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7.10.6.32 ncrepPencilGet
Procedure from library ncrat.lib (see ncrat_lib).
- Usage:
- list pencil = ncrepPencilGet(r, vars);
- Return:
- pencil = list(vars, matrices),
where vars = list(1, x1, ..., xg) are the variables
occurring in r and matrices = (Q0, ..., Qg) is a list of
matrices such that
r.mat = Q0 * x0 + ... + Qg * xg
with x0 = 1
- Note:
- list vars = list(x1, ..., xn) has to consist
exactly of the nc variables occurring in f
Example:
| | LIB "ncrat.lib";
ncInit(list("x", "y"));
ncrat f = ncratFromString("x*y");
ncrep r = ncrepGet(f);
print(r.mat);
==> 0, 0, x, -1,
==> 0, 1, -1,0,
==> y, -1,0, 0,
==> -1,0, 0, 0
list l = ncrepPencilGet(r, list(x, y));
print(l[1]);
==> [1]:
==> 1
==> [2]:
==> x
==> [3]:
==> y
print(l[2][1]);
==> 0, 0, 0, -1,
==> 0, 1, -1,0,
==> 0, -1,0, 0,
==> -1,0, 0, 0
print(l[2][2]);
==> 0,0,1,0,
==> 0,0,0,0,
==> 0,0,0,0,
==> 0,0,0,0
print(l[2][3]);
==> 0,0,0,0,
==> 0,0,0,0,
==> 1,0,0,0,
==> 0,0,0,0
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