Simple rcpptimer example

Time the computation of Fibonacci numbers

Usage

fibonacci(n)

Arguments

n

vector giving integers for which to compute the Fibonacci sum

Value

vector of integers giving the Fibonacci sum for each element in n

Details

The function being timed is the following:

int fib(int n) { return ((n <= 1) ? n : fib(n - 1) + fib(n - 2)); }

Runtime for computations less than n = 15 is nearly unmeasurable.

Examples

# \donttest{
fibonacci(n = rep(20:25, 10))
#>  [1]  6765 10946 17711 28657 46368 75025  6765 10946 17711 28657 46368 75025
#> [13]  6765 10946 17711 28657 46368 75025  6765 10946 17711 28657 46368 75025
#> [25]  6765 10946 17711 28657 46368 75025  6765 10946 17711 28657 46368 75025
#> [37]  6765 10946 17711 28657 46368 75025  6765 10946 17711 28657 46368 75025
#> [49]  6765 10946 17711 28657 46368 75025  6765 10946 17711 28657 46368 75025
# this function creates a global environment variable "times"
times
#>          Microseconds    SD      Min      Max Count
#> fib_20         14.160 0.880   13.837   16.661    10
#> fib_21         18.975 0.467   18.775   20.298    10
#> fib_22         36.244 0.828   35.857   38.482    10
#> fib_23         49.628 0.282   49.473   50.405    10
#> fib_24         90.124 0.229   89.889   90.711    10
#> fib_25        131.160 4.948  128.001  141.817    10
#> fib_body     3410.840 0.000 3410.840 3410.840     1
# }