My data

Trying to fit a gaussian (not `Normal`

, because it has arbitrary amplitude) on a peak in my data produces very bad parameter values. Expected should be close to my initial guesses, but it outputs [14936.170188518823, 1.1517122795420878e6, 886780.0024262934].

If I try to add upper or lower bounds, it just spits them back at me. If I make the bounds too close to each other, it spits my initial guess back at me.

I’m not really too sure how to fix this as my experience in “curve fitting theory” is practically zero.

Another issue that I came across is that if I give it integers as initial guesses, then the fitting breaks and gives me `Inexact Error: Int64(NaN)`

, which doesn’t tell me anything useful.

Code example:

```
function import_data(pattern::String=".csv"; directory::String="./")
filenames = filter(x -> occursin(pattern, x), readdir(directory))
data = CSV.read.(filenames, DataFrame, header=["Index", "Pixel", "Amplitude"], drop=[:Index], skipto=2)
return (filenames, data)
end
_, data = import_data()
gauss(x, A, μ, σ) = A * exp(-0.5(x - μ)^2 / σ^2)
log_gauss(x, A, μ, σ) = A - 0.5(x - μ)^2 / σ^2
dat = data[1][1620:1640, :]
@. model(x, p) = gauss(x, p[1], p[2], p[3])
p0 = [1.0, 1650.0, 2.0]
fit = curve_fit(model, dat.Pixel, dat.Amplitude, p0)
coef(fit)
```

Error stack trace for the integer initial guessing problem:

Stacktrace:

[1] Int64(x::Float64)

@ Base .\float.jl:912

[2] alloc_DF(x::Vector{Int64}, F::Vector{Float64})

@ NLSolversBase C:\Users\Jacques.julia\packages\NLSolversBase\kavn7\src\objective_types\abstract.jl:19

[3] lmfit(f::LsqFit.var"#18#20"{…}, p0::Vector{…}, wt::Vector{…}; autodiff::Symbol, kwargs::@Kwargs{})

@ LsqFit C:\Users\Jacques.julia\packages\LsqFit\OglWj\src\curve_fit.jl:71

[4] lmfit(f::Function, p0::Vector{Int64}, wt::Vector{Int64})

@ LsqFit C:\Users\Jacques.julia\packages\LsqFit\OglWj\src\curve_fit.jl:54

[5] curve_fit(model::var"#model#278"{…}, xdata::Vector{…}, ydata::Vector{…}, p0::Vector{…}; inplace::Bool, kwargs::@Kwargs{})

@ LsqFit C:\Users\Jacques.julia\packages\LsqFit\OglWj\src\curve_fit.jl:140

[6] curve_fit(model::Function, xdata::Vector{Int64}, ydata::Vector{Int64}, p0::Vector{Int64})

@ LsqFit C:\Users\Jacques.julia\packages\LsqFit\OglWj\src\curve_fit.jl:123