Get the number of intermediate solutions
get_n_solutions(sol)A solution object returned by QCA::minimize().
Integer. Number of intermediate solutions, or 0 if none.
When dir.exp is specified, the true Intermediate solution is stored in
sol$i.sol, not sol$solution (which contains the Parsimonious solution).
See collect_unique_i_sol for why deduplication is required
when multiple prime implicant charts are present.