Struct ApHint 

pub struct ApHint {
    pub call1: Option<String>,
    pub call2: Option<String>,
    pub grid: Option<String>,
    pub report: Option<String>,
}

A Priori information for assisted decoding.

Known callsigns are converted to 28-bit packed tokens and injected as high-confidence LLR values into the BP decoder, effectively reducing the number of unknown bits. This lowers the decode threshold by several dB.

Example

use mfsk_core::ft8::decode::ApHint;
// "I'm calling 3Y0Z, expecting a reply to my CQ"
let ap = ApHint::new().with_call1("CQ").with_call2("3Y0Z");

Fields

call1: Option<String>

Known first callsign (e.g. “CQ”, “JA1ABC”). Locks message bits 0–28 (28-bit call + 1-bit flag).

call2: Option<String>

Known second callsign (e.g. “3Y0Z”). Locks message bits 29–57 (28-bit call + 1-bit flag).

grid: Option<String>

Known grid locator (e.g. “JD34”). Locks message bits 58 (ir=0) + 59–73 (15-bit grid).

report: Option<String>

Known report/response token (e.g. “RRR”, “RR73”, “73”). Locks bits 58–73 (ir flag + 15-bit report field) for full 77-bit lock.

Implementations

impl ApHint

pub fn new() -> Self

Construct an empty ApHint — no fields pre-filled.

pub fn with_call1(self, call: &str) -> Self

Pre-fill the first callsign (CALL1 in a standard FT8 message).

pub fn with_call2(self, call: &str) -> Self

Pre-fill the second callsign (CALL2).

pub fn with_grid(self, grid: &str) -> Self

Pre-fill the 4-character Maidenhead grid.

pub fn with_report(self, rpt: &str) -> Self

Pre-fill the signal report (e.g. "-12", "R+05", "73").

pub fn has_info(&self) -> bool

Returns true if any a-priori information is available.

pub fn build_ap(&self, apmag: f32) -> ([bool; 174], [f32; 174])

Build AP mask and LLR overrides for the 174-bit LDPC codeword.

apmag — magnitude to assign to known bits (typically max(|llr|) * 1.01).

Returns (ap_mask, ap_llr) where:

• ap_mask[i] = true means bit i is a-priori known (frozen in BP)
• ap_llr[i] is the LLR override for known bits (±apmag)

Trait Implementations

impl Clone for ApHint

fn clone(&self) -> ApHint

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ApHint

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ApHint

fn default() -> ApHint

Returns the “default value” for a type.