axis() produces junk on DEC alpha (PR#274)

[ripley@stats.ox.ac.uk]

On Mon, 13 Sep 1999, Martin Maechler wrote:

> >>>>> On Mon, 13 Sep 1999 17:41:07 +0200 (MET DST), ripley@stats.ox.ac.uk (Brian D. Ripley) said:
> 
>     >> Date: Mon, 13 Sep 1999 10:57:23 +0200 (MET DST)
>     >> From: Albrecht Gebhardt <albrecht.gebhardt@uni-klu.ac.at>
>     >>
>     >> On Mon, 13 Sep 1999, Prof Brian D Ripley wrote:
> 
>     BDR> [...]
> 
>     BDR> I'm puzzled.  Are you saying -Inf passes R_FINITE and passes
>     BDR> ISNAN? (Wow!, if so.) In any case, let us try and fix the macros
>     BDR> (which crop up in many places) not two instances.
>     BDR>
>     >> NaN passed R_FINITE (see above). Then it gets multiplied by some
>     >> values and serves as tickmark length.
>     >>
>     >> >
>     >> > There are too many options in Arith.h to guess: can you please tell us
>     >> > what path is being taken (HAVE_FINITE, IEEE_754, FINITE_BROKEN, ...).
> 
>     >> in src/include/Rconfig.h:
>     >> /* Floating Point Arithmetic */
>     >> /* #undef HAVE_MATHERR */               /* System V */
>     >> #define HAVE_ISNAN 1            /* IEEE Arith indicator */
>     >> #define HAVE_FINITE 1
>     >>
>     >> /* #undef HAVE_FLOATINGPOINT_H */
>     >> /* #undef HAVE_FPU_CONTROL_H */
>     >> /* #undef HAVE_IEEEFP_H */              /* "-Wall" */
>     >> /* #undef HAVE_IEEE754_H */             /* Linux */
>     >>
>     >> #ifdef HAVE_ISNAN
>     >> #ifdef HAVE_FINITE
>     >> #define IEEE_754
>     >> #endif
>     >> #endif
>     >>
>     >> and some lines below:
>     >> /* Bug Workarounds */
>     >> /* #undef HAVE_OSF_SPRINTF_BUG */
>     >> #define CALLOC_BROKEN 1
>     >> #define FINITE_BROKEN 1
>     >> #define LOG_BROKEN 1
>     >>
>     >>
>     >> >
>     >> > I believe this can all be tested from interpreted R code. I believe you
>     >> > should get  (is.na(c(2.0, Inf, -Inf, NaN, NA)) etc)
>     >> >            2.0 Inf -Inf NaN NA
>     >> > is.na       F   F    F   T   T
>     >> > is.finite   T   F    F   F   F
>     >> > is.infinite F   T    T   F   F
>     >> > is.nan      F   F    F   T   F
>     >>
>     >>
>     >> > is.na(c(2.0, Inf, -Inf, NaN, NA))
>     >> [1] FALSE FALSE FALSE  TRUE  TRUE
>     >> > is.finite(c(2.0, Inf, -Inf, NaN, NA))
>     >> [1] TRUE TRUE TRUE TRUE TRUE
>     >> > is.infinite(c(2.0, Inf, -Inf, NaN, NA))
>     >> [1] FALSE FALSE FALSE FALSE FALSE
>     >> > is.nan(c(2.0, Inf, -Inf, NaN, NA))
>     >> [1] FALSE FALSE FALSE  TRUE FALSE
>     >>
>     >> Seems that everything is R_FINITE!
> 
>     BDR> [...]
> 
>     BDR> OK, so I think you are at the line
> 
>     BDR> #   define R_FINITE(x)          ((x) != R_NaReal)
> 
>     BDR> in Arith.h, and that is clearly inadequate (although it should have
>     BDR> caught the NA, I think). Can you please try replacing that line by
> 
>     BDR> static int R_FINITE(double x) {
>     BDR> return !isnan(x) & (x != R_PosInf) & (x != R_NegInf);
>     BDR> }
> 
>     BDR> and try those tests again.
> 
>     BDR> (Kurt: looks like finite can be broken in more ways than one. I suggest
>     BDR> return(finite(1./0.) & finite(0./0.) & finite(-1./0.)) in aclocal.m4,
> 
> shouldn't this be "|" instead of "&"   [broken if either is finite] ?

Um. Yes, I think so: the man page is almost impossible to decipher, and
I had read it reversed.

> {weak voice in the background:
>  it may be worth tyring to be both right and efficient ..
>  but I agree that "right" is much more important!

Not, I think, on platforms where the inbuilt ways are broken.

-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595


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