ExaModels CPU backend acceleration

Specific Domains Optimization (Mathematical)
,
1

I am trying to setup CPU() backend acceleration as described in ExaModels documentation but it is not working. The optimization runs but on single thread (System monitor detects no multiple threads usage) and with the same solution time as if set with nothing. The code was run with julia -t 4 mwe.jl from command line on Linux. Julia 1.11.3 was used.

@sshin23 , @amontoison, @frapac any suggestion on why this does not work?

function luksan_vlcek_obj(x, i)
return 100 * (x[i-1]^2 - x[i])^2 + (x[i-1] - 1)^2
end

function luksan_vlcek_con(x, i)
return 3x[i+1]^3 + 2 * x[i+2] - 5 + sin(x[i+1] - x[i+2])sin(x[i+1] + x[i+2]) + 4x[i+1] -
x[i]exp(x[i] - x[i+1]) - 3
end

function luksan_vlcek_x0(i)
return mod(i, 2) == 1 ? -1.2 : 1.0
end

function luksan_vlcek_model(N, backend = nothing)

c = ExaCore(; backend = backend) # specify the backend
x = variable(c, N; start = (luksan_vlcek_x0(i) for i = 1:N))
constraint(c, luksan_vlcek_con(x, i) for i = 1:N-2)
objective(c, luksan_vlcek_obj(x, i) for i = 2:N)

return ExaModel(c)

end

using ExaModels, NLPModelsIpopt, KernelAbstractions

m = luksan_vlcek_model(2000000, CPU())
ipopt(m)