# Singular

#### D.11.4.3 difpoly2tex

Procedure from library findifs.lib (see findifs_lib).

Usage:
difpoly2tex(S,P[,Q]); S an ideal, P and optional Q are lists

Return:
string

Purpose:
present the difference scheme in the nodal form

Assume:
ideal S is the result of decoef procedure

Note:
a list P may be empty or may contain parameters, which will not appear in denominators
an optional list Q represents the part of the scheme, depending on other function, than the major part

Example:
 LIB "findifs.lib"; ring r = (0,dh,dt,V),(Tx,Tt),dp; poly M = (4*dh*Tx+dt)^2*(Tt-1) + V*Tt*Tx; ideal I = decoef(M,dt); list L; L[1] = V; difpoly2tex(I,L); ==> \frac{1}{8\tri t}\cdot (u^{n+1}_{j+2}-u^{n}_{j+2}+\frac{\nu}{16\tri h^{2}\ } u^{n+1}_{j+1})+ \frac{1}{16\tri h}\cdot (u^{n+1}_{j+1}-u^{n}_{j+1}+\fra\ c{\tri t}{8\tri h} u^{n+1}_{j}+\frac{-\tri t}{8\tri h} u^{n}_{j}) poly G = V*dh^2*(Tt-Tx)^2; difpoly2tex(I,L,G); ==> \frac{1}{8\tri t}\cdot (u^{n+1}_{j+2}-u^{n}_{j+2}+\frac{\nu}{16\tri h^{2}\ } u^{n+1}_{j+1})+ \frac{1}{16\tri h}\cdot (u^{n+1}_{j+1}-u^{n}_{j+1}+\fra\ c{\tri t}{8\tri h} u^{n+1}_{j}+\frac{-\tri t}{8\tri h} u^{n}_{j})+ \frac{\ \nu}{128\tri t}\cdot (p^{n}_{j+2}+(-2) p^{n+1}_{j+1}+p^{n+2}_{j})