Re: [julia-users] Find the indice of the element with the nearest value of a float in an array

[Tim Holy]

Just FYI:

julia> x = 1:0.1:1000000
1.0:0.1:1.0e6

julia> y = collect(x);  # this is the same as y = [x;]

julia> sizeof(x)
32

julia> sizeof(y)
79999928

--Tim

On Sunday, April 10, 2016 07:26:06 AM Fred wrote:
> Maybe my array is too small to see a difference, but if I increase the size
> I will lack of RAM ;)
> 
> julia> x = 1:0.1:1000000
> 1.0:0.1:1.0e6
> 
> julia> @time searchsorted(x, 8.22)
>   0.045590 seconds (33.21 k allocations: 1.535 MB)
> 74:73
> 
> julia> @time searchsorted(x, 8.22)
>   0.000005 seconds (8 allocations: 288 bytes)
> 74:73
> 
> julia> @time searchsorted(x, 8.22)
>   0.000005 seconds (8 allocations: 288 bytes)
> 74:73
> 
> julia> @time closest_index(x,8.22)
>   0.103219 seconds (4.37 k allocations: 222.884 KB)
> 73
> 
> julia> @time closest_index(x,8.22)
>   0.095684 seconds (4 allocations: 160 bytes)
> 73
> 
> julia> @time dicotomy(x, 8.22)
>   0.009142 seconds (3.45 k allocations: 173.973 KB)
> (73,74)
> 
> julia> @time dicotomy(x, 8.22)
>   0.000005 seconds (5 allocations: 192 bytes)
> (73,74)
> 
> julia> @time dicotomy(x, 8.22)
>   0.000004 seconds (5 allocations: 192 bytes)
> (73,74)
> 
> 
> 
> Even better: get rid of the brackets around 1:0.1:100000, and you'll be
> 
> > that
> > much more impressed.
> > 
> > --Tim