Randy wrote:
>I thought this problem, not bug, was the same as:
>
> datatype 1.2 - 0.2
>float
>
>but I couldn't see how.
Well, it can be construed that way. If you don't need floats (i.e. your domain
is restricted to ints or bools), then the default sparse element, which is a
floating point zero, is a tad wasteful.
If you're sure that you don't need floats and your intermediate results will
never force promotion to float, then you can specify a different sparse
element. Use int 0 or bool 0 as required by your specific application.
Regarding how to specify those values, the short answer is:
bool_0 =: 0
int_0 =: {. 0 2
For more specifics, see:
http://www.jsoftware.com/jwiki/Guides/Constants#head-dd5d17611fae0ca16e2f401e2def8cd989493567
and the thread:
http://www.jsoftware.com/pipermail/programming/2007-February/005048.html
> reading every byte of the help, something I gave up doing in '95.
I agree this method is not helpful in advance of your need, but if you have a
specific question about a primitive, the Vocabulary page for it covers the
ground (though often cryptically). In this case, the various possible x in
x&$. are laid out nicely in a comprehensive table.
Besides, one of Roger's goals is to minimize the number of bytes in the help :)
Other worthwhile resources are the J Forum archives, searchable here:
http://www.jsoftware.com/forumsearch
and now the J wiki, searchable here:
http://www.jsoftware.com/jwiki/FindPage
You can also use Find-in-Files to search through your local copy of the help.
Start the J Session Manager, launch Edit>Find in Files... (or press Control+F),
and fill in the form. Turn off "match case", select "HTML" and "Help"
respectively from the "File Type" and "In folders" dropdowns.
-Dan
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