[[diverted from R-bugs to R-help by the list maintainer]]
Dear Friend and distinguished R gurus,
first of all really thank you very much for the marvellous tool that is R.
I am using R 2.5.0, windows XP - italian language.
I was perfoming some calculation on fractional exponential and
I found a strange behaviour. I do not know if it is really a bug, but I would
expect
a different answer from R.
I was trying the following :
x <- seq(-3,3, by =0.1)
n <- 2.2
y <- exp(-x^n)
well, the y vector contains (NaN for all negative value of x)
but if you ask for single value calculation like
y <- exp(-(-3)^2.2) or
y <- exp(-(-2.9)^2.2)
the answer is correct.
It seem it does not make the calculation in vector form.
I got the same behaviour (NaN) in a for loop
> for(i in 1:length(x)) y[i]=exp(x[i]^n)
> y
[1] NaN NaN NaN NaN NaN
NaN NaN NaN NaN
[10] NaN NaN NaN NaN NaN
NaN NaN NaN NaN
[19] NaN NaN NaN NaN NaN
NaN NaN NaN NaN
[28] NaN NaN NaN 1.000000 1.006330
1.029416 1.073302 1.142488 1.243137
[37] 1.384082 1.578166 1.844237 2.210260 2.718282
3.432491 4.452553 5.936068 8.137120
[46] 11.473746 16.648415 24.867680 38.251295 60.611092
98.967689 166.572985 289.077778 517.425935
[55] 955.487320 1820.793570 3581.521323 7273.674928 15255.446778
33050.861013 73982.100407
>
Is it strange or did I miss something ?
Many thanks for the attention.
Very best regards
Giuseppe Pedrazzi
Dept Public Health, Physics Division
University of Parma, Italy
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