forceGB(..., ChangeMatrix => ...) -- inform Macaulay2 about the change of basis matrix from GB to generators

Synopsis

Usage:
forceGB(...,ChangeMatrix=>m)
Inputs:
- m, a matrix
Consequences:
- Set the change of basis matrix from the Groebner basis to the original generators

The matrix m should have size a by b, where a is the number of columns of the original matrix, and b is the number of columns of f.

i1 : gbTrace = 3

o1 = 3

i2 : R = ZZ[x,y,z];

i3 : f = matrix{{x^2-3, y^3-1, z^4-2}};

             1       3
o3 : Matrix R  <--- R

i4 : g = forceGB(f, ChangeMatrix=>id_(source f));

i5 : x^2*y^3 // g

   -- ..
o5 = {2} | y3 |
     {3} | 3  |
     {4} | 0  |

             3       1
o5 : Matrix R  <--- R