refactor: remove dead code in structural transformations

Author: AayushSabharwal

src/structural_transformation/utils.jl

@@ -352,50 +352,6 @@ function but_ordered_incidence(ts::TearingState, varmask = highest_order_variabl
     mm[[var_eq_matching[v] for v in vordering if var_eq_matching[v] isa Int], vordering], bb
 end
 
-# debugging use
-function reordered_matrix(sys, torn_matching)
-    s = TearingState(sys)
-    complete!(s.structure)
-    @unpack graph = s.structure
-    eqs = equations(sys)
-    nvars = ndsts(graph)
-    max_matching = complete(maximal_matching(graph))
-    torn_matching = complete(torn_matching)
-    sccs = find_var_sccs(graph, max_matching)
-    I, J = Int[], Int[]
-    ii = 0
-    M = Int[]
-    solved = BitSet(findall(torn_matching .!== unassigned))
-    for vars in sccs
-        append!(M, filter(in(solved), vars))
-        append!(M, filter(!in(solved), vars))
-    end
-    M = invperm(vcat(M, setdiff(1:nvars, M)))
-    for vars in sccs
-        e_solved = [torn_matching[v] for v in vars if torn_matching[v] !== unassigned]
-        for es in e_solved
-            isdiffeq(eqs[es]) && continue
-            ii += 1
-            js = [M[x] for x in 𝑠neighbors(graph, es) if isalgvar(s.structure, x)]
-            append!(I, fill(ii, length(js)))
-            append!(J, js)
-        end
-
-        e_residual = setdiff(
-            [max_matching[v]
-             for v in vars if max_matching[v] !== unassigned], e_solved)
-        for er in e_residual
-            isdiffeq(eqs[er]) && continue
-            ii += 1
-            js = [M[x] for x in 𝑠neighbors(graph, er) if isalgvar(s.structure, x)]
-            append!(I, fill(ii, length(js)))
-            append!(J, js)
-        end
-    end
-    # only plot algebraic variables and equations
-    sparse(I, J, true)
-end
-
 """
     uneven_invmap(n::Int, list)
 
@@ -432,23 +388,6 @@ function torn_system_jacobian_sparsity(sys)
     return sparse(I, J, true, neqs, neqs)
 end
 
-###
-### Nonlinear equation(s) solving
-###
-
-@noinline function nlsolve_failure(rc)
-    error("The nonlinear solver failed with the return code $rc.")
-end
-
-function numerical_nlsolve(f, u0, p)
-    prob = NonlinearProblem{false}(f, u0, p)
-    sol = solve(prob, SimpleNewtonRaphson())
-    rc = sol.retcode
-    (rc == ReturnCode.Success) || nlsolve_failure(rc)
-    # TODO: robust initial guess, better debugging info, and residual check
-    sol.u
-end
-
 ###
 ### Misc
 ###