HP HP-15C Advanced Functions Handbook

150
Section 4: Using Matrix Operations
QrAQ is not close enough to diagonal, it is used in place of A above
for a repetition of the process.
In this way, successive orthogonal transformations Q1; Q2, Qa, ...
are applied to A to produce a sequence A1( A2, A3,..., where
A;-(Q1Q2...Q/AQ1Q2...Q;
with each successive Ay more nearly diagonal than the one before.
This process normally leads to skew matrices whose elements are
all small and A; rapidly converging to a diagonal matrix A.
However, if some of the eigenvalues of matrix A are very close but
far from the others, convergence is slow; fortunately, this situation
The program stops after each iteration to display
I off-diagonal elements of A;-| / 1| A.j\\
which measures how nearly diagonal is Ay. If this measure is not
negligible, you can press |R/S| to calculate A.j+i; if it is negligible,
then the diagonal elements of Ay approximate the eigenvalues of A.
The program needs only one iteration for 1X1 and 2X2 matrices,
and rarely more than six for 3X3 matrices. For 4X4 matrices the
program takes slightly longer and uses all available memory;
usually 6 or 7 iterations are sufficient, but if some eigenvalues are
very close to each other and relatively far from the rest, then 10 to
16 iterations may be needed.
Keystrokes
Display
000-
001-42,21,11
002-45,16,11
003-44,16,12
004-44,16,13
005-42,16, 4
006-45,16,12
007- 44 26
008- 40
Program mode.
Dimensions B.
Dimensions C.
Transposes A.

HP HP-15C Specifications

General

Brand	HP
Model	HP-15C
Category	Calculator
Language	English