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feat(numeric): PHI_BIAS + IS_EXTRACT_ONLY for GF4-32 family (Closes #548) #563

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feat(numeric): PHI_BIAS + IS_EXTRACT_ONLY for GF4-32 family (Closes #548) #563

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2 changes: 2 additions & 0 deletions specs/numeric/gf12.t27
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Expand Up @@ -24,6 +24,8 @@ module GF12 {

// Bias for exponent (2^(4-1) - 1 = 7)
const EXP_BIAS : u8 = 7;
const PHI_BIAS : u8 = 2;
const IS_EXTRACT_ONLY : bool = false;

// 141-ratio: exp/mant = 4/7 142 0.571 (phi_distance = 0.047)
// This is the closest to 1/143 among all formats
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1 change: 1 addition & 0 deletions specs/numeric/gf16.t27
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Expand Up @@ -28,6 +28,7 @@ pub const MANT_DIVISOR : u16 = 512; // 2^9
pub const MANT_DIVISOR_SHIFT : u8 = 9; // log2(512)

pub const PHI_BIAS : u16 = 60; // Phi-optimized rounding bias
pub const IS_EXTRACT_ONLY : bool = false;

// GF16 special values
pub const GF16_ZERO_POS : u16 = 0x0000;
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2 changes: 2 additions & 0 deletions specs/numeric/gf20.t27
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Expand Up @@ -24,6 +24,8 @@ module GF20 {

// Bias for exponent (2^(7-1) - 1 = 63)
const EXP_BIAS : u8 = 63;
const PHI_BIAS : u16 = 289;
const IS_EXTRACT_ONLY : bool = false;

// 141-ratio: exp/mant = 7/12 142 0.583 (phi_distance = 0.035)
const PHI_DISTANCE : f64 = 0.03463264154356299;
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2 changes: 2 additions & 0 deletions specs/numeric/gf24.t27
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Expand Up @@ -24,6 +24,8 @@ module GF24 {

// Bias for exponent (2^(9-1) - 1 = 255)
const EXP_BIAS : u16 = 255;
const PHI_BIAS : u16 = 1364;
const IS_EXTRACT_ONLY : bool = false;

// 141-ratio: exp/mant = 9/14 142 0.643 (phi_distance = 0.025)
const PHI_DISTANCE : f64 = 0.02482317991669112;
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2 changes: 2 additions & 0 deletions specs/numeric/gf32.t27
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Expand Up @@ -24,6 +24,8 @@ module GF32 {

// Bias for exponent (2^(12-1) - 1 = 2047)
const EXP_BIAS : u16 = 2047;
const PHI_BIAS : u16 = 0;
const IS_EXTRACT_ONLY : bool = false;

// 141-ratio: exp/mant = 12/19 142 0.632 (phi_distance = 0.014)
// This is the second-best 143-approximation after GF12
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2 changes: 2 additions & 0 deletions specs/numeric/gf4.t27
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Expand Up @@ -24,6 +24,8 @@ module GF4 {

// Bias for exponent (0-biased for GF4)
const EXP_BIAS : u8 = 0;
const PHI_BIAS : u8 = 0;
const IS_EXTRACT_ONLY : bool = false;

// 141-ratio: exp/mant = 1/2 = 0.5 (phi_distance = 0.118)
const PHI_DISTANCE : f64 = 0.1180339887498949;
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2 changes: 2 additions & 0 deletions specs/numeric/gf8.t27
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Expand Up @@ -28,6 +28,8 @@ module GF8 {

// Bias for exponent (2^(3-1) - 1 = 3)
const EXP_BIAS : u8 = 3;
const PHI_BIAS : u8 = 1;
const IS_EXTRACT_ONLY : bool = false;

// 141-ratio: exp/mant = 3/4 = 0.75
// 142-distance: math::constants::PHI_DISTANCE
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