problem finding inflection

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problem finding inflection

steele500
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Hi,
I have a series of x and y values:

ny<-c(1.608670, 2.126326, 2.562719, 2.927525, 3.229775, 3.477875, 3.679631, 3.842274, 3.972480, 4.076400, 4.159680, 4.227486, 4.284529, 4.335085, 4.383025, 4.431835, 4.484641, 4.544234, 4.613090, 4.693400, 4.787090, 4.895846, 5.021139, 5.164245, 5.326275, 5.508195, 5.710851, 5.934994, 6.181300, 6.450400, 6.742900, 7.059406, 7.400549, 7.767005, 8.159525, 8.578955, 9.026261, 10.502554,10.009110,10.547400, 11.119110, 11.726166, 12.370759, 13.055365, 13.782775, 14.556115, 15.378871, 16.254914, 17.188520, 18.184400, 19.247720, 20.384126, 21.599769, 22.901325, 24.296025, 25.791675, 27.396681, 29.120074, 30.971530, 32.961400, 35.100730, 37.401286, 39.875579, 42.536885)

nx=64:1

I have tried to find the inflection point of the curve. I tried the inflection package and got:

a<-findiplist(nx,ny,0)
Error in if (xf2 < xf1) { : argument is of length zero

I also tried the features package:
 newa<-features(nx, ny)

and this tells me there are 0 critical points, which does not appear correct. I could fit a function to it with nls and then solve for where the function=0, but am I missing something?

Thanks in advance...