Re: [SPOILER] Re: Euler problem #187

Luca Masini <lmasini@[EMAIL PROTECTED]
> writes Re: [SPOILER] Re: Euler problem #187

> Marcel Hendrix wrote:

>> Never forget the old but nonetheless excellent work of others (in this 
>> case Albert van der Horst).
> [SNIPPED]
>> --
--------------------------------------------------------------------------------------
>> 	INCLUDE ../benchmar/benchpin.frt \ PI(N2) ( n1 -- n2 ) counts all
primes below n1
> [SNIPPED]

> Is available the definition of PI(N2) ?

With Google, from Quartus' site
http://www.google.com/custom?q=benchpin&num=100&hl=en&lr=&safe=off&client=pub-9448921371862747&cof=S%3Ahttp%3A%2F%2Fquartus.net%2Fforth%3BCX%3AQuartus%252Enet%2520Forth%2520Search%2520Engine%3BL%3Ahttp%3A%2F%2Fquartus.net%2Fq.jpg%3BLH%3A48%3BLW%3A44%3BLP%3A1%3B&cx=008193674707816620280%3A1qayaf_i0fw

I found something faintly resembling it:

ftp://ccreweb.org/software/kforth/examples/benchmarks/benchpin.4th

> > Solution:
> > ---------
> > This is PI(n/i) - pi(i) + 1 for all primes i not greater than sqrt(n).

> In J is a one-liner
>    +/ (_1&p:@[EMAIL PROTECTED]
>.@[EMAIL PROTECTED]
(n%p:)-]) i._1&p:%:n [ n=:1e81742yyyy

> where _1&p: is the number of prime less than the argument ( PI(N2) )

It takes some getting used too, I guess :-)

> I'm trying to solve some problem using Forth now.

-marcel