Reference Guide

Reserved Variables D-13
CASDIR Reserved Variables
The Computer Algebra System stored its reserved variables in a special directory called CASDIR.
Reserved Variable What It Contains Used By
CASINFO Graphic display temporary
storage.
Step-by-step operations
ENVSTACK Flags and current path. PUSH, POP
EPS Maximum coefficient to
round to zero.
EPSX0
IERR Error of integration Numerical integration
operations
MODULO The current modulus. MOD functions
PERIOD Period for periodic
operations.
Various CAS operations
PRIMIT Anti-derivative temporary
storage.
Various CAS operations
REALASSUME List of variables to treat as
real numbers in complex
mode.
Various CAS operations
VX Default variable for symbolic
operations.
Various CAS operations
Contents of the CASDIR Reserved Variables
CASINFO
CASINFO provides temporary storage for the graphic display during step-by-step operations.
ENVSTACK
ENVSTACK is a variable stored in the CAS directory. It is used by PUSH and POP to save the status of flags and
the current directory. (PUSH saves the data in ENVSTACK; POP restores it.)
EPS
EPS contains a real number specifying that coefficients in a polynomial smaller than this value are replaced with 0.
It is used by the EPSX0 command. The default value is 1E-10.
IERR
IERR contains the error tolerance of integration during numeric integration.