The regulator of a number field is a positive number associated with
. The regulator of an imaginary
quadratic field is 1 and that of a real quadratic,
imaginary cubic, or totally imaginary cubic
field is the natural logarithm of the field's
fundamental unit, i.e.,
There is also a more complicated definition for a general number field as the determinant of an
matrix, where
has
real embeddings and
imaginary embeddings and
.
The regulator is implemented in the Wolfram Language for example as NumberFieldRegulator[Sqrt[d]].