Dyalog Forums

especially useful when ... iterating ... array operands Thanks for that Adam. I've tried and, I think, succeeded in doing that but always more long-winded by demoting the array operand as an argument to reduction applied to an inner dop rather than linking it with a recursive call to the dop itself ...

I never could find a requirement for that - though I did try - perhaps Adam may have done?

Apologies for lack of diacritic Adam.

Again without recourse to actually trying it I don't believe your suggestion would be possible to reference the outside dop from a nested dfn therein. Or let's say it may be possible because no-one ever got round to writing code that would prevent it but remembering what I do of JS's hopes and aims ...

Hey Paul Without reference to the reference this is the way I look at it. First off and without trying it I think that within a dfn ∇∇ has no meaning. But within a dop , as within a dfn , ∇ means the current function . So within a dop it's not a reference to itself but to the derived function; that i ...

In fact decode works not on rank 2 but on the first dimension. The fact that reduction works on the last dimension is a mistake or oversight made in the earliest impementations and only corrected by Ken and Roger when they implemented J.

So the why is history.

The rank operator applies its left function operand to cells of its arguments defined by the ranks in its right vector operand. so in this case 1-cells (rows) in each argument are paired. As there is only one 1-cell in x it is repeated for each in y

Your target result implies that you actually want the length of the vector and width of the matrix to conform which seems to be contradicted by the final sentence. However

x ×⍤1⊢ y

will give the answer.

corrected immediately PL

Well done and thank you Ray.
And a fine holiday season to you.

Somewhere in ⎕SE there has been created a namespace (or object or an array that contains such) that is a reference to # or a namespace within it. If you have a non-empty )si stack then )clearing it might well remove the problem because the reference will almost certainly be localised in one of the ⎕ ...

My apologies to Adam if I misconstrued his

so you can edit more arrays than currently possible (just text arrays).

On rereading it I see that the parenthesis applies to the current limitation, not the enhancement.