64 Basic Concepts of the Theory of Difference Schemes(x,t+r) (x-h,t+r) (x,t+r) (x+h,t+r
(x-h,t) ( x, t) (x+h,t) ( x, t)
a b(x-h,t+r) (x,t+r) (x+h,t+r)
(x-h,t) ( x, t) (x+h,t)
cFigure 4.is reasonable to place V:rx at the moment t + T, that is, on the upper layer,
so that(21) L(l) hT 1) -- Vt - Vx;x A ·By a linear combination of (19') and (21) we get a one-parameter family
of difference operators on the six-point pattern shown in Fig. 4.c for (} f- 0
and(} f- l:
(22)In the estimation of the order of approximation we substitute into the