Predefined Constants

There are several mytype constants defined when dd_set_global_constants(void) is called. Some constants depend on the double constant dd_almostzero which is normally set to $10^{-7}$ in cdd.h. This value can be modified depending on how numerically delicate your problems are but an extra caution should be taken.

mytype dd_purezero

:
This represents the mathematical zero $0$.

mytype dd_zero

:
This represents the largest positive number which should be considered to be zero. In the GMPRATIONAL mode, it is equal to dd_purezero. In the C double mode, it is set to the value of dd_almostzero.

mytype dd_minuszero

:
The negative of dd_zero.

mytype dd_one

:
This represents the mathematical one $1$.