Home primes: Difference between revisions

=={{header|Factor}}==

{{works with|Factor|0.99 2021-02-05}}

math.primes.factors math.ranges present prettyprint sequences

sequences.extras ;

: chain. ( n -- ) dup prime? [ prime. ] [ multi. ] if ;

 

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<pre>

{{trans|Wren}}

{{libheader|Go-rcu}}

 

import (

}

}

 

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=={{header|J}}==

hseq =: [,$:@step`(0&$)@.(1&p:)

fmtHP =: (' is prime',~":@])`('HP',":@],'(',":@[,')'&[)@.(*@[)

printHP =: 0 0&$@stdout@(fmtlist@hseq,(10{a.)&[)

printHP"0 [ 2}.i.21

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<pre>2 is prime

 

=={{header|Julia}}==

 

function homeprimechain(n::BigInt)

printHPiter(i)

end

<pre>

Home Prime chain for 2: 2 is prime.

 

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

HP[n_] := FromDigits[Catenate[IntegerDigits /@ Sort[Catenate[ConstantArray @@@ FactorInteger[n]]]]]

HPChain[n_] := NestWhileList[HP, n, PrimeQ/*Not]

Row[Prepend["Home prime chain for " <> ToString[#] <> ": "]@Riffle[HPChain[#], ", "]] & /@ Range[2, 20] // Column

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<pre>Home prime chain for 2: 2

{{libheader|bignum}}

This algorithm is really efficient. We get the result for HP2 to HP20 in about 6 ms and adding HP65 in 1.3 s. I think that the threshold to switch to Pollard-Rho is very important.

import bignum

 

break

else:

 

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=={{header|Perl}}==

{{libheader|ntheory}}

use warnings;

use ntheory 'factor';

else { print "HP$m = " }

print "$steps[-1]\n";

 

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=={{header|Phix}}==

Added a new mpz_pollard_rho routine, based on the [[wp:Pollard%27s_rho_algorithm]] C code.

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

<span style="color: #7060A8;">requires</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1.0.0"</span><span style="color: #0000FF;">)</span>

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

<span style="color: #7060A8;">papply</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #000000;">20</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)&</span><span style="color: #000000;">65</span><span style="color: #0000FF;">,</span><span style="color: #000000;">test</span><span style="color: #0000FF;">)</span>

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Using underscores to show the individual factors that were concatenated together

Using [https://modules.raku.org/search/?q=Prime+Factor Prime::Factor] from the [https://modules.raku.org/ Raku ecosystem].

 

 

my $start = now;

$now = now;

last if $step > 30;

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<pre>HP2 = 2 (0.000 seconds)

 

=={{header|REXX}}==

numeric digits 20 /*ensure handling of larger integers. */

parse arg LO HI . /*obtain optional arguments from the CL*/

/* [↓] The $ list has a leading blank.*/

if x==1 then return $ /*Is residual=unity? Then don't append.*/

{{out|output|text=&nbsp; when using the default input:}}

<pre>

 

=={{header|Sidef}}==

 

var steps = []

 

say ("HP(#{orig}) = ", steps.map { .join('_') }.join(' -> '))

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<pre>

 

Reaches HP20 in about 0.52 seconds but HP65 took just under 40 minutes!

import "/big" for BigInt

}

}

 

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{{libheader|Wren-gmp}}

This reduces the overall time taken to 5.1 seconds. The factorization method used is essentially the same as the Wren-cli version so the vast improvement in performance is due solely to the use of GMP.

 

import "./gmp" for Mpz

}

}

 

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