#7539: primes.p0.spkg with "prime_sieve.c" functionality
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   Reporter:  GeorgSWeber    |       Owner:  rohana             
       Type:  enhancement    |      Status:  new                
   Priority:  major          |   Milestone:  sage-4.3           
  Component:  number theory  |    Keywords:                     
Work_issues:                 |      Author:  rohana, GeorgSWeber
   Upstream:  N/A            |    Reviewer:                     
     Merged:                 |  
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Comment(by kevin.stueve):

 It is appropriate to give credit to the sources I used in making the
 tables of offsets between prime_pi and a logarithmic integral
 approximation.  I used an asymptotic approximation to the logarithmic
 integral provided by Fredrik Johansson and the tables of prime_pi from
 http://www.primefan.ru/stuff/primes/table.html.  And the idea of combining
 a table of values of prime_pi and sieving for fast computation of the
 prime_pi was provided by the nth prime page at
 http://primes.utm.edu/nthprime/

 The primefan tables are extensive, and are from a combined effort of
 several individuals, including Andrey V. Kulsha, Anatoly F. Selevich, and
 Tomás Oliveira e Silva.  It is likely that the total computation time
 required to generate these tables was many processor years.

 As processor time (for the developer), hard-drive storage (for the
 client), and Internet bandwidth (for the client) become cheaper and more
 available, I would like to see published tables of prime_pi to expand (and
 to see resources put toward such computation).  It would be nice for the
 number of values in the prime_pi tables in Sage to increase every few
 years as the computation of the tables becomes easier for the developer
 and the download and storage of the tables becomes easier for the client.
 Maybe several table sizes could be offered.  A standard table could be the
 default for most users, but for those who are studying the distribution of
 prime numbers and desire speed over extra storage space on their hard-
 drive (and for bragging rights for Sage), larger tables could be offered.
 A web-service could even be offered to query a very large table of values
 of the prime counting function (the additional sieving could be done
 either on the server or client).  Of course, it would be very important to
 have redundancy in such large calculations (the generation of the prime_pi
 tables), as there have been incorrect values of the prime counting
 function published several times in the past.

 Kevin Stueve

-- 
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/7539#comment:1>
Sage <http://www.sagemath.org>
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