Texas Instruments PLUS TI-89 - Manual (Page 483)

466 Appendix A: Functions and Instructions
8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 466 of 132
Loop CATALOG
Loop
block
EndLoop
Repeatedly executes the statements in block .
Note that the loop will be executed endlessly,
unless a
Goto or Exit instruction is executed
within block .
block is a sequence of statements separated
with the “:” character.
Program segment:
©
:1! i
:Loop
: Rand(6)! die1
: Rand(6)! die2
: If die1=6 and die2=6
: Goto End
: i+1! i
:EndLoop
:Lbl End
:Disp "The number of rolls is", i
©
LU MATH/Matrix menu
LU matrix , lMatName , uMatName , pMatName[ , tol]
Calculates the Doolittle LU (lower-upper)
decomposition of a real or complex
matrix .
The lower triangular matrix is stored in
lMatName , the upper triangular matrix in
uMatName , and the permutation matrix
(which describes the row swaps done during
the calculation) in
pMatName .
lMatName ù uMatName = pMatName ù matrix
Optionally, any matrix element is treated as
zero if its absolute value is less than
tol . This
tolerance is used only if the matrix has
floating-point entries and does not contain
any symbolic variables that have not been
assigned a value. Otherwise,
tol is ignored.
•
If you use ¥ ¸ or set the mode to
Exact/Approx=APPROXIMATE , computations
are done using floating-point arithmetic.
• If tol is omitted or not used, the default
tolerance is calculated as:
5 E л 14 щ max(dim( matrix ))
ù rowNorm( matrix )
The LU factorization algorithm uses partial
pivoting with row interchanges.
[6,12,18;5,14,31;3,8,18]!m1
¸



 6 12 18
5 14 31
3 8 18
LU m1,lower,upper,perm ¸ Done
lower ¸ 


 1 0 0
5/6 1 0
1/2 1/2 1
upper ¸ 


 6 12 18
0 4 16
0 0 1
perm ¸ 


 1 0 0
0 1 0
0 0 1
[m,n;o,p]!m1 ¸ [ ]
m n
o p
LU m1,lower,upper,perm ¸ Done
lower ¸ 


 1 0
m
o 1
upper ¸





 o p
0 n ì
møp
o
perm ¸ [ ]
0 1
1 0