You are right but it is a bit of serendipity What I wanted is (a*b+
b*c+c*a ) % c a b .
it doesn't matter how the pairs are formed in the numerator ac+ba+cb is
the same.
The objective is to have this sum divided by a c b a orde.r
The problem is in the notation. Single subscripts due to singular values
are not adequate ( so the rotation is needed to preserve order of
terminals in considering the physical setup of impedance elements
connected in a triangular (delta or Pi) mode and the equivalent Y or T
connection between the same terminals(consider 3 terminals connected in
a Delta or triangle vs a connection iin a Y between the same terminals
I have done some timing and space analysis which, while of no practical
meaningfulness for this particular situation , does indicate tmy
original explicit approach suffers greatly compared to a tacit version
and the automatically generated tacit version is not as effective as
"designed" versions such as yours. I will post these comparisons but
right now, bedtime and an excess of wine loom
Don Kelly
On 26/10/2013 3:23 PM, Mike Day wrote:
Is this the sort of thing you wanted?
It's worth noting that _1 |. y and 2 0 1 { y yield the same result,
so you don't need to use both forms in ytodel
deltoya =: (*_1&|.)%+/ NB. not tested for edge
effects.....
ytodela=: ( +/@:* %] ) _1&|.
deltoya ytodela 1j2 2j1 3
1j2 2j1 3
ytodela deltoya 1j2 2j1 3
1j2 2j1 3
Mike
On 26/10/2013 04:36, Don Kelly wrote:
I have written a couple of explicit verbs for Y-delta network
transforms and would like advice on how to express them in a tacit form.
This is for my learning benefit as the use of these comes up only
occasionally and input and output are always only 3 numbers.
deltoy=:3 : '(y*_1|.y)%+/y' from Delta to Wye
ytodel =:3 : '(+/(y*_1|.y))% 2 0 1{y' Wye to Delta
input and output are of the form zij =: a b c where a bc may be real
or complex
my problem is getting around the multiple use of y I suspect that a
train of forks might work but haven't got it yet.
In addition is there an easier way to obtain pairs a*b b*c and c*a
than what I have used?
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm
