Top
Back: testParametrization
Forward: resbinomial_lib
FastBack:
FastForward:
Up: paraplanecurves_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.5.4.11 testPointConic

Procedure from library paraplanecurves.lib (see paraplanecurves_lib).

Usage:
testPointConic(p, r); p poly, r ring

Assume:
assumes that p is a homogeneous quadratic polynomial in the first three ring variables of the current basering;
Assumes that there is a (1x3) matrix named 'point' in r with entries from the ground field of r.

Return:
returns 1 iff the point named 'point', residing in r, lies on the conic given by p; 0 otherwise

Note:
This method temporarily changes the basering to r. Afterwards, the basering will be the same as before.

Example:
 
LIB "paraplanecurves.lib";
ring R = 0, (x,y,z), dp;
system("random", 4711);
poly p = x^2 + 2*y^2 + 5*z^2 - 4*x*y + 3*x*z + 17*y*z;
def S = rationalPointConic(p);
if (testPointConic(p, S) == 1)
==> conic: x2-4xy+2y2+3xz+17yz+5z2
==> point: (-1/4a), (-1/4a+1/4), 0
==> minpoly: (a2-2)
{ "point lies on conic"; }
==> point lies on conic
else
{ "point does not lie on conic"; }

Top Back: testParametrization Forward: resbinomial_lib FastBack: FastForward: Up: paraplanecurves_lib Top: Singular Manual Contents: Table of Contents Index: Index About: About this document
            User manual for Singular version 4-0-3, 2016, generated by texi2html.