Michael Somos on Fri, 29 Oct 1999 15:22:09 -0400 (EDT)

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abs() documentation bug

                    GP/PARI CALCULATOR Version 2.0.17 (beta)
                i686 running linux (ix86 kernel) 32-bit version
              (readline v2.2 enabled, extended help not available)

                           Copyright (C) 1989-1999 by
          C. Batut, K. Belabas, D. Bernardi, H. Cohen and M. Olivier.

Type ? for help, \q to quit.
Type ?12 for how to get moral (and possibly technical) support.

   realprecision = 28 significant digits
   seriesprecision = 16 significant terms
   format = g0.28

parisize = 4000000, primelimit = 500000
gp> abs(x-x^2)
%1 = x^2 - x
gp> abs(x-x^2+O(x^3))
  ***   incorrect type in gabs.
gp> ??abs

   absolute value of x (modulus if x is complex). Polynomials, power series and
rational functions are not allowed.  Contrary to most transcendental functions,
an integer is not converted to a real number before applying abs.

   The library syntax is gabs(x,prec).

The documentation indicates that polynomials are not allowed, but the
example shows that this is not true. It even might produce a useful
result. However, this should be documented. Shalom, Michael

Michael Somos <somos@grail.cba.csuohio.edu>     Cleveland State University
http://grail.cba.csuohio.edu/~somos/            Cleveland, Ohio, USA 44115