v0.4.0a2

This is the release notes of v0.4.0a2. See here for the complete list of solved issues and merged PRs.

New Features

• Tensor:
  • Add ability to read and write HDF5 file for tensor (#962)
  • Implements mt.{topk, argsort, argpartition, argtopk} (#946)
  • Support reading and writing in zarr format (#963)
  • Implement imread to read from images (#988)
• DataFrame
  • Support ufunc for Mars DataFrame (#957)
  • Implements DataFrame.to_csv (#966)
  • Implement dataframe var and std (#977)
  • Implements Series.map (#979)
  • Implements DataFrame dot, mul and pow (#980)
  • Implements describe for DataFrame (#981)
  • Implements md.read_sql_table (#986)
• Learn
  • Implement PyTorch sampler to improve dataset performance (#970)
  • Support mars.learn.neighbors.NearestNeighbors (#961)
  • Leverage faiss to accelerate k-nearest neighbors calculation (#984)
  • Implement pytorch sampler for local training (#1010)

Enhancements

• Refactor tensor indexing (#1011)

Bug fixes

• Fix tile in nonzero that tensor instead of tensor data should be used during the process (#954)
• Fixes cdist(x, y) that creates tensor with wrong nsplits (#960)
• Fix the wrong RangeIndex in read_csv (#930)
• Stop detecting GPU when no cuda devices are configured (#973)
• Fix wrong behavior of mt.random.choice (#976)
• Make sure all kwargs are numpy types when inferring dtypes (#987)
• Fix error when chunk_size not provided for md.read_sql_table (#990)
• Fix wrong result of count_nonzero (#1002)
• Add dtype property for TensorImread (#1004)
• Fix error when no device detected by CUDA driver (#1007)

Tests

• Fix failed unittests due to release of pandas 1.0 (#964)
• Hotfix opcodes that conflict (#968)