quantize::sgfp4_format¶

Classes¶

	Name
class	quantize::sgfp4_format::CodeMode
class	quantize::sgfp4_format::Layout

Attributes¶

	Name
int	MACROBLOCK_SIZE
int	PAYLOAD_BYTES
int	PAYLOAD_U32
int	ALIGNMENT
int	UINT32_BYTES
int	UINT32_BITS
int	FP4_BITS_PER_CODE
int	FP4_CODES_PER_WORD
int	FP4_NIBBLE_MASK
int	FP4_SIGN_THRESHOLD
int	FP4_CODE_BIAS
int	T158_BITS_PER_CODE
int	T158_CODES_PER_WORD
int	T158_SYMBOL_MASK
int	T158_SYMBOL_POS
int	T158_SYMBOL_NEG
int	T158_RESERVED_WORD_START
int	OFFSET_FLAG_MASK
int	OFFSET_MODE_MASK
int	OFFSET_RESERVED_MASK
int	HALF_SHIFT
int	HALF_MASK
float	FP16_MAX
int	LEAF_FLAG_MASK
int	LEAF_MODE_MASK
int	LEAF_RESERVED_MASK
int	BETA_TRUNC_MASK
int	HEADER_CLEAR_FLAGS_MASK
str	SGFP4_MAGIC
int	SGFP4_VERSION_V2
int	V2_FIXED_HEADER_BYTES
int	V2_HEADER_PAD_BYTES
int	SB_HEADER_LAYOUT_MASK
int	SB_HEADER_RESERVED_SHIFT
int	SPLIT_MAP_BYTES
int	SPLIT_MAP_WORDS
int	SPLIT_MAP_MAX_BITS
int	MIN_LEAF_SIZE

Detailed Description¶

SGFP4 wire-format constants — single source of truth.

Every magic number used by the SGFP4 exporter and reference decoder is
named here exactly once, mirroring the SuperGenius coding standard's rule
against unnamed constants (std. §4.5). Names follow the Python/PEP 8
UPPER_CASE convention, which plays the role that k-prefixed compile-time
constants play in the C++ standard.

All values are normative, taken from "SGFP4: Adaptive Dual-Mode
Macroblock Quantization with GPU-Friendly Unpacking and Verifiable
Decode Semantics" (arXiv v2), sections 3.2, 4.2, 4.3, 6.1, 6.2.

Attributes Documentation¶

variable MACROBLOCK_SIZE¶

int MACROBLOCK_SIZE =  64;

variable PAYLOAD_BYTES¶

int PAYLOAD_BYTES =  2048;

variable PAYLOAD_U32¶

int PAYLOAD_U32 =  PAYLOAD_BYTES // 4;

variable ALIGNMENT¶

int ALIGNMENT =  16;

variable UINT32_BYTES¶

int UINT32_BYTES =  4;

variable UINT32_BITS¶

int UINT32_BITS =  32;

variable FP4_BITS_PER_CODE¶

int FP4_BITS_PER_CODE =  4;

variable FP4_CODES_PER_WORD¶

int FP4_CODES_PER_WORD =  UINT32_BITS // FP4_BITS_PER_CODE;

variable FP4_NIBBLE_MASK¶

int FP4_NIBBLE_MASK =  0xF;

variable FP4_SIGN_THRESHOLD¶

int FP4_SIGN_THRESHOLD =  8;

variable FP4_CODE_BIAS¶

int FP4_CODE_BIAS =  16;

variable T158_BITS_PER_CODE¶

int T158_BITS_PER_CODE =  2;

variable T158_CODES_PER_WORD¶

int T158_CODES_PER_WORD =  UINT32_BITS // T158_BITS_PER_CODE;

variable T158_SYMBOL_MASK¶

int T158_SYMBOL_MASK =  0x3;

variable T158_SYMBOL_POS¶

int T158_SYMBOL_POS =  1;

variable T158_SYMBOL_NEG¶

int T158_SYMBOL_NEG =  2;

variable T158_RESERVED_WORD_START¶

int T158_RESERVED_WORD_START =  256;

variable OFFSET_FLAG_MASK¶

int OFFSET_FLAG_MASK =  0xF;

variable OFFSET_MODE_MASK¶

int OFFSET_MODE_MASK =  0x1;

variable OFFSET_RESERVED_MASK¶

int OFFSET_RESERVED_MASK =  0xC;

variable HALF_SHIFT¶

int HALF_SHIFT =  16;

variable HALF_MASK¶

int HALF_MASK =  0xFFFF;

variable FP16_MAX¶

float FP16_MAX =  65504.0;

variable LEAF_FLAG_MASK¶

int LEAF_FLAG_MASK =  0xF;

variable LEAF_MODE_MASK¶

int LEAF_MODE_MASK =  0x1;

variable LEAF_RESERVED_MASK¶

int LEAF_RESERVED_MASK =  0xE;

variable BETA_TRUNC_MASK¶

int BETA_TRUNC_MASK =  0xFFF0;

variable HEADER_CLEAR_FLAGS_MASK¶

int HEADER_CLEAR_FLAGS_MASK =  0xFFFFFFF0;

variable SGFP4_MAGIC¶

str SGFP4_MAGIC =  b"SGF4";

variable SGFP4_VERSION_V2¶

int SGFP4_VERSION_V2 =  0x02;

variable V2_FIXED_HEADER_BYTES¶

int V2_FIXED_HEADER_BYTES =  16;

variable V2_HEADER_PAD_BYTES¶

int V2_HEADER_PAD_BYTES =  7;

variable SB_HEADER_LAYOUT_MASK¶

int SB_HEADER_LAYOUT_MASK =  0x7;

variable SB_HEADER_RESERVED_SHIFT¶

int SB_HEADER_RESERVED_SHIFT =  3;

variable SPLIT_MAP_BYTES¶

int SPLIT_MAP_BYTES =  12;

variable SPLIT_MAP_WORDS¶

int SPLIT_MAP_WORDS =  3;

variable SPLIT_MAP_MAX_BITS¶

int SPLIT_MAP_MAX_BITS =  85;

variable MIN_LEAF_SIZE¶

int MIN_LEAF_SIZE =  4;

Updated on 2026-07-25 at 22:56:57 +0000