[R] R crashes on quantreg

Prof Brian Ripley ripley at stats.ox.ac.uk
Wed Jun 7 22:15:56 CEST 2006

On Wed, 7 Jun 2006, roger koenker wrote:

> Since the "crash" occurs plotting the lm object it is unclear what
> this has to do with quantreg, but maybe you could explain
> 	1.  what you mean by crash,
> 	2.  something about x,y,
> This is best addressed to the maintainer of the package rather than to
> R-help, provided, of course, that it is really a question about
> quantreg.

Agreed, but just so R-help knows how to solve such problems, I ran this 
under valgrind (see `Writing R Extensions') and got

> rq1 <- rq(y~x)
==7870== Invalid write of size 8
==7870==    at 0x9ED8BDE: rqbr_ (rqbr.f:309)
==7870==  Address 0x92162A0 is 12,248 bytes inside a block of size 12,288 free'd
==7870==    at 0x49055DD: free (vg_replace_malloc.c:235)
==7870==    by 0x53D64A: build_trtable (regex.c:9618)
==7870==    by 0x53AEB4: transit_state (regex.c:8393)
==7870==    by 0x538977: check_matching (regex.c:7318)
==7870==    by 0x537E89: re_search_internal (regex.c:7007)
==7870==    by 0x53EF3D: Rregexec (regex.c:10440)
==7870==    by 0x438AAF: do_gsub (character.c:1127)

and it seems object lm1 has been trashed and you soon get a segfault.

Brian D. Ripley,                  ripley at 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 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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