|  |  7.10.6.25 ncrepIsDefinedDim Procedure from libraryncrat.lib(see  ncrat_lib).
 
Example:Usage:
list l = ncrepIsDefinedDim(q, N, vars, n, maxcoeff);
Return:
list(k, list vars, list(A1, ..., Ak)), where:
If k = N then there are matrices A1, ..., Ak of size N
such that q is defined at A = (A1, ..., Ak), i.e.,
 q.mat is invertible at A.
 If k = 0 then no such point was found.
 
Note:
Test whether q.mat is invertible via evaluation
at random matrix points with integer coefficients
 in [-maxcoeff, maxcoeff]. Stops after n tries.
 Use square matrices of dimension N. The list vars
 contains the nc variables which occur in q.
 
 |  | LIB "ncrat.lib";
ncInit(list("x", "y"));
ncrat f = ncratFromString("inv(x*y-y*x)");
ncrep q = ncrepGet(f);
ncrepIsDefinedDim(q, 1, list(x, y), 10, 100);
==> [1]:
==>    0
==> [2]:
==>    [1]:
==>       x
==>    [2]:
==>       y
==> [3]:
==>    empty list
ncrepIsDefinedDim(q, 2, list(x, y), 10, 100);
==> [1]:
==>    2
==> [2]:
==>    [1]:
==>       x
==>    [2]:
==>       y
==> [3]:
==>    [1]:
==>       _[1,1]=-55
==>       _[1,2]=-24
==>       _[2,1]=39
==>       _[2,2]=-17
==>    [2]:
==>       _[1,1]=36
==>       _[1,2]=-58
==>       _[2,1]=-13
==>       _[2,2]=-55
 | 
 
 |