Section 12: Calculating with Matrices 171
Keystrokes
Display
´>
2
A
4
4
Transforms
A
P
into
Ã
.
´<
C
A
4
4
Designates matrix
C
as
result matrix.
÷
C
4
1
Calculates
X
P
and stores
in
C
.
|c
C
2
2
Transforms
X
P
into
X
C
.
lC
0.0372
Recalls
c
11
.
lC
0.1311
Recalls
c
12
.
lC
0.0437
Recalls
c
21
.
lC
0.1543
Recalls
c
22
.
´U
0.1543
Deactivates User mode.
´>
0
0.1543
Redimensions all matrices
to 0×0.
The currents, represented by the complex matrix
X
, can be derived from
C
i
i
I
I
2
1
0.1543
0.0437
0.1311
0.0372
X
Solving the matrix equation in the preceding example required 24 registers
of matrix memory – 16 for the 4×4 matrix
A
(which was originally entered
as a 4×2 matrix representing a
2×2
complex matrix), and four each for the
matrices
B
and
C
(each representing a 2×1 complex matrix). (However, you
would have used four fewer registers if the result matrix were matrix
B.
)
Note that since
X
and
B
are not restricted to be vectors (that is, single-
column matrices),
X
and
B
could have required more memory.
The HP-15C contains sufficient memory to solve, using the method
described above, the complex matrix equation
AX
=
B
with
X
and
B
having
up to six columns if
A
is 2×2, or up to two columns if
A
is 3×3.
*
(The
allowable number of columns doubles if the constant matrix
B
is used as the
result matrix.) If
X
and
B
have more columns, or if
A
is 4×4, you can solve
the equation using the alternate method below. This method differs from the
preceding one in that it involves separate inversion and multiplication
operations and fewer registers.
*
If all available memory space is dimensioned to the common pool (
W
:
1 64 0-0
). Refer to appendix C,
Memory Allocation.
Summary of Contents for HP-15C
Page 1: ...HP 15C Owner s Handbook HP Part Number 00015 90001 Edition 2 4 Sep 2011 ...
Page 17: ...Part l HP 15C Fundamentals ...
Page 64: ......
Page 65: ...Part ll HP 15C Programming ...
Page 118: ...118 ...