Function: sumnuminit
Section: sums
C-Name: sumnuminit
Prototype: GD0,L,D1,L,p
Help: sumnuminit(sig, {m=0}, {sgn=1}): initialize tables for numerical
 summation. sgn is 1 (in fact >= 0), the default, for sumnum (ordinary sums) 
 or -1 (in fact < 0) for sumnumalt (alternating sums). sig is as in sumnum and
 m is as in intnuminit.

