[R] How to find inverse of glm model?

[Luigi Marongiu]

I have fitted a glm model to some data; how can I find the inverse
function of this model? Since I don't know the y=f(x) implemented by
glm (this works under the hood), I can't define a f⁻¹(y).
Is there an R function that can find the inverse of a glm model?
Thank you.

The working example is:
```
V = c(120.64,    66.14,    34.87,    27.11,    8.87,    -5.8,    4.52,
   -7.16,    -17.39,
            -14.29,    -20.26,    -14.99,    -21.05,    -20.64,
-8.03,    -21.56,    -1.28,    15.01,
            75.26,    191.76,    455.09,    985.96,    1825.59,
2908.08,    3993.18,    5059.94,
            6071.93,    6986.32,    7796.01,    8502.25,    9111.46,
 9638.01,    10077.19,
            10452.02,    10751.81,    11017.49,    11240.37,
11427.47,    11570.07,    11684.96,
            11781.77,    11863.35,    11927.44,    11980.81,
12021.88,    12058.35,    12100.63,
            12133.57,    12148.89,    12137.09)
df = data.frame(Cycles = 1:35, Values = V[1:35])
M = max(df$Values)
df$Norm = df$Values/M
df$Norm[df$Norm<0] = 0
b_model = glm(Norm ~ Cycles, data=df, family=binomial)
plot(Norm ~ Cycles, df, main="Normalized view",
     xlab=expression(bold("Time")),
     ylab=expression(bold("Signal (normalized)")),
     type="p", col="cyan")
lines(b_model$fitted.values ~ df$Cycles, col="blue", lwd=2)
```