Re: PARI-GP use of elldata & seadata packages

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Sun, Dec 04, 2011 at 10:42:18AM -0500, Alan Powell wrote:
> As a PARI-GP newbie, I could use a little help in installing 
> or activating the optional âelldataâ and âseadataâ packages.
> 
> I installed PARI-GP 2.5.0 running under Windows 7 SP1 and User 
> Guide examples seem to work normally.
> 
> I then downloaded, unzipped and copied the extra packages to the 
> PARI-GP (gp.exe) executable folder [C:\Program Files (x86)\PARI\] 
> as follows:
> 
> 1. A folder named elldata containing 200 files named ell0 thru ell199

This is normal.

> 2. A single file named seadata (no filename extension) size 39,870KB

It is not, it should be a directory with files sea0, sea2, sea211, etc.

> The User Guide elliptic functions seem to work e.g.
> 
> E = ellinit([0,0,0,-4,0])  outputs voluminous curve parameters
> 
> allap(E,11)  correctly outputs  = 0    but
> 
> ellidentify(E)  returns 
> 
> *** ellidentify: Elliptic curves files not available for conductor 64 
> [Missing C:/Program Files (x64)PARI/elldata/ell0].
> 
> [Note missing â/â between (x64) and âPARIâ]

I guess the code we use to get the directory where gp.exe is installed does not work
reliably on your system. Does "(x86)" really becomes "(x64)" ?

This is the code we use:

char* win32_datadir(void)
{
  char datadir[1024];
  char* slash;
  GetModuleFileNameA(0, datadir, sizeof(datadir) );
  slash = strrchr(datadir, '\\');
  if( slash ) *(slash+1) = 0;
  strcat(datadir, "data");
  return strdup(datadir);
}
Not sure what happen.

> trying example:
> 
> ellsea(E,nextprime(10^6))  returns
> 
> *** unknown function or error in formal parameters: elsea(E,97).

There is no ellsea function: the function is called ellap in both case.

Cheers,
Bill.