Texas Instruments TI-89 - Get_Lb

470
Appendix A: System Routines — EStack Arithmetic
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
get_lb
Declaration:
float
get_lb
(EStackIndex
var
)
Category(ies):
EStack Arithmetic
Description:
If global
NG_such_that_index
includes
var
>= expression, and
approx (expression) -> float, returns that float. Otherwise if global
NG_such_that_index
includes
var
> expression, and approx (expression)
-> float, returns that float
N
epsilon, where epsilon = 1E-38 if approx (x) ==
0.0 or 8
†
FLOAT_EPSILON
†
ABS (Float) if approx (x) != 0.0. Otherwise
returns FLOAT_MAX.
Inputs:
var
— Index of a variable.
Outputs:
None
Assumptions:
None
Side Effects:
None
Availability:
On AMS 2.02 and higher.
TI
-
89 / TI
-
92 Plus
Differences:
None
See Also: get_ub
Example:
Int var_gt_eq_other_const (EStackIndex ki, EStackIndex j)
/* ki indexes a kernel and j indexes a number.
Using NG_such_that_index:
returns 1 if deduces the variable indexed by ki > the number indeded by j,
returns 0 if deduces the variable indexed by ki = the number indeded by j,
returns -1 otherwise.
*/
{ Access_AMS_Global_Variables;
Float fki = get_lb (ki);
if (fki < FLOAT_MAX)
{ ki = top_estack;
push_approx (j);
j = top_estack;
if (FLOAT_TAG == ESTACK (j))
{ Float fj = ESTACK_TO_FLOAT (j);
top_estack = ki;
return fki < fj ? -1 : fki > fj;
}
}
return -1;
}