# How do I plot?

xfirst=rand(-5:5)

for n=1:100

``````a=rand(-0.1:0.1)

xnew=xfirst+(xfirst*a)

if mainfonk(xnew)>mainfonk(xfirst)

xfirst=xnew

println(mainfonk(xfirst))

end
``````

end

Hi. I am working hill climbing in julia. I am trying to find how can I create graph this code. But I didnt find. I want to create a graph by printing the resulting S values on the y axis and the number of iterations it finds on the x axis.Can you help me?

Hi there! The word used is likely “plot” rather than “graph”. So if you search your tutorials or manuals for “plot” you should find some clues. There’s a JuliaPlots organzsation, which should be a good place to start learning.

Besides the plotting, there are some issues with your code. For example, `rand(-0.1:0.1)` always gives you the same result, and `xnew=xfirst+(xfirst*a)` never makes progress when `xfirst` is zero.

You could rewrite it like this (requires Plots and Distributions package):

``````import Distributions: Uniform

# one iteration
function step(xfirst,mainfct)
a=rand(Uniform(-0.1,0.1))
xnew=xfirst+a
if mainfct(xnew)>mainfct(xfirst)
return xnew
end
return xfirst
end

function runSteps(xfirst,mainfct,n=100)
xarr = [xfirst]
for i=1:n
xfirst = step(xfirst,mainfct)
push!(xarr, xfirst)
end
return xarr
end

mainfct(x) = (x+1.0)^2 # your input function

xfirst = 0.0 # starting value
xarr = runSteps(xfirst, mainfct, 100) # run 100 steps
yarr = mainfct.(xarr) # get function values

using Plots
plot(0:length(yarr)-1, yarr, xlabel="iterations", ylabel="function value at iteration",label="")
``````
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There are a number of actively maintained packages around for plotting. They differ in the kind of interface they provide, the features etc. I believe the most widely used ones right now are probably Gadfly.jl, Makie.jl, PlotlyJS.jl, Plots.jl and VegaLite.jl (in alphabetical order). I might well have missed some 