Core: new and improved features

  • New operators added: pow, sequence.reduce_max, and sequence.softmax.
  • New feature for Linux source builds:
    • GPU Direct RDMA support in distributed gradients aggregation (enabled through ./configure --gdr=yes).
    • NCCL support for Python in V2 gradients aggregation
  • Additional bug fixes and improvements, including:
    • Added functionality to set and get global tracing verbosity level.
    • Added a mechanism to preserve the local state of a distributed worker in the checkpoint.
    • The initial random seed can now be specified for dropout and random sample nodes, the auto-generated seed values for these nodes are now worker-specific.
    • Progress writers will log changes in learning rates and momentum values.

CNTK Python API

New and improved features

  • Support for Python 3.6 for source and binary installation; see setup instructions.
  • UserMinibatchSource now allows to write custom minibatch sources and pass them to the CNTK core. See here for documentation.
  • CNTK deterministic mode (cntk.cntk_py.force_deterministic_algorithms()) can be enabled in all configurations, except for overlapped max pooling.
  • Training session switched to distributed test evaluation and cross validation.

CNTK C#/.NET Managed API

New and improved features

  • New APIs: class NDArrayView and methods, SetMaxNumCPUThreads(), GetMaxNumCPUThreads(), SetTraceLevel(), GetTraceLevel()
  • Memory and performance optimization.

The updated APIs are described here.

CNTK NuGet package

A new set of NuGet Packages is provided with this Release.

IMPORTANT! For Visual Studio: In the Manage NuGet Packages window change the default option Stable Only to Include Prerelease. Otherwise the release candidate package of CNTK will not be visible. This Package version is 2.0.0-rc2.