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CNTK_2_0_Beta_7_Release_Notes

Allison Brucker (Resources Online) edited this page May 30, 2017 · 3 revisions

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CNTK v.2.0 Beta 7 Release Notes

This is a summary of new features delivered with the Beta 7 release of CNTK V.2.0.

Python API

In the past, the Python API was very permissive in what it accepted as data input types. This caused a lot of confusion (e.g. non-sequence data being wrongly then interpreted as sequences). Therefore we have made the Python API stricter. In particular:

  • Sequences now have to be provided as single NumPy or Scipy sparse arrays. I.e., it is not any more allowed to provide a sequence as a list of NumPy arrays or Scipy sparse arrays.
  • The helper function cntk_device has been hidden in the testing modules. For device selection use the module cntk.device
  • Python default initialization is set to normal (std=1) and uniform ([-1,1]).
  • gaussian is renamed to normal.

New Examples and Tutorials

We have prepared the following Examples and Tutorials:

C++ / Backend

We have made some changes and improvements in CNTK Backend:

  • Changed data distribution in multi-GPU training for the composite reader in the frame mode
  • Improved performance in the composite reader to use all available CPU threads during deserialization/transformation
  • Random number generator and distributions were updated at many places to be the same across supported platforms (Linux and Windows)
    • Backward compatibility note: training (in particular initialization) may not be exactly reproducible with respect to the previous versions
  • Implemented an optimization to elide the initial zeroing and subsequent accumulation into the gradients for nodes with just one parent/ancestor node

CNTK Evaluation library. NuGet package

A new Nuget package with the latest eval DLL (managed and native) is available.

IMPORTANT! In Visual Studio Manage Nuget Packages Window change the default option Stable Only to Include Prerelease. Otherwise the package will not be visible. The Package version should be 2.0-beta7.

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