getNonUnit -- retrieve a previously discovered non-unit

getNonUnit -- retrieve a previously discovered non-unit

Synopsis:

Usage: r = getNonUnit R

Input:

R: a ring in which division by a non-unit has been attempted

Output:

r: the non-unit

Warning: this function does not work yet for divisions attempted in the course of computing a Groebner basis or resolution.

See also:

toField -- declare that a ring is a field

getZeroDivisor -- retrieve a previously discovered zero divisor

Code:

     -- ../../../Macaulay2/m2/quotring.m2:303-310
     getNonUnit = R -> (
          if R.?nonUnit then R.nonUnit
          else if R.?Engine and R.Engine then (
               sendgg(ggPush R, gggetzerodivisor);
               r := R.pop();
               if r != 0 then r
               )
          )