Re: Float Numbers with 200 digits

[Jacques Gélinas <jacquesg00@hotmail.com>]

> I need to know how to represent a float number in PARI

Here is the answer of professor GP2C from # gp2c-run tst.gp

========================= file tst.gp
x = 1e-100;
print("x = ",x);
=========================
========================= from file tst.gp.c
static GEN x;
/*End of global vars*/

void
init_tst(long prec)	  /* void */
{
  x = pol_x(0);
  x = strtor("1e-100", prec);
  pari_printf("x = %Ps\n", x);
  return;
}
================================
And this works!
================================
                GP/PARI CALCULATOR Version 2.12.1
$ init_tst()
x = 1.0000 E-100
$
================================

Jacques Gélinas










De : Loïc Grenié <loic.grenie@gmail.com>

Envoyé : 19 mai 2020 17:03

À : Tiago Mendes <tiagovazmendes7@gmail.com>

Cc : pari-users <pari-users@pari.math.u-bordeaux.fr>

Objet : Re: Float Numbers with 200 digits

 




    Hi,




On Tue 19 may 2020 at 04:10, Tiago Mendes wrote:


Hi guys,







I need to know how to represent a float number in PARI. To use integre i usually do :  



GEN expoent = strtoi("1123213137")






To represent a number like 10^{-200} how should i do ? 







     Depending on what you precisely need, real_1 might be your friend:



\fun{GEN}{real_1}{long prec} create a \typ{REAL} equal to $1$ to \kbd{prec}

words of accuracy.



    This creates a 1 with arbitrary precision. You can use it with
  gdiv(real_1(200),powuu(10,300)) (this creates 10^{-300} with 200 digits
  precision).



      Hope this helps,



             Loïc