added warm start capability to fva and pfba

src/analysis/flux_variability_analysis.jl

@@ -145,6 +145,9 @@ function _FVA_optimize_reaction(model, rid, ret)
     var = all_variables(model)[abs(rid)]
 
     @objective(model, sense, var)
+    if termination_status(model) != MOI.OPTIMIZE_NOT_CALLED && solver_name(model) in ["Gurobi", ]
+        set_start_value.(all_variables(model), value.(all_variables(model))) # warm start
+    end
     optimize!(model)
 
     if is_solved(model)

src/analysis/parsimonious_flux_balance_analysis.jl

@@ -54,6 +54,11 @@ function parsimonious_flux_balance_analysis(
 
     # add the minimization constraint for total flux
     v = opt_model[:x] # fluxes
+
+    if solver_name(opt_model) in ["Gurobi", ]
+        set_start_value.(all_variables(opt_model), value.(all_variables(opt_model))) # warm start
+    end
+    
     @objective(opt_model, Min, sum(dot(v, v)))
 
     for rb in relax_bounds