deleted warmup, use fva instead

src/analysis/sampling/warmup.jl

-"""
-    _get_warmup_points(cbm; random_objective=false, numstop=Inf)
-
-Generate warmup points for all reactions in the model that are not fixed.
-Assumes that the input JuMP model in `cbm` is already constrained.
-
-The warmup points are sampled randomly from all possibilities until `numstop`
-is reached; by default all points are generated.
-
-By default, the warmup points are generated as in FVA by minimizing and
-maximizing all reactions; `random_objective` switches this to completely random
-objectives.
-"""
-function _get_warmup_points(cbm; random_objective = false, numstop = Inf)
-    v = cbm[:x]
-    ubs = cbm[:ubs]
-    lbs = cbm[:lbs]
-    # determine which rxns should be max/min-ized (non fixed fluxes)
-    fixed_rxns = Int[]
-    for i in eachindex(v)
-        ub_val = normalized_rhs(ubs[i])
-        lb_val = normalized_rhs(lbs[i])
-        if ub_val >= 0 && ub_val == -lb_val
-            push!(fixed_rxns, i)
-        elseif ub_val < 0 && -ub_val == lb_val
-            push!(fixed_rxns, i)
-        end
-    end
-
-    # determine number of warmup points (if numstops is less than the number of non-fixed reactions.)
-    var_rxn_inds = shuffle!(filter(x -> !(x in fixed_rxns), 1:length(v))) # shuffle the optimization points
-    NN = numstop > length(var_rxn_inds) ? length(var_rxn_inds) : numstop
-    wpoints = zeros(length(v), 2 * NN)
-
-    # generate warmup points.
-    for (i, ii) in zip(1:length(var_rxn_inds), 1:2:(2*length(var_rxn_inds)))
-        i > NN && break
-
-        if random_objective
-            @objective(cbm, Max, sum(rand() * v[iii] for iii in var_rxn_inds))
-        else
-            @objective(cbm, Max, v[var_rxn_inds[i]])
-        end
-
-        optimize!(cbm)
-        for j = 1:size(wpoints, 1)
-            wpoints[j, ii] = value(v[j])
-        end
-
-        if random_objective
-            @objective(cbm, Min, sum(rand() * v[iii] for iii in var_rxn_inds))
-        else
-            @objective(cbm, Min, v[var_rxn_inds[i]])
-        end
-
-        optimize!(cbm)
-        for j = 1:size(wpoints, 1)
-            wpoints[j, ii+1] = value(v[j])
-        end
-    end
-
-    return wpoints
-end