RE: [bgl-discuss] FFTW configure error

[William Gropp <gropp@xxxxxxxxxxx>]

At 11:29 AM 8/26/2005, Andrew Siegel wrote:
> Many thanks. Were you able to subsequently link? Turns out that no one here
> has actually used the library yet and it would save us a little time if
> someone who has already done it had the dependency list. Thanks! -andrew

Link errors of the form

> In function `fftwi_twiddle_rader':
> rader.o(.text+0x158): undefined reference to `__divi64'
> rader.o(.text+0x2d4): undefined reference to `__divi64'

usually result from compiling with one compiler and linking with a 
different one, where the compiler calls its own, private routines for 
handling cases that aren't handled by the hardware.  These often have a two 
underscore prefix and names like divi64 (64 bit integer division, 
perhaps?).  E.g., compiling the library with gcc and linking with xlc or 
vice versa may cause this (we've seen this with MPICH and MPICH2 on similar 
platforms).  The fix is to either link with the same compiler or (more 
risky) add the runtime libraries used by the "other" compiler.

Bill

William Gropp
http://www.mcs.anl.gov/~gropp 

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