Je to možné dosiahnuť hodnotu@NLexpression?

Ako je to možné dosiahnuť hodnotu @NLexpression, keď premenné sú stanovené? V nasledujúci kód premenné majú pevne stanovené, ale hodnota K1 nebol dosiahnutý.

using JuMP, Distributions,Juniper
#-----Model parameters--------------------------------------------------------
sig, C1, c0 = 2, 300, 10;
E, landa, T0, T1, T2, gam1, gam2, a1, a2, a3, ap = 0.05, 0.01, 0, 2, 2, 1, 1, 0.5, 0.1, 50, 25;
xhat=[2.807064523673271;23.0;1.3349699464500042];
f(x) = cdf(Normal(0, 1), x);
#---------------------------------------------------------------------------
ALT= Model(optimizer_with_attributes(Juniper.Optimizer, "nl_solver"=>optimizer_with_attributes(Ipopt.Optimizer, "print_level" => 0),

       "mip_solver"=>optimizer_with_attributes(Gurobi.Optimizer, "logLevel" => 0),"registered_functions" =>[Juniper.register( :f, 1, f; autodiff = true)])

       );

# variables-----------------------------------------------------------------
JuMP.register(ALT, :f, 1, f; autodiff = true);
@variable(ALT, hp == xhat[3]);
@variable(ALT, Lp ==xhat[1]);
@variable(ALT, np==xhat[2], Int);
#---------------------------------------------------------------------------
C1=rand(100:100:300);
sig=rand(0.5:0.5:2);
#---------------------------------------------------------------------------
k1=@NLexpression(ALT,hp/(1-f(Lp-sig*sqrt(np))+f(-Lp - sig*sqrt(np))));
JuMP.value(k1);

chyba je tento:

julia> JuMP.value(k1)
ERROR: type Nothing has no field status
Stacktrace:
 [1] getproperty(::Nothing, ::Symbol) at .\Base.jl:33
 [2] get at C:\Users\admin\.julia\packages\Juniper\dNHnx\src\MOI_wrapper\results.jl:4 [inlined]
 [3] get(::MathOptInterface.Bridges.LazyBridgeOptimizer{Juniper.Optimizer}, ::MathOptInterface.TerminationStatus) at C:\Users\admin\.julia\packages\MathOptInterface\bygN7\src\Bridges\bridge_optimizer.jl:587
 [4] get(::MathOptInterface.Utilities.CachingOptimizer{MathOptInterface.AbstractOptimizer,MathOptInterface.Utilities.UniversalFallback{MathOptInterface.Utilities.Model{Float64}}}, ::MathOptInterface.TerminationStatus) at C:\Users\admin\.julia\packages\MathOptInterface\bygN7\src\Utilities\cachingoptimizer.jl:553
 [5] _moi_get_result(::MathOptInterface.Utilities.CachingOptimizer{MathOptInterface.AbstractOptimizer,MathOptInterface.Utilities.UniversalFallback{MathOptInterface.Utilities.Model{Float64}}}, ::MathOptInterface.VariablePrimal, ::Vararg{Any,N} where N) at C:\Users\admin\.julia\packages\JuMP\YXK4e\src\JuMP.jl:844
 [6] get(::Model, ::MathOptInterface.VariablePrimal, ::VariableRef) at C:\Users\admin\.julia\packages\JuMP\YXK4e\src\JuMP.jl:877
 [7] value(::VariableRef; result::Int64) at C:\Users\admin\.julia\packages\JuMP\YXK4e\src\variables.jl:767
 [8] #103 at C:\Users\admin\.julia\packages\JuMP\YXK4e\src\nlp.jl:1159 [inlined]
 [9] value(::NonlinearExpression, ::JuMP.var"#103#104"{Int64}) at C:\Users\admin\.julia\packages\JuMP\YXK4e\src\nlp.jl:1102
 [10] #value#102 at C:\Users\admin\.julia\packages\JuMP\YXK4e\src\nlp.jl:1159 [inlined]
 [11] value(::NonlinearExpression) at C:\Users\admin\.julia\packages\JuMP\YXK4e\src\nlp.jl:1159
 [12] top-level scope at none:1

mohli by ste, prosím, pomôžte mi, ako chyba je vyriešený? Vďaka.