Denis Simon on Fri, 11 Dec 2020 18:06:16 +0100


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Re: Sum over prime numbers function

did you try vecsum in gp ?

Denis.

De: "Brereton, Ashley" <mf0u6084@liverpool.ac.uk>
À: "Bill Allombert" <Bill.Allombert@math.u-bordeaux.fr>, "pari-users" <pari-users@pari.math.u-bordeaux.fr>
Envoyé: Vendredi 11 Décembre 2020 18:01:52
Objet: Re: Sum over prime numbers function
I tried this and it's a smidge faster than prodeuler and I was hoping it would be much faster. Is there a vectorised way I can do this instead? e.g.

sum (primes(n))

I can't seem to find a way to sum a vector of values.

Thanks for your help!
Ash
From: Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>
Sent: Friday, December 11, 2020 2:48 AM
To: pari-users@pari.math.u-bordeaux.fr <pari-users@pari.math.u-bordeaux.fr>
Subject: Re: Sum over prime numbers function
 
On Fri, Dec 11, 2020 at 01:55:30AM +0000, Brereton, Ashley wrote:
> Hi all,
>
> I wondered if there was a handy function to sum over only the prime
> numbers? Like a sum version of prodeuler.

No. Instead you can use forprime:

my(s=0);forprime(p=2,100,s+=f(p));s

Cheers,
Bill.