Is_Real - Texas Instruments TI-89 Developer's Manual

734

is_real

Declaration: Boolean is_real (EStackIndex i )
Category(ies): Logic
Description: Determine whether the internally-simplified algebraic expression indexed
by i is real for all finite real values of all variables therein.
i
Inputs:
Outputs: Returns TRUE if it can determine that the internally-simplified algebraic
expression indexed by i is real for all finite real values of all variables
therein. Otherwise returns FALSE, even though the expression might
always be real.
Assumptions: None
Side Effects: None
Availability: On AMS 2.02 and higher.
TI-89 / TI-92 Plus
Differences: None
See Also: None
Example:
void push_real_factors (EStackIndex i)
/* Pushes the product of the decidably real factors of i. */
{ if (MULTIPLY_TAG == ESTACK (i))
{ push_real_factors (next_expression_index (--i));
if (is_real (i))
times_top (i);
}
else if (is_real (i))
push_expression (i);
else
push_expression (Integer1Index);
}
TI-89 / TI-92 Plus Developer Guide
— Index of the top tag of an internally-simplified expression or an
aggregate thereof.
Not for Distribution
Appendix A: System Routines — Logic
Beta Version January 26, 2001