Solving a maths problem with Perl

Simple maths problem.

a_n is defined as 1 + (1/n).

S_n is defined as a₁ + a₂ + ... + a_n.

So we're gonna calculate S₁₅, and we're gonna use object-oriented programming because I'm me.

use v5.16;

package Local::App {
    use Zydeco;
    use List::Util 'sum';

    class Calc {
        method a ( PositiveInt $n ) = 1 + (1/$n);
        method S ( PositiveInt $n ) = sum( map $self->a($_), 1 .. $n )
+;
    }
}

my $calc = Local::App->new_calc;
say $calc->S(15);
[download]

Or, using rational numbers:

use v5.16;

package Local::App {
    use Zydeco;
    use List::Util 'sum';

    class Calc {
        method r ( $n ) = 1/$n;
        method a ( PositiveInt $n ) = 1 + $self->r($n);
        method S ( PositiveInt $n ) = sum( map $self->a($_), 1 .. $n )
+;
        
        class +Rational {
            use Math::BigRat;
            method r ( $n ) = Math::BigRat->new("1/$n");
        }
    }
}

my $calc = Local::App->new_calc_rational;
say $calc->S(15);
[download]

toby döt ink

Comment on Solving a maths problem with Perl Select or Download Code

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Re: Solving a maths problem with Perl by tobyink (Canon) on Sep 03, 2020 at 11:30 UTC
And yes, I'm aware it can be solved without object-oriented programming. `use v5.16; package Local::App2 { use List::Util 'sum'; use Exporter::Shiny 'S'; sub a { my $n = shift; 1 + (1/$n); } sub S { my $n = shift; sum( map a($_), 1 .. $n ); } } use Local::App2 'S'; say S(15);` [download] I like using OOP though because of the ease with which parts can be overridden, like in the rational number version. toby döt ink	[reply] [d/l]
Re: Solving a maths problem with Perl by etj (Priest) on Aug 10, 2024 at 05:18 UTC
And because I, in turn, am me: `pdl> $n = sequence(15)+1 pdl> p $a = 1 + 1/$n [2 1.5 1.33333333333333 1.25 1.2 1.16666666666667 1.14285714285714 1.1 +25 1.11111111111111 1.1 1.09090909090909 1.08333333333333 1.076923076 +92308 1.07142857142857 1.06666666666667] pdl> p $s = $a->sumover 18.318228993229` [download] I'm somewhat sure that took less time and was more maths-y than using OO ;-)	[reply] [d/l]
Re^2: Solving a maths problem with Perl by marioroy (Prior) on Aug 10, 2024 at 07:54 UTC
I tried combining tobyink's OOP and your solution ;-) `use v5.16; package Local::App2 { use Exporter::Shiny 'S'; use PDL; sub a { my $n = shift; my $pdl = sequence($n) + 1; my $ans = 1 + (1/$pdl); } sub S { my $n = shift; my $s = a($n)->sumover; } } use Local::App2 'S'; say S(15);` [download] Output `18.318228993229` [download]	[reply] [d/l] [select]
Re: Solving a maths problem with Perl by perlfan (Parson) on Sep 30, 2020 at 19:08 UTC
>because I'm me. I must say that I, for one, find all the oop modules you're churning out very interesting and fun to watch.	[reply]