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.
Doc: initialize tables for numerical summation using \kbd{sumnum} (with
 $\var{sgn}=1$) or \kbd{sumnumalt} (with $\var{sgn}=-1$), $sig$ is the
 abscissa of integration coded as in \kbd{sumnum}, and $m$ is as in
 \kbd{intnuminit}.
