Ramanujan primes: Difference between revisions

=={{header|C++}}==

{{trans|Julia}}

#include <cmath>

#include <iomanip>

<< std::chrono::duration<double>(end - start).count() * 1000

<< " milliseconds\n";

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=={{header|F_Sharp|F#}}==

This task uses [http://www.rosettacode.org/wiki/Extensible_prime_generator#The_functions Extensible Prime Generator (F#)]

// Ramanujan primes. Nigel Galloway: September 7th., 2021

let fN g=if isPrime g then 1 else if g%2=1 then 0 else if isPrime(g/2) then -1 else 0

n.[0..99]|>Array.iter(printf "%d "); printfn ""

[1000;10000;100000]|>List.iter(fun g->printf $"The %d{g}th Ramanujan prime is %d{n.[g-1]}\n" )

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<pre>

<br>

This takes about 40 ms to find the 100,000th Ramanujan prime on my machine. The millionth takes about 520 ms.

import (

fmt.Println("\nTook", time.Since(start))

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=={{header|Java}}==

{{trans|C++}}

public class RamanujanPrimes {

private int[] count;

}

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=={{header|Julia}}==

@time let

println("\nThe 10,000th Ramanujan prime is ", Ramanujan_prime(10000))

end

<pre>

2 11 17 29 41 47 59 67 71 97 101 107 127 149 151 167 179 181 227 229

=={{header|Mathematica}}/{{header|Wolfram Language}}==

Multicolumn[1 + Position[l, #][[-1, 1]] & /@ Range[0, 99], {Automatic, 10}, Appearance -> "Horizontal"]

1 + Position[l, 999][[-1, 1]]

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<pre>2 11 17 29 41 47 59 67 71 97

I compiled using command <code>nim c -d:release -d:lto --gc:arc ramanujan_primes.nim</code>, i.e. with runtime checks on, link time optimization and using Arc garbage collector. To find the 100_000th Ramanujan prime, the program runs in about 100 ms on my laptop (i5-8250U CPU @ 1.60GHz, 8 GB Ram, Linux Manjaro).

let t0 = now()

echo "The 100_000th Ramanujan prime is ", ramanujanPrime(pi, 100_000)

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{{trans|Raku}}

{{libheader|ntheory}}

use warnings;

use ntheory 'primes';

print "\n\n 1000th: " . r_prime( 1000) . "\n";

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<pre>First 100:

{{libheader|Phix/online}}

You can run this online [http://phix.x10.mx/p2js/Ramanujan_primes.htm here].

<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>

<span style="color: #004080;">sequence</span> <span style="color: #000000;">pi</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>

<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"The %,dth Ramanujan prime is %,d\n"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">ramanujanPrime</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">)})</span>

<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>

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<pre>

All timings are purely informational. Will vary by system specs and load.

=== Pure Raku ===

use Lingua::EN::Numbers;

say "\n 1,000th: { comma 1000.&ramanujan-prime }";

say "10,000th: { comma 10000.&ramanujan-prime }";

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<pre>First 100:

=== ntheory library ===

{{libheader|ntheory}}

use Lingua::EN::Numbers;

}

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<pre>First 100:

<br>

This takes about 1.1 seconds to find the 100,000th Ramanujan prime on my machine. The millionth takes 13.2 seconds.

import "/seq" for Lst

import "/fmt" for Fmt

Fmt.print("\nThe 100,000th Ramanujan prime is $,9d", ramanujanPrime.call(100000))

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