# ComponentArray and generation of JumpSet

**URL:** <https://discourse.julialang.org/t/componentarray-and-generation-of-jumpset/127875>\
**Category:** General Usage\
**Tags:** componentarrays\
**Created:** [April 9, 2025, 6:05am UTC](https://discourse.julialang.org/t/componentarray-and-generation-of-jumpset/127875 "2025-04-09T06:05:20Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![paolo-mgi](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/paolo-mgi/32/209506_2.png) [@paolo-mgi](https://discourse.julialang.org/u/paolo-mgi)\
**Post date:** [April 9, 2025, 6:05am UTC](https://discourse.julialang.org/t/componentarray-and-generation-of-jumpset/127875/1 "2025-04-09T06:05:20Z")

</div>

Hello,

I wish to integrate a system of jump differential equations with JumpProblem. Variables in the system behave differently and I discrimiate between them using ComponentArray. The problem requires the definition of multiple jumps. I encounter the following problem. If I define the **affect!** functions manually one-by-one the code works as expected. If instead I create them with a function I get the error **type NamedTuple has no field u**. I spent some time inquiring the error but to no avail. I would be very interested to know what I am doing wrong.  
Many thanks for your attention.

Below the two codes. The first works as expected

```julia
function psi!(du, u, p, t)
   du.st_vec .= 0.0
   du.mpr = 6.0.*c(t)*u.mpr/4.0
   du.jpr = 0.0 
end
sse_prob = ODEProblem(psi!, u0, (0.0, tf),p)
function rate!(u,p,t)
   return c(t)/4.0 
end 
# "Manual" definition of the affect functions
function affect1!(integrator)
      v = copyto!(integrator.p.tmp_psi, integrator.u.u.st_vec) # copy this to avoid aliasing later
      mart = integrator.u.u.mpr 
      jump = integrator.u.u.jpr 
      jump_prob = real(dot(v,v))
      if jump_prob > 0.0
         normv = sqrt(jump_prob)
      else
         normv=1.0
      end
      mul!(integrator.u.u.st_vec, integrator.p.jump_ops[1], v, 1/normv,false)
      integrator.u.u.mpr = -2.0*mart 
      integrator.u.u.jpr = -2.0*jump 
      nothing
    end

function affect2!(integrator)
      v = copyto!(integrator.p.tmp_psi, integrator.u.u.st_vec) # copy this to avoid aliasing later
      mart = integrator.u.u.mpr 
      jump = integrator.u.u.jpr 
      jump_prob = real(dot(v,v))
      if jump_prob > 0.0
         normv = sqrt(jump_prob)
      else
         normv=1.0
      end
      mul!(integrator.u.u.st_vec, integrator.p.jump_ops[2], v, 1/normv,false)
      integrator.u.u.mpr = -2.0*mart 
      integrator.u.u.jpr = -2.0*jump 
      nothing
    end

function affect3!(integrator)
      v = copyto!(integrator.p.tmp_psi, integrator.u.u.st_vec) # copy this to avoid aliasing later
      mart = integrator.u.u.mpr 
      jump = integrator.u.u.jpr 
      jump_prob = real(dot(v,v))
      if jump_prob > 0.0
         normv = sqrt(jump_prob)
      else
         normv=1.0
      end
      mul!(integrator.u.u.st_vec, integrator.p.jump_ops[3], v, 1/normv,false)
      integrator.u.u.mpr = -2.0*mart 
      integrator.u.u.jpr = -2.0*jump 
      nothing
    end
# Construction of the JumpSet
jump1=VariableRateJump(rate!, affect1!)
jump2=VariableRateJump(rate!, affect2!)
jump3=VariableRateJump(rate!, affect3!)
jump_prob = JumpProblem(sse_prob, DirectFW(), jump1,jump2,jump3 );
ensemble_sse = EnsembleProblem(jump_prob)
jump_sol_sse = DifferentialEquations.solve(ensemble_sse, Tsit5(), EnsembleSerial(), trajectories=num_traj; save_everystep=true, dense=false,abstol=1e-8,reltol=1e-8,maxiters=Int(1e6));

```

As said the above code gives the expected result.  
If I now replace the second part of the above with

```julia
# Function to construct the distinct Jumps
function create_jump_affect(affected_id::Int) 
    function jump_affect_by_id!(integrator)
      v = copyto!(integrator.p.tmp_psi, integrator.u.u.st_vec) # copy this to avoid aliasing later
      mart = integrator.u.u.mpr 
      jump = integrator.u.u.jpr 
      jump_prob = real(dot(v,v))
      if jump_prob > 0.0
         normv = sqrt(jump_prob)
      else
         normv=1.0
      end
      mul!(integrator.u.u.st_vec, integrator.p.jump_ops[affected_id], v, 1/normv,false)
      integrator.u.u.mpr = -2.0*mart 
      integrator.u.u.jpr = -2.0*jump 
      nothing
    end
    return jump_affect_by_id!
end
# Generate individual jumps by putting them in an array
jumps = VariableRateJump[]   
for i in 1:3
    push!(jumps,VariableRateJump(rate!, create_jump_affect(i)))
end
# Create a JumpSet with the provided constant rate jumps and empty/nil for other jump types
function create_jump_set(variable_jumps::Vector{VariableRateJump})
    return JumpSet((), tuple(variable_jumps...), nothing, nothing)
end
# JumpSet
jump_prob = JumpProblem(sse_prob, DirectFW(), jumpset )
ensemble_sse = EnsembleProblem(jump_prob)
jump_sol_sse = DifferentialEquations.solve(ensemble_sse, Tsit5(), EnsembleSerial(), trajectories=num_traj; save_everystep=true, dense=false,abstol=1e-8,reltol=1e-8,maxiters=Int(1e6));

```

I get the error

```julia
type NamedTuple has no field u

```

---

<div class="post-metadata">

**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [April 21, 2025, 8:40am UTC](https://discourse.julialang.org/t/componentarray-and-generation-of-jumpset/127875/2 "2025-04-21T08:40:46Z")

</div>

This is due to the array wrappers in the current VariableRateJump implementation. It should be fixed rather soon with [feat: Introducing vr\_aggregator with VRDirectCB and VRFRMODE by sivasathyaseeelan · Pull Request #477 · SciML/JumpProcesses.jl · GitHub](https://github.com/SciML/JumpProcesses.jl/pull/477)

---

<div class="post-metadata">

**Author:** ![paolo-mgi](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/paolo-mgi/32/209506_2.png) [@paolo-mgi](https://discourse.julialang.org/u/paolo-mgi)\
**Post date:** [April 21, 2025, 10:53am UTC](https://discourse.julialang.org/t/componentarray-and-generation-of-jumpset/127875/3 "2025-04-21T10:53:10Z")

</div>

Many thanks!