# Error "POOCollSolution not defined" (DDEBifurcationKit)
**URL:** https://discourse.julialang.org/t/error-poocollsolution-not-defined-ddebifurcationkit/98420
**Category:** New to Julia
**Tags:** question, package
**Created:** [May 6, 2023, 5:17pm UTC](https://discourse.julialang.org/t/error-poocollsolution-not-defined-ddebifurcationkit/98420 "2023-05-06T17:17:28Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@catchia](https://discourse.julialang.org/u/catchia)
#### Post date: [May 6, 2023, 5:17pm UTC](https://discourse.julialang.org/t/error-poocollsolution-not-defined-ddebifurcationkit/98420/1 "2023-05-06T17:17:28Z")
Hello there. I am new to numerical analysis and Julia, and I intend to perform a bifurcation analysis on a two-component DDE system.
(Thanks for the DDEBifurcationKit package @rveltz!)
As a start I attempt to reproduce some of the provided examples here [Github - DDEBifurcationkit Examples](https://github.com/bifurcationkit/DDEBifurcationKit.jl/tree/main/examples).
For instance, with the neuronV2.jl, I encountered this error message while running line 101-111
```julia
br_pocoll = @time continuation(
br, 1, opts_po_cont,
# PeriodicOrbitOCollProblem(100, 4);
probpo;
verbosity = 2, plot = true,
args_po...,
# ampfactor = 1/0.24391300209895822 * 0.1,
ampfactor = 1.42,
δp = 0.001,
normC = norminf,
)
```
It returned an error:
```julia
...
--> Hopf bifurcation point is: SubCritical
┌ Error: Careful here
└ @ DDEBifurcationKit ~/.julia/packages/DDEBifurcationKit/MCTQc/src/periodicorbit/PeriodicOrbits.jl:25
#############################################################
┌─ Start branching from Hopf bif. point to periodic orbits.
├─ Bifurcation type = SubCritical
├─── Hopf param p0 = 0.29890361547229616
├─── new param p = 0.29990361547229616, p - p0 = 0.0010000000000000009
├─── amplitude p.o. = 0.10099414538601163
├─── period T = 23.185428928051927
├─ Method =
┌─ Collocation functional for periodic orbits
├─ type : Vector{Float64}
├─ time slices (Ntst) : 140
├─ degree (m) : 3
├─ dimension (N) : 2
├─ inplace : false
├─ update section : 1
├─ jacobian : autodiffDense
├─ mesh adaptation : false
└─ # unknowns : 842
├─── phase ϕ = 0.548440789574437⋅π
#######################################################
───────────────── PALC ─────────────────
───────────────── INITIAL GUESS ─────────────────ERROR: UndefVarError: POOCollSolution not defined
Stacktrace:
[1] functionalColl!(pb::PeriodicOrbitOCollProblem{ConstantDDEBifProblem{BifFunction{typeof(neuron2VF),
...
```
The same error is observed with other examples that I have tried (neuron.jl, wright.jl).
Could you help me with this error? Thanks in advance for the help!
---
### Author:  [@rveltz](https://discourse.julialang.org/u/rveltz)
#### Post date: [May 6, 2023, 7:42pm UTC](https://discourse.julialang.org/t/error-poocollsolution-not-defined-ddebifurcationkit/98420/2 "2023-05-06T19:42:41Z")
It might be a clash with the recent commits for which have not pushed a tag. Can you try BK@0.2.5 or 0.2.6?
Sorry for this, i can only fix it next week
---
### Author:  [@catchia](https://discourse.julialang.org/u/catchia)
#### Post date: [May 7, 2023, 8:08am UTC](https://discourse.julialang.org/t/error-poocollsolution-not-defined-ddebifurcationkit/98420/3 "2023-05-07T08:08:41Z")
Thanks for the workaround! BK@0.2.4 works for this issue.
---
### Author:  [@rveltz](https://discourse.julialang.org/u/rveltz)
#### Post date: [May 11, 2023, 11:45am UTC](https://discourse.julialang.org/t/error-poocollsolution-not-defined-ddebifurcationkit/98420/4 "2023-05-11T11:45:17Z")
It should be fixed on master now.