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::device_async_resource_ref mr = cudf::get_current_device_resource_ref())#

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.

Deprecated:

Deprecated in 24.12

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::device_async_resource_ref mr = cudf::get_current_device_resource_ref())#

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.

Deprecated:

Deprecated in 24.12 - to be replaced in a future release

Throws:

  • std::invalid_argument – if the width < 2

  • std::invalid_argument – if seeds is empty

  • std::overflow_error – if seeds.size() * 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> minhash_permuted(cudf::strings_column_view const &input, uint32_t seed, cudf::device_span<uint32_t const> parameter_a, cudf::device_span<uint32_t const> parameter_b, cudf::size_type width, rmm::cuda_stream_view stream = cudf::get_default_stream(), rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref())#

Returns the minhash values for each string.

This function uses MurmurHash3_x86_32 for the hash algorithm.

The input strings are first hashed using the given seed over substrings of width characters. These hash values are then combined with the a and b parameter values using the following formula: 

max_hash = max of uint32
mp = (1 << 61) - 1
hv[i] = hash value of a substring at i
pv[i] = ((hv[i] * a[i] + b[i]) % mp) & max_hash

This calculation is performed on each substring and the minimum value is computed as follows: 

mh[j,i] = min(pv[i]) for all substrings in row j
                     and where i=[0,a.size())

Any null row entries result in corresponding null output rows.

Throws:

  • std::invalid_argument – if the width < 2

  • std::invalid_argument – if parameter_a is empty

  • std::invalid_argument – if parameter_b.size() != parameter_a.size()

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

Parameters:

  • input – Strings column to compute minhash

  • seed – Seed value used for the hash algorithm

  • parameter_a – Values used for the permuted calculation

  • parameter_b – Values used for the permuted calculation

  • width – The character width of substrings to hash for each row

  • 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::device_async_resource_ref mr = cudf::get_current_device_resource_ref())#

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.

Deprecated:

Deprecated in 24.12

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::device_async_resource_ref mr = cudf::get_current_device_resource_ref())#

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.

Deprecated:

Deprecated in 24.12 - to be replaced in a future release

Throws:

  • std::invalid_argument – if the width < 2

  • std::invalid_argument – if seeds is empty

  • std::overflow_error – if seeds.size() * 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_permuted(cudf::strings_column_view const &input, uint64_t seed, cudf::device_span<uint64_t const> parameter_a, cudf::device_span<uint64_t const> parameter_b, cudf::size_type width, rmm::cuda_stream_view stream = cudf::get_default_stream(), rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref())#

Returns the minhash values for each string.

This function uses MurmurHash3_x64_128 for the hash algorithm.

The input strings are first hashed using the given seed over substrings of width characters. These hash values are then combined with the a and b parameter values using the following formula: 

max_hash = max of uint64
mp = (1 << 61) - 1
hv[i] = hash value of a substring at i
pv[i] = ((hv[i] * a[i] + b[i]) % mp) & max_hash

This calculation is performed on each substring and the minimum value is computed as follows: 

mh[j,i] = min(pv[i]) for all substrings in row j
                     and where i=[0,a.size())

Any null row entries result in corresponding null output rows.

Throws:

  • std::invalid_argument – if the width < 2

  • std::invalid_argument – if parameter_a is empty

  • std::invalid_argument – if parameter_b.size() != parameter_a.size()

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

Parameters:

  • input – Strings column to compute minhash

  • seed – Seed value used for the hash algorithm

  • parameter_a – Values used for the permuted calculation

  • parameter_b – Values used for the permuted calculation

  • width – The character width of substrings to hash for each row

  • 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> word_minhash(cudf::lists_column_view const &input, cudf::device_span<uint32_t const> seeds, rmm::cuda_stream_view stream = cudf::get_default_stream(), rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref())#

Returns the minhash values for each row of strings per seed.

Hash values are computed from each string in each row and the minimum hash value is returned for each row for each seed. Each row of the output list column are seed results for the corresponding input row. 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.

Deprecated:

Deprecated in 24.12

Throws:

  • std::invalid_argument – if seeds is empty

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

Parameters:

  • input – Lists column of strings to compute minhash

  • seeds – Seed values used for the hash algorithm

  • 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> word_minhash64(cudf::lists_column_view const &input, cudf::device_span<uint64_t const> seeds, rmm::cuda_stream_view stream = cudf::get_default_stream(), rmm::device_async_resource_ref mr = cudf::get_current_device_resource_ref())#

Returns the minhash values for each row of strings per seed.

Hash values are computed from each string in each row and the minimum hash value is returned for each row for each seed. Each row of the output list column are seed results for the corresponding input row. 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 though only the first 64-bits of the hash are used in computing the output.

Any null row entries result in corresponding null output rows.

Deprecated:

Deprecated in 24.12

Throws:

  • std::invalid_argument – if seeds is empty

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

Parameters:

  • input – Lists column of strings to compute minhash

  • seeds – Seed values used for the hash algorithm

  • 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