<DOC>
<DOCNO>
1079
</DOCNO>
<TITLE>
finite difference formulae for the square lattices .
</TITLE>
<AUTHOR>
nicley,w.g.
</AUTHOR>
<BIBLIO>
q.j.mech. app. math, 1, p35.
</BIBLIO>
<TEXT>
  the paper gives approximate formulae
for derivatives (including combinations
like and ), and integrals, of a function
of two independent variables, in terms
of its values at nodes of a square lattice,
primarily for use in the numerical solution
of partial differential equations .  consideration
is given to the form, as well as to
the magnitude, of the leading terms in the
error, and what is believed to be for
most purposes optimum combinations are
thus selected for the simpler compact
sets of nodes .
</TEXT>
</DOC>
