`x2_sym` — Exchangability matrix on doublets constructed from nucleotide exchange rates

Usage

x2_sym(submodel: ExchangeModel<b>, a: a)
→ ExchangeModel<a>

Type constraints: Doublets<a,b>

submodel:: The singlet exchange model
a:: The Doublets alphabet; Default: The alphabet in the current context

Original default expressions

a

get_state(alphabet)

Exchangability matrix on doublets constructed from an exchangability matrix on nucleotides.

Thus function can be used to build up doublet models incrementally.

HKY85_sym +> x2_sym +> F

GTR_sym +> x2_sym +> F

x2_sym(HKY85_sym)