Very Large Integers

[JohnNichols]

A few years ago we were talking about a package to handle large integers - say 200 long, I know it is here, but I cannot find it with a long search. 

Does someone remember the package?  

Thanks

[DavidWhite]

I found this article, but no code:

rpb042.pdf (anu.edu.au)

[DavidWhite]

And possibly this lead:

Fortran Software for Multiple Precision Arithmetic (lmu.build)

[Arjen_Markus]

The main page for that website contains links to the software - http://dmsmith.lmu.build/FMLIB.html

[JohnNichols]

Thank you.

The interesting challenge is that as soon as one starts working on math with integers you run out of large enough variables. 

@Arjen_Markus  do you have a program that access sql server from Fortran.  I thought I recognized your name on a web stie.  

I was looking to use SQL server to store and retrieve the prime number stuff, I spent two days trying to get an old FORDBC program to access any database.  The code is very painful and hidden in a library. 

It took 20 minutes last night in net. 

[JohnNichols]

I was just playing with the largest integer I can use in Intel Fortran.  I was just checking it with this program.  

!  Primer5.f90 
!
!  FUNCTIONS:
!  Primer5 - Entry point of console application.
!

!****************************************************************************
!
!  PROGRAM: Primer5
!
!  PURPOSE:  Entry point for the console application.
!
!****************************************************************************

    program Primer5

    use iso_fortran_env
    implicit none
    character*10 filename
    
    integer nprimemax
    integer(kind=selected_int_kind(15)):: i 
    integer sr 
    integer(kind=selected_int_kind(15)):: j15, j16
    sr = 15
    nprimemax = 2147483647
   ! nprimemax = 100000000
    
    filename = "Data.Txt"
    
    open(sr, file = filename, status = "UNKNOWN")
    
    j16 = huge(j15)
    do i = 1, j16
    
    if(mod(i,1000000000) == 0) then 
    write(*,*)i
    write(sr,*)i
    end if
    
    
    end do
     print *,'Selected Integer Kind 15:'
    print *, huge(j15)

    end program Primer5

it takes a few minutes to run on core i7 with an SSD. 

The huge int is the same as  taking a one metre step towards the moon and the largest Mersenne prime is 10% of the way to the moon - today. 

[Arjen_Markus]

Yes, that is me My main website Fortran-wise was for a long time http://flibs.sf.net, but recently I have become more active on Github. I wrote an ODBC interface that you might be able to use to connect to SQL Server. As I do not have access to it myself, I have no experience to share on that, but ODBC ought to be a useful method, once you have figured out the right connection string.

[JohnNichols]

I have FORDBC connected with the right string, the program retrieves all the table characteristics but it will not get the data.  

The connection string works and I get the data using .NET.  The jolly interesting thing is in mysql and net you just use a simple package and it works.  

My only problem is an intense lifelong dislike of C and so I will have to brush up on getting the C interface to work.  That is the problem with being taught Fortran and LISP as your first languages - after that the rest are just crappy to work with.  

I will give your code a try, thanks. 

Note: I watched the last Die hard movie last night, the computer stuff and the computer people were jolly fun, if you have not seen it, it is worth a look.