|  |  7.5.4.0. Sannfs Procedure from librarydmod.lib(see  dmod_lib).
 
Example:Usage:
Sannfs(f [,S,eng]); f a poly, S a string, eng an optional int
Return:
ring
Purpose:
compute the D-module structure of basering[f^s] with the algorithm
given in S and with the Groebner basis engine given in eng
 
Note:
activate the output ring with the setringcommand.The value of a string S can be
 'bm' (default) - for the algorithm of Briancon and Maisonobe,
 'lot' - for the Levandovskyy's modification of the algorithm of OT,
 'ot' - for the algorithm of Oaku and Takayama.
 If eng <>0,
 stdis used for Groebner basis computations,otherwise, and by default
 slimgbis used.In the output ring:
 - the ideal LD is the needed D-module structure.
 
Display:
If printlevel=1, progress debug messages will be printed,if
 printlevel>=2, all the debug messages will be printed.
 |  | LIB "dmod.lib";
ring r = 0,(x,y,z),Dp;
poly F = x^3+y^3+z^3;
printlevel = 0;
def A  = Sannfs(F); // here, the default BM algorithm will be used
setring A;
LD;
==> LD[1]=z^2*Dy-y^2*Dz
==> LD[2]=x*Dx+y*Dy+z*Dz-3*s
==> LD[3]=z^2*Dx-x^2*Dz
==> LD[4]=y^2*Dx-x^2*Dy
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