{
    "name": "f1x4",
    "synonyms": [ "F1x4" ],
    "result_type": "List[Pair[String,Double]]",
    "constraints": "Triplets[a,b]",
    "call": "SModel.Codons.f1x4'_frequencies[a,pi]",
    "args": [
        {
            "arg_name": "pi",
            "arg_type": "List[Pair[String,Double]]",
            "default_value": "~dirichlet_on[letters[getNucleotides[@a]],1.0]",
	    "description": "Nucleotide frequencies"
        },
        {
            "arg_name": "a",
            "arg_type": "a",
	    "default_value": "getAlphabet",
	    "description": "The (codon) alphabet"
        }
    ],
    "title": "F1x4 codon frequencies",
    "description": "The F1x4 model describes codon frequencies pi' in terms of nucleotide frequencies pi:\n   pi'[ijk] = pi[i]*pi[l]*pi[k].",
    "examples": ["gy94[pi=f1x4]","f1x4[a=codons[dna]]"],
    "see": ["f3x4","gy94"],
    "extract": "all"
}
