# How can you call a function inside a taylor model function for reachability analysis?
**URL:** https://discourse.julialang.org/t/how-can-you-call-a-function-inside-a-taylor-model-function-for-reachability-analysis/119945
**Category:** General Usage
**Tags:** functions, reachabilityanalysis
**Created:** [September 27, 2024, 10:20am UTC](https://discourse.julialang.org/t/how-can-you-call-a-function-inside-a-taylor-model-function-for-reachability-analysis/119945 "2024-09-27T10:20:22Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Muhammad\_Arsal](https://discourse.julialang.org/u/Muhammad_Arsal)
#### Post date: [September 27, 2024, 10:20am UTC](https://discourse.julialang.org/t/how-can-you-call-a-function-inside-a-taylor-model-function-for-reachability-analysis/119945/1 "2024-09-27T10:20:22Z")
I am using Jupyter Notebook. And I have a grid interploation function. Which gives me the value of a variable based upon the data of other two. But the problem is when I try to run reachability analysis, it starts throwing an error.
MethodError: MethodError: no method matching isless(::Float64, ::TaylorModel1{TaylorN{Float64}, Float64})
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### Author:  [@Muhammad\_Arsal](https://discourse.julialang.org/u/Muhammad_Arsal)
#### Post date: [September 28, 2024, 10:51pm UTC](https://discourse.julialang.org/t/how-can-you-call-a-function-inside-a-taylor-model-function-for-reachability-analysis/119945/3 "2024-09-28T22:51:39Z")
But when I tried to put the constant terms into the function It did not run and gave an error that the function is not defined.
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### Author:  [@Muhammad\_Arsal](https://discourse.julialang.org/u/Muhammad_Arsal)
#### Post date: [September 29, 2024, 9:46am UTC](https://discourse.julialang.org/t/how-can-you-call-a-function-inside-a-taylor-model-function-for-reachability-analysis/119945/4 "2024-09-29T09:46:12Z")
``
using Interpolations
function interpol(x,y)
local TSR = [3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10] # Add your TSR values here
local B = -30:1:30 # This creates a range, convert it to an array if needed
#Define the Cp values (this is the lookup table)
#The rows correspond to TSR values and the columns to B values
local Cp = […] #15x61 matrix. You may take any rand values
#convert Cp to a matrix (make sure it has correct dimensions)
Cp = reshape(Cp, length(TSR), length(B))
#Create an interpolation object
itp = interpolate((x, y), Cp, Gridded(Linear()))
return itp
end
using ReachabilityAnalysis
@taylorize function mymodel!(du, u, p, t)
local j,R,wr,V=3410432,35,2.582,12
b,w,bd = u
du[1] = bd - b
du[2] = (0.5\* 3.14\* R^3\* V^2\* 1.225\* interpol(w_R/V,b)-615139)/j
du[3] = 21.43_(0.5\* 3.14\* R^3\* V^2\* 1.225\* interpol(w_R/V,b)-615139)/j+5.87_(w-wr)
return du
end
X0 = Hyperrectangle(; low=[2,2.58,2], high=[2,2.58,2])
prob = @ivp(x’ = mymodel!(x), dim:3, x(0) ∈ X0);
alg = TMJets(; abstol=1e-20, orderT=10, orderQ=2, maxsteps=500\_000)
sol = solve(prob; T=200.0, alg=alg)
solz = overapproximate(sol, Zonotope);
``