HP15C Bug with MATRIX 5 Message #1 Posted by Thomas Klemm on 3 Feb 2012, 11:39 a.m.
So I was trying to use A^{T}B to calculate the scalar product of a vector with itself:
Definition of a 4x1 vector E
Set USER mode to enter the coordinates of the vector E = [1 2 3 4]^{T}:
4
ENTER
1
DIM E
MATRIX 1
1 STO E
2 STO E
3 STO E
4 STO E
Calculate E^{T}E
We'd expect that to be: 1^{2} + 2^{2} + 3^{2} + 4^{2} = 30.
RCL MATRIX E
RESULT A
ENTER
MATRIX 5
MATRIX 1
RCL A
And we get indeed:
30.0000
Running as a program
Use CLEAR PRGM to have all the programs removed. WARNING: you may not want to do that!
Now enter the few steps from above:
00142,26,11 RESULT A
002 36 ENTER
00342,16, 5 MATRIX 5
00442,16, 1 MATRIX 1
005^{u} 45 11 RCL A
And run the program:
RCL MATRIX E
RTN
R/S
I get an ERROR 11: Improper Matrix Argument. For MATRIX 5 the Appendix A: Error Conditions states as possible reasons:
 the input is a scalar;
 the dimensions are incompatible; or
 the result is one of the arguments.
The funny thing is that the result is there. The stack consists of the following values:
T:
Z: A 1 1
Y: 30.0000
X: 30.0000
But the program stopped at this line:
00342,16, 5 MATRIX 5
Workaround
A simple workaround is to add a RTN statement at the end of the program. Or you can singlestep through the program as well.
Now is this a well known bug of the HP15C? Could somebody verify this on a real calculator and possibly on the HP15C LE? Unfortunately I can only test this with an emulator.
Kind regards
Thomas
PS: You think I should use MATRIX 8 followed by x^{2} instead?
Edited: 3 Feb 2012, 11:44 a.m.
