# Is there a way to run differential equations to a specific point and then change input values, continue running, and graph it together?

**URL:** <https://discourse.julialang.org/t/is-there-a-way-to-run-differential-equations-to-a-specific-point-and-then-change-input-values-continue-running-and-graph-it-together/19232>\
**Category:** New to Julia\
**Tags:** question, diffeq\
**Created:** [January 3, 2019, 10:23am UTC](https://discourse.julialang.org/t/is-there-a-way-to-run-differential-equations-to-a-specific-point-and-then-change-input-values-continue-running-and-graph-it-together/19232 "2019-01-03T10:23:23Z")\
**Posts on this page:** 1\
**Showing post:** 8

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**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:** [January 10, 2019, 7:24pm UTC](https://discourse.julialang.org/t/is-there-a-way-to-run-differential-equations-to-a-specific-point-and-then-change-input-values-continue-running-and-graph-it-together/19232/8 "2019-01-10T19:24:46Z")

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The issue is that you used the argument `callbacks` instead of `callback`. That was my bad (and we really need to error for that). A corrected code is:

```julia
using DifferentialEquations

f = @ode_def_bare ManagedLinear begin
  dBB = r*(1- BB/K)*BB -xI*yIB*BI*((BB^h/(B0^h + BB^h))/eIB)
  dBI = -xI*BI + xI*yIB*BI*(BB^h/(B0^h + BB^h))-xT *yTI*BT*((BI^h/(B0^h + BI^h))/eTI)
  dBT = -xT*BT + xT*yTI*BT*(BI^h/(B0^h + BI^h))-q*BT*E + f1 + f2
end K r yIB yTI eIB eTI B0 h xI xT q E f1 f2

function condition(u,t,integrator)
  t == 200.
end
function affect!(integrator)
  integrator.p[13] = 0.01
end
cb = DiscreteCallback(condition, affect!)

function condition2(u,t,integrator)
  t == 200.
end
function affect2!(integrator)
  integrator.p[14] = 50
end
cb2 = DiscreteCallback(condition2, affect2!)

cbs = CallbackSet(cb,cb2)

u0 = [500.0,200.0,100.0]
tspan = (0.0,1000.0)
p = [450, 1.1, 10, 10, 0.66, 0.85, 80, 1.2, 0.15, 0.06, 0.01, 50, 0, 0] # initial f1 = 0.0 f2 = 0.0
# K r yIB yTI eIB eTI B0 h xI xT q E
prob = ODEProblem(f,u0,tspan,p)
sol=solve(prob,Rosenbrock23(),callback=cbs,tstops=[200.0],reltol=1e-6)

using Plots

plot(sol, title = "Food Chain Managed Linear ", xlabel = "Time" ,ylabel = "Density", lw=0.5)

```

![plot](https://global.discourse-cdn.com/julialang/original/3X/b/6/b6c7402043fb674ccc2954b12fd877d41665cda9.png)

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