Re: gridding: differences of 4.2 and 4.4

[Philipp K. J. <ja...@ie...>]

It was me who wrote the code for the "new" dgrid3d 
function, a couple of years back. I am just looking at
the code and trying to get back into what I tried to do.

>
> Could someone please clarify:
>
> - The BNF description of syntax under "help set dgrid3d" shows
>   only the "hann" option taking 2 additional parameters.
>   But the text says that 5 options use these parameters.
>   Which is correct?

All of the "new" smoothing kernels take the same number
of parameters. There is a set of square brackets missing
in the doc. (My bad.)

>
> - Is there a difference between
> 	set dgrid3d <rows>, <cols>, <norm>        # old syntax
>   and
> 	set dgrid3d <rows>, <cols>, <norm> qnorm  # is this legal?

This should not be legal. (But it might work - got to try.)

>   and
> 	set dgrid3d <rows>, <cols> qnorm <norm>   # new syntax

This should be identical to the first.

>
> - Note that the current BNF description of syntax would not allow
>   either of the first two commands above

That is correct. The synopsis shows only the new form
of the command, which makes the kernel explicit. 
According to the 2nd to last para in the doc, the first 
version is accepted for backward compatibility

I'll look at Ethan's patch next.

>
> 	Ethan