[Gretl-devel] matrix transposition/multiplication operator precedence

Allin Cottrell cottrell at wfu.edu
Fri Jul 1 14:37:32 EDT 2016


On Fri, 1 Jul 2016, Sven Schreiber wrote:

> Hi,
> not sure if this is a bug:
>
> <hansl>
> matrix a = zeros(3,1)
> matrix b = ones(2,3)
>
> matrix hu = a' * b'
> hu = a'(b')
> hu = a'b'	# fails
> </hansl>
>
> Apparently gretl interprets the last line as "(a'b)'" which kind of implies 
> that the implicit multiplication with the transpose sign has higher 
> precedence than the actual transposition of b.

"Kind of". But couldn't this be interpreted as a case of simple 
left-to-right evaluation in the absence of another deciding 
criterion?

Off the cuff, I'd be inclined to say that it's a bug only if one 
reckons that the correct behavior is to reject the expression as 
ambiguous.

Allin



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