Nvtext Minhash

group nvtext_minhash

Functions

std::unique_ptr<cudf::column> minhash(cudf::strings_column_view const &input, cudf::numeric_scalar<uint32_t> seed = 0, cudf::size_type width = 4, rmm::cuda_stream_view stream = cudf::get_default_stream(), rmm::mr::device_memory_resource *mr = rmm::mr::get_current_device_resource())

Returns the minhash value for each string.

Hash values are computed from substrings of each string and the minimum hash value is returned for each string.

Any null row entries result in corresponding null output rows.

This function uses MurmurHash3_x86_32 for the hash algorithm.

Throws:

std::invalid_argument – if the width < 2

Parameters:

• input – Strings column to compute minhash

• seed – Seed value used for the hash algorithm

• width – The character width used for apply substrings; Default is 4 characters.

• stream – CUDA stream used for device memory operations and kernel launches

• mr – Device memory resource used to allocate the returned column’s device memory

Returns:

Minhash values for each string in input

std::unique_ptr<cudf::column> minhash(cudf::strings_column_view const &input, cudf::device_span<uint32_t const> seeds, cudf::size_type width = 4, rmm::cuda_stream_view stream = cudf::get_default_stream(), rmm::mr::device_memory_resource *mr = rmm::mr::get_current_device_resource())

Returns the minhash values for each string per seed.

Hash values are computed from substrings of each string and the minimum hash value is returned for each string for each seed. Each row of the list column are seed results for the corresponding string. The order of the elements in each row match the order of the seeds provided in the seeds parameter.

This function uses MurmurHash3_x86_32 for the hash algorithm.

Any null row entries result in corresponding null output rows.

Throws:

• std::invalid_argument – if the width < 2

• std::invalid_argument – if seeds is empty

• std::overflow_error – if seeds * input.size() exceeds the column size limit

Parameters:

• input – Strings column to compute minhash

• seeds – Seed values used for the hash algorithm

• width – The character width used for apply substrings; Default is 4 characters.

• stream – CUDA stream used for device memory operations and kernel launches

• mr – Device memory resource used to allocate the returned column’s device memory

Returns:

List column of minhash values for each string per seed

std::unique_ptr<cudf::column> minhash64(cudf::strings_column_view const &input, cudf::numeric_scalar<uint64_t> seed = 0, cudf::size_type width = 4, rmm::cuda_stream_view stream = cudf::get_default_stream(), rmm::mr::device_memory_resource *mr = rmm::mr::get_current_device_resource())

Returns the minhash value for each string.

Hash values are computed from substrings of each string and the minimum hash value is returned for each string.

Any null row entries result in corresponding null output rows.

This function uses MurmurHash3_x64_128 for the hash algorithm. The hash function returns 2 uint64 values but only the first value is used with the minhash calculation.

Throws:

std::invalid_argument – if the width < 2

Parameters:

• input – Strings column to compute minhash

• seed – Seed value used for the hash algorithm

• width – The character width used for apply substrings; Default is 4 characters.

• stream – CUDA stream used for device memory operations and kernel launches

• mr – Device memory resource used to allocate the returned column’s device memory

Returns:

Minhash values as UINT64 for each string in input

std::unique_ptr<cudf::column> minhash64(cudf::strings_column_view const &input, cudf::device_span<uint64_t const> seeds, cudf::size_type width = 4, rmm::cuda_stream_view stream = cudf::get_default_stream(), rmm::mr::device_memory_resource *mr = rmm::mr::get_current_device_resource())

Returns the minhash values for each string per seed.

Hash values are computed from substrings of each string and the minimum hash value is returned for each string for each seed. Each row of the list column are seed results for the corresponding string. The order of the elements in each row match the order of the seeds provided in the seeds parameter.

This function uses MurmurHash3_x64_128 for the hash algorithm.

Any null row entries result in corresponding null output rows.

Throws:

• std::invalid_argument – if the width < 2

• std::invalid_argument – if seeds is empty

• std::overflow_error – if seeds * input.size() exceeds the column size limit

Parameters:

• input – Strings column to compute minhash

• seeds – Seed values used for the hash algorithm

• width – The character width used for apply substrings; Default is 4 characters.

• stream – CUDA stream used for device memory operations and kernel launches

• mr – Device memory resource used to allocate the returned column’s device memory

Returns:

List column of minhash values for each string per seed