From GridLAB-D Wiki
Double precision real values are represented using the double property type.
GLM
To declare a double value in a class use the syntax
class my_class { double my_double; }
You may include a unit with the declaration using the syntax
class my_class { double my_double[unit]; }
where unit is one of the supported units.
To define a double value in an object use the syntax
object my_class { my_double value; }
You may include units in the definition using the syntax
object my_class { my_double value unit; }
provided the units defined is compatible with the units declared.
ASCII formatting
The formatting of doubles is controlled by the double_format global variable.