bb::plookup::sparse_tables Namespace Reference

Functions
template<uint64_t base, uint64_t num_rotated_bits>
std::array< bb::fr, 2 >	get_sparse_table_with_rotation_values (const std::array< uint64_t, 2 > key)
	Computes the C2 and C3 column values for a sparse lookup table with optional rotation.
template<uint64_t base, uint64_t bits_per_slice, uint64_t num_rotated_bits>
BasicTable	generate_sparse_table_with_rotation (BasicTableId id, const size_t table_index)
	Generates a BasicTable for converting values to sparse form with optional rotation.
template<size_t base, const uint64_t * base_table>
std::array< bb::fr, 2 >	get_sparse_normalization_values (const std::array< uint64_t, 2 > key)
	Computes the normalized output for a sparse value based on a provided normalization table.
template<size_t base, uint64_t num_bits, const uint64_t * base_table>
BasicTable	generate_sparse_normalization_table (BasicTableId id, const size_t table_index)
	Generates a BasicTable for normalizing sparse form values back to normal form.

Function Documentation

generate_sparse_normalization_table()

template<size_t base, uint64_t num_bits, const uint64_t * base_table>

BasicTable bb::plookup::sparse_tables::generate_sparse_normalization_table ( BasicTableId  id, const size_t  table_index  )

inline

Generates a BasicTable for normalizing sparse form values back to normal form.

This table converts sparse arithmetic results into actual bit values. Each sparse digit encodes a sum of bits; the normalization table extracts the XOR result (and optionally other Boolean function results like Ch or Maj).

Table structure (base^num_bits many entries):

• C1 (input): All possible sparse values with num_bits digits
• C2 (output): Normalized result where each sparse digit is mapped through base_table
• C3: Unused (always 0)

The num_bits parameter controls how many bits are normalized per lookup. Larger num_bits = fewer lookups needed, but larger table.

Template Parameters

base	The sparse form base
num_bits	Number of sparse digits (= original bits) processed per lookup
base_table	The per-digit normalization table (e.g., choose_normalization_table)

Definition at line 144 of file sparse.hpp.

generate_sparse_table_with_rotation()

template<uint64_t base, uint64_t bits_per_slice, uint64_t num_rotated_bits>

BasicTable bb::plookup::sparse_tables::generate_sparse_table_with_rotation ( BasicTableId  id, const size_t  table_index  )

inline

Generates a BasicTable for converting values to sparse form with optional rotation.

Creates a lookup table with three columns:

• C1: Input value in normal form (the lookup key)
• C2: Input converted to sparse base form
• C3: Input rotated by num_rotated_bits, then converted to sparse form (equals C2 if num_rotated_bits == 0)

Step sizes are configured for accumulator building:

• C1 step: 2^11 (SHA-256 decomposes 32-bit words into three limbs of sizes {11, 11, 10} bits)
• C2/C3 step: base^bits_per_slice (for sparse form accumulation)

Also sets get_values_from_key to enable on-the-fly value computation during lookups.

Template Parameters

base	The sparse form base
bits_per_slice	Number of bits in each table entry (determines table size = 2^bits_per_slice)
num_rotated_bits	The number of bits to rotate for C3 values (0 = no rotation)

Definition at line 62 of file sparse.hpp.

get_sparse_normalization_values()

template<size_t base, const uint64_t * base_table>

std::array< bb::fr, 2 > bb::plookup::sparse_tables::get_sparse_normalization_values ( const std::array< uint64_t, 2 >  key )

inline

Computes the normalized output for a sparse value based on a provided normalization table.

Template Parameters

base	The sparse form base
base_table	The normalization lookup table (maps sparse digit → normalized bit(s))

Parameters

key	The lookup key; key[0] is the sparse input value, key[1] is unused

Returns

{normalized_value, 0} where normalized_value has one output bit per input sparse digit

Definition at line 107 of file sparse.hpp.

get_sparse_table_with_rotation_values()

template<uint64_t base, uint64_t num_rotated_bits>

std::array< bb::fr, 2 > bb::plookup::sparse_tables::get_sparse_table_with_rotation_values ( const std::array< uint64_t, 2 >  key )

inline

Computes the C2 and C3 column values for a sparse lookup table with optional rotation.

Template Parameters

base	The sparse form base
num_rotated_bits	The number of bits to rotate the input by for the C3 value (0 = no rotation)

Parameters

key	The lookup key; key[0] is the input value (a limb), key[1] is unused

Returns

{C2, C3} where:

• C2 = sparse(input): the input converted to sparse base form
• C3 = sparse(rotate32(input, num_rotated_bits)): the rotated input in sparse form (equals C2 if num_rotated_bits == 0)

Definition at line 30 of file sparse.hpp.