Hi,
when I'm feeling really nerdy I try to use qform() instead of directly
writing the matrix product Z'Z. But since qform() is of course actually
for x*A*x', I have to insert an identity matrix as the second argument,
like this:
qform(x', I(cols(x)))
So two questions:
1) Is it actually really faster to use qform() for this kind of inner
product where A is the identity matrix? (I know the speed difference
won't be noticeable anyway, but in theory.)
2) If the answer is yes, could qform() be generalized such that the
second argument is optional and defaults to a conformable identity
matrix? Then we could write qform(x') for x'x.
2b) Actually it now occurs to me: with this mysterious but indoubtedly
great new syntax parser that gretl has, could gretl be clever enough to
spot occurrences of x'x and internally execute that as qform(x')? (Still
provided the answer to 1 is yes.)
thanks,
sven