hfst-reweight

Purpose

Reweight transducer weights simply.

Usage

The help message:

Usage: hfst-reweight [OPTIONS...] [INFILE]
Reweight transducer weights simply

Common options:
  -h, --help             Print help message
  -V, --version          Print version info
  -v, --verbose          Print verbosely while processing
  -q, --quiet            Only print fatal erros and requested output
  -s, --silent           Alias of --quiet
Input/Output options:
  -i, --input=INFILE     Read input transducer from INFILE
  -o, --output=OUTFILE   Write output transducer to OUTFILE
Reweighting options:
  -a, --addition=AVAL        add AVAL to matching weights
  -b, --multiplier=BVAL      multiply matching weights by BVAL
  -F, --function=FNAME       operate matching weights by FNAME
  -l, --lower-bound=LVAL     match weights greater than LVAL
  -u, --upper-bound=UVAL     match weights less than UVAL
  -I, --input-symbol=ISYM    match arcs with input symbol ISYM
  -O, --output-symbol=OSYM   match arcs with output symbol OSYM
  -S, --symbol=SYM           match arcs with input or output symbol SYM or both
  -e, --end-states-only      match end states only, no arcs
  -A, --arcs-only            match arcs only, no end states
  -T, --tsv-file=TFILE       read reweighting rules from TFILE


If OUTFILE or INFILE is missing or -, standard streams will be used.
Format of result depends on format of INFILE
If AVAL, BVAL or FNAME are omitted, they default to neutral elements of addition, multiplication or identity function.
If LVAL or UVAL are omitted, they default to minimum and maximum values of the weight structure.
If ISYM, OSYM or SYM are omitted, they default to a value that matches all arcs.
Only one ISYM, OSYM and SYM can be given.

Float values are parsed with strtod(3) and integers strtoul(3).
The functions allowed for FNAME are <cmath> float functions with parameter count of 1 and a matching return value:
abs, acos, asin, ... sqrt, tan, tanh

The precedence of operands follows the formula BVAL * FNAME(w) + AVAL.
The formula is applied iff:
((LVAL <= w) && (w <= UVAL)),
where w is weight of arc, and
(ISYM == i) && (OSYM == o) && ((SYM == i) || (SYM == o)) ^^
(end state && -e).

TFILE should contain lines with tab-separated pairs of SYM and AVAL or BVAL. AVAL values must be preceded by a + character, BVAL should be given as plain digits. Comment lines starting with # and empty lines are ignored.

Weights are by default modified for all arcs and end states,
unless option --end-states-only or --arcs-only is used.

Report bugs to <hfst-bugs@helsinki.fi> or directly to our bug tracker at:
<https://sourceforge.net/tracker/?atid=1061990&group_id=224521&func=browse>