Texas Instruments TI-89 - Push_Factorial

784
Appendix A: System Routines — Math
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
push_factorial
Declaration:
void
push_factorial
(EStackIndex
i
)
Category(ies):
Math
Description:
Pushes the internally-simplified factorial of the expression indexed by
i
.
Although z! = Gamma(z - 1) for all complex z, where Gamma is the Euler
Gamma function, this implementation of factorial computes a numeric
result only for non-negative integer z.
Inputs:
i
— Indexes the top tag of an algebraic expression, an algebraic
comparison, or an aggregate thereof.
Outputs:
None
Assumptions:
None
Side Effects:
None
Availability:
On AMS 2.02 and higher.
TI
-
89 / TI
-
92 Plus
Differences:
None
See Also:
None
Example:
If
i
indexes a negative integer, then
push_factorial
(
i
) pushes
PLUS_OR_MINUS_INFINITY_TAG.
If
i
indexes IM_RE_TAG or PI_TAG, then
push_factorial
(
i
) pushes
FACTORIAL_TAG on top of a copy of the expression indexed by
i
.
push_quantum_as_nonnegative_int (3u);
push_factorial (top_estack); /* Pushes a tagged integer 6 */