Re: [Gretl-devel] [Gretl-users] pre-multiplication by transpose
On 12/08/2012 06:26 PM, Allin Cottrell wrote:
On Sat, 8 Dec 2012, Riccardo (Jack) Lucchetti wrote:
> This said, I think both expressions should be legal: in the
expressions "a'b"
> and "a' * b" the 'prime' character actually performs a
different role (as
> Allin already said): in the first case, it's shorthand for "transpose and
> then multiply"; in the second case, it means "transpose and see what
happens
> next".
>
> In the interest of common sense, I imagine that everybody agrees that
> transposition on a 1x1 matrix should be a no-op which takes precedence on
> anything else, so "a' * b" is exactly equivalent to "a*b".
For similar
> reasons, "a'b" should be interpreted as "since this is shorthand
for "(a')*b,
> just do the same".
I think you're right. That's now the situation in CVS.
sorry, I disagree. I can write more about this later, but IIUC now "a'b"
with for example "a" 1x1 and "b" 3x3 would not give an error and
multiply b with the scalar version of a. If that's so, I think this
would hide bugs in the hansl code which will be difficult to spot and
correct.
as I said, more thoughts later,
sven