Re: HP49G VectorMatrix Multiplication Message #7 Posted by Karl Schneider on 10 Feb 2006, 1:05 a.m., in response to message #6 by William
William 
You're in luck  I also happen to have an HP49G, so was able to try your example. (I should point out that in RPL, it's {data} 'A' STO, not {data} STO 'A'...)
I follow the example  it looks to me like a rowvector A and a square matrix B. The vector entered with a single set of brackets on one line even looks like a row vector in the Matrix Editor.
But, when multiplying them with 'A' above 'B' in the stack, I get the same dimension error. Marcus von Cube's post has the fix: Make 'A' a true row vector by enclosing it within an extra set of brackets. ("TRAN" will also transpose a matrix or vector on the 49G.) I noticed that, for whatever reason, the transpose made no difference in the vector's layout in Matrix Editor.
[14 14 14]^{T} is the product B*A^{T}  i.e., the matrix times the column vector.
I struggled to get my 48G to do what I wanted in this example, also.
How counterintuitive! This deepens my appreciation for the HP15C and HP42S, both of which I would trust far more than any RPL model to use on an important exam.
 KS
