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Many HMM libraries for bioinformatics focus on inference tasks, such as likelihood calculation, parameter-fitting, and alignment. Machine Boss can do these things too, but it also introduces a set of operations for manipulation of the state machines themselves. The aim is to make it as easy to quick and easy to prototype automata-based experiments in bioinformatics as it is to prototype regular expressions. In fact, Machine Boss supports regular expression syntax---along with many other file formats and patterns.

Machine Boss allows you to manipulate state machines by concatenating, composing, intersecting, reverse complementing, Kleene-starring, and other such operations. Brief descriptions of these operations are included below. Any state machine resulting from such operations can be run through the usual inference algorithms too (Forward, Backward, Viterbi, EM, beam search, prefix search, and so on).

For example, a protein-to-DNA alignment algorithm like GeneWise can be thought of as the combination of four state machines accounting for the following effects:

  1. sequencing errors (e.g. substitutions)
  2. splicing of introns
  3. translation of DNA to protein
  4. mutation of the protein (e.g. using the BLOSUM62 substitution matrix with affine gaps)

With Machine Boss, each layer in this hierarchy can be separately designed, parameter-fitted, and (if necessary) refactored. Want to turn a global alignment algorithm into a local one? Just flank the model with some wildcard-emitters. Developed a model for a high-accuracy sequencing technology, and now you want to use it with a noisier sequencer? Just bolt on a different error model. Looking for a Shine-Dalgarno sequence upstream of a signal peptide? No problem, just concatenate the models. And so on.

Machine Boss can read HMMER profiles, write GraphViz dotfiles, and run GeneWise-style models. Its native format is a deliberately restricted (simple and validatable) JSON representation of a weighted finite-state transducer.

Citation

Please cite the following paper if you use Machine Boss:

Silvestre-Ryan, Wang, Sharma, Lin, Shen, Dider, and Holmes. Bioinformatics (2020). Machine Boss: Rapid Prototyping of Bioinformatic Automata.

Installation

Machine Boss can be compiled from C++ source, or installed via npm. For installation instructions see INSTALL.md.

Command-line interface

Machine Boss is most easily accessed through a command-line utility, boss, that makes many machine-building operations available through its command-line options - thereby defining a small expression language for building up automata.

A brief usage guide for this tool follows below.

Examples

Build a regex for an N-glycosylation binding site

PROSITE motif PS00001 has the pattern N-{P}-[ST]-{P}. The following command line saves a machine to PS00001.json that generates that motif (the final --eliminate simply optimizes the state space):

boss --generate-chars N \
 --concat --generate-one ACDEFGHIKLMNQRSTVWY \
 --concat --generate-one ST \
 --concat --generate-one ACDEFGHIKLMNQRSTVWY \
 --eliminate >PS00001.json

You can do this more compactly with the --aa-regex option, which parses regular expression syntax (also available are --dna-regex for DNA, --rna-regex for RNA, or --regex for general text)

boss --aa-regex '^N[^P][ST][^P]$' --transpose >PS00001.json

Note that the --aa-regex option (and the other regex options) construct recognizers rather than generators, by convention. (A recognizer is an input machine; a generator is an output machine.) You can convert a recognizer to a generator (and vice versa) by swapping the input and output labels, using --tranpose.

Search the N-glycosylation regex against a MinION read

This command takes the PS00001.json regex from the previous example, runs it through a reverse-translation machine (--preset translate), adds a self-loop with a dummy parameter (--count-copies n), flanks it with a null model (--generate-uniform-dna), and then uses the Forward-Backward algorithm to find the expected usage of the dummy parameter (--counts) when run against the output of a nanopore basecaller stored in a CSV file (see below for more info on the CSV file format)

boss --counts -v6 \
 --generate-uniform-dna \
 --concat \
  --begin \
   PS00001.json --preset translate --double-strand \
   --concat --generate-uniform-dna \
   --count-copies n \
  --end \
 --recognize-csv t/csv/nanopore_test.csv \
 --params data/Ecoli_codon.json

Note that this takes quite a long time! The log messages reveal that the bulk of the time is being taken by sorting the states. This may be optimized in future.

Encode binary data as non-repeating DNA

This example implements a DNA storage code very similar to that of Goldman et al.

To encode we use beam search (--beam-encode). We could also use prefix search, but beam search is generally much faster:

boss --preset bintern --preset terndna --input-chars 1010101 --beam-encode

Note that the encoder is a composite two-stage machine. First it converts base-2 binary to base-3 ternary, using the preset machine bintern; then it converts ternary to nonrepeating DNA, using the preset terndna. We could have done this in two steps:

boss --preset bintern --input-chars 1010101 --beam-encode
boss --preset terndna --input-chars 12022212 --beam-encode

The first step yields the output sequence 12022212; this is the input to the second step, which yields the output sequence CGATATGC. That is the same output we get when we use the composite two-stage machine (--preset bintern --preset terndna).

To decode we can use beam search too:

boss --preset bintern --preset terndna --output-chars CGATATGC --beam-decode

Base-call the output of a neural network run on an Oxford Nanopore MinION read

The file t/csv/nanopore_test.csv was generated by PoreOver. It describes a gapped profile: the five columns represent the probabilities of the four bases, plus a gap. With Machine Boss you can find the most likely sequence, summing over all alignments, and doing a beam search over sequences:

boss --recognize-csv t/csv/nanopore_test.csv --beam-decode

Manipulation of machines

JSON format for specifying state machines

Formally, a machine is defined to be a weighted finite-state transducer consisting of a tuple (Φ,Σ,Γ,ω) where

  • Φ is an ordered finite set, the state space (including start and end states);
  • Σ is an ordered finite set, the input alphabet;
  • Γ is an ordered finite set, the output alphabet;
  • ω(α,β,σ,γ) is the weight of a transition α → β that inputs σ and outputs γ.

Using the Forward algorithm, one can calculate a sequence weight W(X,Y) for any input sequence X and output sequence Y. In this sense, the transducer may be viewed as an infinite-dimensional matrix, indexed by sequences: X is a row index, and Y a column index.

Machine Boss uses a JSON format for transducers that also allows ω to be constructed using algebraic functions of parameters (addition, multiplication, exponentiation, etc.) It further allows the specification of constraints on the parameters, which are used during model-fitting.

In Machine Boss, the start state is always the first state and the end state is always the last (single-state machines where the state is both start and end are allowed).

Special types of machine

Term Implication for W(X,Y)
Generator for set S Zero unless X is the empty string and Y is a member of S (analogous to a row vector; if S contains only one element whose weight is 1, then it's like a unit vector)
Recognizer for set S Zero unless X is a member of S and Y is the empty string (analogous to a column vector)
Identity for set S Zero unless X=Y and X is a member of S

In general, "constraining the output of machine M to be equal to Y" is equivalent to "composing M with a unit-weight recognizer for Y". Similarly, "constraining the input of M to be equal to X" is equivalent to "composing a unit-weight generator for X with M".

Command-line syntax

The boss command does the following

  • Construct a machine via a series of machine expressions specified as command-line arguments
  • Do any required inference with the machine (dynamic programming, decoding, etc.)

For example, the following command creates an recognizer for any DNA sequence containing the subsequence ACGCGT:

boss --recognize-wild-dna --concat --recognize-chars ACGCGT --concat --recognize-wild-dna

This is equivalent to the regular expression /^[ACGT]*ACGCGT[ACGT]*$/.

Some of the operations specified as command-line arguments can be replaced by "opcodes" comprising one or two characters. For example, concatenation (--concat) can be abbreviated as a period, so that the above could be written as

boss --recognize-wild-dna . --recognize-chars ACGCGT . --recognize-wild-dna

If we use --generate instead of --recognize, replace wild-dna (every nucleotide has unit weight) with uniform-dna (every nucleotide has weight 1/4), specify an output sequence with --output-chars, then instead of a regular expression we have a probabilistically-normalized HMM. We can then specify the --loglike option to calculate the log-likelihood of a given output sequence:

boss --generate-uniform-dna . --generate-chars ACGCGT . --generate-uniform-dna --output-chars AAGCAACGCGTAATA --loglike

Compare this log-likelihood (-12.4766, or 18 bits) to the log-likelihood of the null model, which does not specify that the output must contain the motif ACGCGT

boss --generate-uniform-dna --output-chars AAGCAACGCGTAATA --loglike

This log-likelihood (-20.7944, or 30 bits) differs from the previous one by 12 bits; reflecting the information content of the 6-base motif.

The opcodes are listed in full by the command-line help (boss --help). Some of them may need to be quoted in order to prevent the Unix shell from interpreting them as special characters. For example, --begin and --end can be abbreviated (respectively) as opening and closing parentheses, ( and ), but these must be quoted or they will be intercepted by the shell.

An argument that is not an opcode will be interpreted as the filename of a JSON-format machine file.

If more than one machine is specified without any explicit operation to combine them, then composition (matrix multiplication) is implicit. So, for example, this

boss --preset translate --compose --preset dna2rna

is equivalent to this

boss --preset translate --preset dna2rna

Ways of constructing machines

The first column of this table shows options to the boss command, so e.g. the first example may be run by typing boss --generate-one ACGT

Option Description
--generate-one ACGT A unit-weight generator for any one of the specified characters (here A, C, G or T). Similar to a regex character class
--generate-wild ACGT A unit-weight generator for any string made up of the specified characters (here A, C, G or T, i.e. it will output any DNA sequence). Similar to a regex wildcard
--generate-iid ACGT A generator for any string made up of the specified characters, with each character emission weighted (via parameters) to the respective character frequencies. Note that this is not a true probability distribution over output sequences, as no distribution is placed on the sequence length
--generate-uniform ACGT A generator for any string made up of the specified characters, with each character emission weighted uniformly by (1/alphabet size). Note that this is not a true probability distribution over output sequences, as no distribution is placed on the sequence length
--generate-uniform-dna, --generate-uniform-aa etc. Any of the above --generate-XXX forms may have -dna, -rna or -aa tacked on the end, in which case the alphabet does not need to be specified but is taken to be (respectively) ACGT, ACGU or ACDEFGHIKLMNPQRSTVWY
--generate-chars AGATTC A unit-weight generator for the single string specified (which will be split into single-character symbols)
--generate-fasta FILENAME.fasta A unit-weight generator for a sequence of characters read from a FASTA-format file
--generate-csv FILENAME.csv A generator corresponding to a position-specific probability weight matrix stored in a CSV-format file, where the column titles in the first row correspond to output symbols (and a column with an empty title corresponds to gap characters in the weight matrix)
--generate-json FILENAME.json A generator for a sequence of symbols read from a Machine Boss JSON file
--regex REGEX A recognizer state machine for the corresponding regular expression. By default this will be a local regular expression; use the ^ and $ anchors to make it global.
--dna-regex REGEX, --rna-regex REGEX, --aa-regex REGEX A DNA, RNA, or protein regular expression. Practically, the only difference between this and --regex is that the wildcard character (.) is defined for the appropriate (upper-case) molecular residue alphabet, instead of ASCII text.
--hmmer HMMERFILE.hmm A generator corresponding to a HMMer-format profile HMM; or rather, to the version of this state machine used by hmmsearch for local alignment, which is quite different from the HMM described in the model file (it introduces local entry and exit probabilities calculated using an ad hoc formula). Note this still does not include HMMER's odds-ratio weighting (for which you need e.g. --weight-output 1/$pSwissProt% --params data/SwissProtComposition.json) or free flanking states (--flank-output-wild)
--hmmer-global HMMERFILE.hmm This constructs the global alignment version of the profile HMM, which is what is actually described in the HMMER model file

For each of the --generate-XXX options, the --generate can be replaced with --recognize to construct the corresponding recognizer, or (in most cases) with --echo for the identity.

Preset machines

These example machines may be selected using the --preset keyword, e.g. boss --preset null

Name Description
null Identity for the empty string
compdna Complements DNA (but doesn't reverse it)
comprna Complements RNA (but doesn't reverse it)
translate A machine that inputs amino acids and outputs codons (yes, this should probably be called "reverse translate")
prot2dna A GeneWise-style model, finds a protein in DNA
psw2dna Another GeneWise-style model, allows substitutions & indels in the protein
dnapsw A machine that implements probabilistic Smith-Waterman alignment for DNA
protpsw A machine that implements probabilistic Smith-Waterman alignment for proteins
jukescantor A machine that implements the Jukes-Cantor (1969) substitution model for DNA
tkf91branch A machine that implements the Thorne-Kishino-Felsenstein (1991) indel model for DNA, with Jukes-Cantor as a substitution model
tkf91root A machine that generates sequences from the equilibrium distribution of the Thorne-Kishino-Felsenstein indel model
bintern A machine that converts binary digits (in groups of 3) into ternary digits (in group of 2). To handle situations where the input isn't a multiple of 3 bits in length, the machine also outputs an escape code at the end, with any dangling bits converted to ternary
terndna A machine that converts a ternary sequence into a non-repeating DNA sequence. Composed with the bintern preset, this can be used to implement the DNA storage code of Goldman et al
tolower A machine that converts text to lower case
toupper A machine that converts text to upper case
hamming31 A machine that implements a Hamming (3,1) error correction code
hamming74 A machine that implements a Hamming (7,4) error correction code

Operations transforming a single machine

Operation Command Description Analogy
Transpose boss m.json --transpose Swaps the inputs and outputs Matrix transposition
Silence inputs boss m.json --silence-input Clears all the input labels Summing columns
Silence outputs boss m.json --silence-output Clears all the output labels Summing rows
Copy inputs to outputs boss m.json --copy-input-to-output Sets the output labels equal to the input labels Make diagonal matrix from column vector
Copy outputs to inputs boss m.json --copy-output-to-input Sets the input labels equal to the output labels Make diagonal matrix from row vector
Make optional (?) boss m.json --zero-or-one Zero or one tours through m.json Union with the empty-string identity. Like the ? in regexes
Form Kleene closure (+) boss m.json --kleene-plus One or more tours through m.json Like the + in regexes
Form Kleene closure (*) boss m.json --kleene-star Zero or more tours through m.json Like the * in regexes
Count copies boss m.json --count-copies x Like Kleene closure (*), but introducing a dummy unit-weight parameter (in this case, x) which can be used to find posterior-expected estimates of the number of tours of m.json in the path
Take reciprocal boss m.json --reciprocal Take reciprocal of all transition weights Pointwise reciprocal
Repeat boss m.json --repeat 3 Repeat m.json the specified number of times Fixed quantifiers in regexes
Reverse boss m.json --reverse Reverse the machine
Reverse complement boss m.json --revcomp As you might expect
Symmetrize forward & reverse strands boss m.json --double-strand Takes the union of a machine with its reverse complement
Normalize boss m.json --joint-norm Normalize transition weights, so that sum of outgoing weights from each state is 1 Probabilistic normalization
Sort boss m.json --sort Topologically sort the transition graph
Eliminate redundant states boss m.json --eliminate Try to eliminate unnecessary states and transitions

Operations combining two machines

Operation Command Description Analogy
Concatenate boss l.json --concat r.json Creates a combined machine that concatenates l.json's input with r.json's input, and similarly for their outputs String concatenation
Compose boss a.json --compose b.json or boss a.json b.json Creates a combined machine wherein every symbol output by a.json is processed as an input symbol of b.json. Matrix multiplication
Intersect boss a.json --intersect b.json Creates a combined machine wherein every input symbol processed by a.json is also processed as an input symbol by b.json Pointwise product
Take union boss a.json --union b.json Creates a combined machine consisting of a.json and b.json side-by-side; paths can go through one or the other, but not both Pointwise sum
Make loop boss a.json --loop b.json Creates a combined machine that allows one a, followed by any number of ba's Kleene closure with spacer

Combining operations

The above operations may be combined to form complex expressions specifying automata from the command line. The --begin and --end options may be used (rather like left- and right-parentheses) to delimit sub-expressions.

For example, the following composes the protpsw and translate presets, and flanks this composite machine with uniform-DNA generators, thereby constructing a machine that can be used to search DNA (the output) for local ORFs homologous to a query protein (the input):

boss --generate-uniform-dna \
 --concat --begin --preset protpsw --preset translate --end \
 --concat --generate-uniform-dna

JSON and C++ APIs

Most of the above operators for generating and manipulating machines are accessible directly via the C++ API, and can also be specified as JSON expressions within the model file.

Model generation scripts

For when the presets aren't enough, there are scripts in the js/ subdirectory that can generate some useful models.

Application of machines

By default, the machine resulting from any manipulation operations is printed to standard output as a JSON file (or as a GraphViz dot file, if --graphviz was specified). However, there are several inference operations that can be performed on data instead.

Specifying data

There are several ways to specify input and output sequences.

Option Description
--input-chars AGATTA Specify the input as a sequence of characters directly from the command line
--output-chars AGATTA Specify the output as a sequence of characters directly from the command line
--input-fasta FILENAME.fasta Specify the input via a FASTA-format file
--output-fasta FILENAME.fasta Specify the output via a FASTA-format file
--data SEQPAIRS.json Specify pairs of input & output sequences via a JSON-format file

Dynamic programming algorithms

Option Description
--loglike Forward algorithm
--train Baum-Welch training, using generic optimizers from GSL
--viterbi Viterbi score only
--align Viterbi alignment
--counts Calculates derivatives of the log-weight with respect to the logs of the parameters, a.k.a. the posterior expectations of the number of time each parameter is used
--beam-decode Uses beam search to find the most likely input for a given output. Beam width can be specified using --beam-width
--beam-encode Uses beam search to find the most likely output for a given input
--viterbi-decode Uses Viterbi algorithm to find the input sequence for most likely state path consistent with a given output
--viterbi-encode Uses Viterbi algorithm to find the output sequence for most likely state path consistent with a given input
--codegen DIR Generate C++ or JavaScript code implementing the Forward algorithm

JSON schemas

Machine Boss defines JSON schemas for several data structures. Here are some examples of files that fit these schemas:

Help text



General options:
  -h [ --help ]                 display this help message
  -v [ --verbose ] arg (=2)     verbosity level
  -d [ --debug ] arg            log specified function
  -b [ --monochrome ]           log in black & white

Transducer construction:
  -l [ --load ] arg             load machine from file
  -p [ --preset ] arg           select preset (null, compdna, comprna, dnapsw, 
                                protpsw, translate, prot2dna, psw2dna, 
                                iupacdna, iupacaa, dna2rna, rna2dna, bintern, 
                                terndna, jukescantor, dnapswnbr, tkf91root, 
                                tkf91branch, tolower, toupper, hamming31, 
                                hamming74)
  -g [ --generate-chars ] arg   generator for explicit character sequence '<<'
  --generate-one arg            generator for any one of specified characters
  --generate-wild arg           generator for Kleene closure over specified 
                                characters
  --generate-iid arg            as --generate-wild, but followed by 
                                --weight-output '$p%'
  --generate-uniform arg        as --generate-iid, but weights outputs by 
                                1/(output alphabet size)
  --generate-fasta arg          generator for FASTA-format sequence
  --generate-csv arg            create generator from CSV file
  --generate-json arg           sequence generator for JSON-format sequence
  -a [ --recognize-chars ] arg  recognizer for explicit character sequence '>>'
  --recognize-one arg           recognizer for any one of specified characters
  --recognize-wild arg          recognizer for Kleene closure over specified 
                                characters
  --recognize-iid arg           as --recognize-wild, but followed by 
                                --weight-input '$p%'
  --recognize-uniform arg       as --recognize-iid, but weights outputs by 
                                1/(input alphabet size)
  --recognize-fasta arg         recognizer for FASTA-format sequence
  --recognize-csv arg           create recognizer from CSV file
  --recognize-merge-csv arg     create recognizer from CSV file, merging 
                                consecutively repeated characters as in Graves 
                                (2006) 'Connectionist Temporal Classification'
  --recognize-json arg          sequence recognizer for JSON-format sequence
  --echo-one arg                identity for any one of specified characters
  --echo-wild arg               identity for Kleene closure over specified 
                                characters
  --echo-chars arg              identity for explicit character sequence
  --echo-fasta arg              identity for FASTA-format sequence
  --echo-json arg               identity for JSON-format sequence
  -w [ --weight ] arg           weighted null transition '#'
  -X [ --regex ] arg            create text recognizer from regular expression
  -H [ --hmmer ] arg            create generator from HMMER3 model file in 
                                local alignment mode
  --hmmer-global arg            create generator from HMMER3 model file in 
                                global alignment mode
  -J [ --jphmm ] arg            create jumping profile HMM generator from FASTA
                                multiple alignment

Postfix operators:
  -z [ --zero-or-one ]          union with null '?'
  -k [ --kleene-star ]          Kleene star '*'
  -K [ --kleene-plus ]          Kleene plus '+'
  --count-copies arg            Kleene star with dummy counting parameter
  --repeat arg                  repeat N times
  -e [ --reverse ]              reverse
  -r [ --revcomp ]              reverse-complement '~'
  --flank-input-wild            add flanking delete states: partially match 
                                input
  --flank-output-wild           add flanking insert states: partially match 
                                output
  --flank-either-wild           add flanking insert or delete states: partially
                                match either input or output at each end
  --flank-both-wild             add flanking insert & delete states: partially 
                                match input and/or output
  --flank-input-geom arg        like --flank-input-wild, but flanking input 
                                sequence is uniform IID with 
                                geometrically-distributed length, parameterized
                                using specified expression
  --flank-output-geom arg       like --flank-output-wild, but flanking output 
                                sequence is uniform IID with 
                                geometrically-distributed length, parameterized
                                using specified expression
  --double-strand               union of machine with its reverse complement
  -t [ --transpose ]            transpose: swap input/output
  --downsample-size arg         keep only specified proportion of transitions, 
                                discarding those with lowest posterior 
                                probability
  --downsample-prob arg         keep only transitions above specified posterior
                                probability threshold
  --downsample-path arg         stochastically sample specified number of 
                                paths, discard unsampled transitions
  --downsample-frac arg         sample paths until specified fraction of 
                                transitions covered
  --joint-norm                  normalize jointly (outgoing transition weights 
                                sum to 1)
  --cond-norm                   normalize conditionally (outgoing transition 
                                weights for each input symbol sum to 1)
  --sort                        topologically sort, eliminating silent cycles
  --sort-fast                   topologically sort, breaking silent cycles 
                                (faster than --sort, but destructive)
  --sort-cyclic                 topologically sort if possible, but preserve 
                                silent cycles
  --decode-sort                 topologically sort non-outputting transition 
                                graph
  --encode-sort                 topologically sort non-inputting transition 
                                graph
  --full-sort                   topologically sort entire transition graph, not
                                just silent transitions
  -n [ --eliminate ]            eliminate all silent transitions
  --eliminate-states            eliminate all states whose only outgoing (or 
                                incoming) transition is silent
  --strip-names                 remove all state names. Some algorithms (e.g. 
                                composition of large transducers) are faster if
                                states are unnamed
  --pad                         pad with "dummy" start & end states
  --reciprocal                  element-wise reciprocal: invert all weight 
                                expressions
  --weight-input arg            multiply input weights by specified JSON 
                                expression (% expands to input symbol, # to 
                                input alphabet size)
  --weight-output arg           multiply output weights by specified JSON 
                                expression (% expands to output symbol, # to 
                                output alphabet size)
  --weight-input-geom arg       place geometric distribution with specified 
                                parameter over input length
  --weight-output-geom arg      place geometric distribution with specified 
                                parameter over output length
  --silence-input               silence inputs, converting a machine into a 
                                generator
  --silence-output              silence outputs, converting a machine into a 
                                recognizer
  --copy-output-to-input        copy outputs to inputs, converting a generator 
                                into an echo machine
  --copy-input-to-output        copy inputs to outputs, converting a recognizer
                                into an echo machine

Infix operators:
  -m [ --compose ]              compose, summing out silent cycles '=>'
  --compose-fast                compose, breaking silent cycles (faster, 
                                destructive)
  --compose-cyclic              compose, leaving silent cycles
  -c [ --concatenate ]          concatenate '.'
  -i [ --intersect ]            intersect, summing out silent cycles '&&'
  --intersect-fast              intersect, breaking silent cycles (faster, 
                                destructive)
  --intersect-cyclic            intersect, leaving silent cycles
  -u [ --union ]                union '||'
  -o [ --loop ]                 loop: x '?+' y = x(y.x)*
  -f [ --flank ]                flank: y . x . y

Miscellaneous:
  -B [ --begin ]                left bracket '('
  -E [ --end ]                  right bracket ')'

Transducer application:
  -S [ --save ] arg             save machine to file
  -G [ --graphviz ]             write machine in Graphviz DOT format
  --stats                       show model statistics (#states, #transitions, 
                                #params)
  --evaluate                    evaluate all transition weights in final 
                                machine
  --define-exprs                define and re-use repeated (sub)expressions, 
                                for compactness
  --show-params                 show unbound parameters in final machine
  -U [ --use-defaults ]         use defaults (uniform distributions, unit 
                                rates) for unbound parameters; this option is 
                                implicit when training
  --name-states                 use state id, rather than number, to identify 
                                transition destinations
  -P [ --params ] arg           load parameters (JSON)
  -F [ --functions ] arg        load functions & constants (JSON)
  -N [ --constraints ] arg      load normalization constraints (JSON)
  -D [ --data ] arg             load sequence-pairs (JSON)
  -I [ --input-fasta ] arg      load input sequence(s) from FASTA file
  --input-json arg              load input sequence from JSON file
  --input-chars arg             specify input character sequence explicitly
  -O [ --output-fasta ] arg     load output sequence(s) from FASTA file
  --output-json arg             load output sequence from JSON file
  --output-chars arg            specify output character sequence explicitly
  -T [ --train ]                Baum-Welch parameter fit
  -R [ --wiggle-room ] arg      wiggle room (allowed departure from training 
                                alignment)
  -A [ --align ]                Viterbi sequence alignment
  -V [ --viterbi ]              Viterbi log-likelihood calculation
  -L [ --loglike ]              Forward log-likelihood calculation
  -C [ --counts ]               Forward-Backward counts (derivatives of 
                                log-likelihood with respect to logs of 
                                parameters)
  -Z [ --beam-decode ]          find most likely input by beam search
  --beam-width arg              number of sequences to track during beam search
                                (default 100)
  --prefix-decode               find most likely input by CTC prefix search
  --prefix-backtrack arg        specify max backtracking length for CTC prefix 
                                search
  --viterbi-decode              find most likely input by Viterbi traceback
  --cool-decode                 find most likely input by simulated annealing
  --mcmc-decode                 find most likely input by MCMC search
  --decode-steps arg            simulated annealing steps per initial symbol
  -Y [ --beam-encode ]          find most likely output by beam search
  --prefix-encode               find most likely output by CTC prefix search
  --viterbi-encode              find most likely output by Viterbi traceback
  --random-encode               sample random output by stochastic prefix 
                                search
  --seed arg                    random number seed

Parser-generator:
  --codegen arg                 generate parser code, save to specified 
                                directory
  --cpp64                       generate C++ dynamic programming code (64-bit)
  --cpp32                       generate C++ dynamic programming code (32-bit)
  --js                          generate JavaScript dynamic programming code
  --showcells                   include debugging output in generated code
  --compileviterbi              compile Viterbi instead of Forward
  --inseq arg                   input sequence type (String, Intvec, Profile)
  --outseq arg                  output sequence type (String, Intvec, Profile)