Function: prodinf
Section: sums
C-Name: prodinf0
Prototype: V=GED0,L,p
Help: prodinf(X=a,expr,{flag=0}): infinite product (X goes from a to
 infinity) of real or complex expression. flag can be 0 (default) or 1, in
 which case compute the product of the 1+expr instead.
Wrapper: (,G)
Description:
  (gen,gen,?0):gen:prec prodinf(${2 cookie}, ${2 wrapper}, $1, $prec)
  (gen,gen,1):gen:prec prodinf(${2 cookie}, ${2 wrapper}, $1, $prec)
Doc: \idx{infinite product} of
 expression \var{expr}, the formal parameter $X$ starting at $a$. The evaluation
 stops when the relative error of the expression minus 1 is less than the
 default precision. In particular, divergent products result in infinite
 loops. The expressions must always evaluate to an element of $\C$.

 If $\fl=1$, do the product of the ($1+\var{expr}$) instead.

 \synt{prodinf}{void *E, GEN (*eval)(void*,GEN), GEN a, long prec}
 ($\fl=0$), or \tet{prodinf1} with the same arguments ($\fl=1$).
