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

Step-by-step operations

 

storage.

 

ENVSTACK

Flags and current path.

PUSH, POP

EPS

Maximum coefficient to

EPSX0

 

round to zero.

 

IERR

Error of integration

Numerical integration

 

 

operations

MODULO

The current modulus.

MOD functions

PERIOD

Period for periodic

Various CAS operations

 

operations.

 

PRIMIT

Anti-derivative temporary

Various CAS operations

 

storage.

 

REALASSUME

List of variables to treat as

Various CAS operations

 

real numbers in complex

 

 

mode.

 

VX

Default variable for symbolic

Various CAS operations

 

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.

Reserved Variables D-13