> 1. Fortran-style complex numbers and failing to distinguish betwee
> +/-0 lead to some numerical problems in physically important contexts.

I tried to find the paper where he discusses this, and I found
numerous references to it but not the paper itself.  Can you
summarize what -0 is needed for?  It seems that -0 would have
to produce a different result from +0 to make a difference,
but I can't think of what function would have those different
results.  He mentions SQRT, and something about branch cuts, but
I don't get it.

He says APL set 0/0 = 1.  Is that just his blunder?

Henry Rich

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