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Ben Bolker

2026-Jan-26 17:45 UTC

[Rd] R build BLAS/LAPACK debugging ('dgemmtr_' undefined)

I'm sure I'm doing something dumb, but having trouble building R from
source on PopOS! 22.04 LTS (debian/Ubuntu 'jammy' derivative):
"undefined symbol: dgemmtr_" when trying to load stuff from LAPACK.

R appears to find stuff at the configure step (FWIW I get the same error
below if I take out "with-blas=-lopenblas")

$ ../r-devel/configure --enable-R-shlib --enable-memory-profiling
--with-blas=-lopenblas | grep blas
configure: WARNING: C23 support is unavailable
checking for dgemm_ in -lopenblas... yes
config.status: creating src/extra/blas/Makefile

Then `make` fails with:

byte-compiling package 'grDevices'
Warning in solve.default(rgb) :
unable to load shared object
'/home/bolker/R/r-build/modules//lapack.so':
/home/bolker/R/r-build/lib/libRlapack.so: undefined symbol: dgemmtr_
Error in solve.default(rgb) : LAPACK routines cannot be loaded

I do see a NEWS item from R 4.5.0
https://github.com/r-devel/r-svn/blob/42e81d981a540f4afc01d1002a64ab347eb5dc15/doc/NEWS.Rd#L956-L961
(I thought things were working until recently, but I haven't re-built
from scratch in a while ...)

\item This update was mainly bug fixes but contained a barely
documented major change. The set of BLAS routines had been
unchanged since 1988, so throughout \R's history. This update
introduced new BLAS routines \code{dgemmtr} and \code{zgemmtr}
which are now used by LAPACK routines. This means that BLAS
implementations are no longer interchangeable.

Section A.3.1
https://rstudio.github.io/r-manuals/r-admin/Essential-and-useful-other-programs-under-a-Unix-alike.html:

> The configure code checks that the external BLAS is complete (as of
LAPACK 3.9.1: it must include all double precision and double complex
routines, as well as LSAME), and appears to be usable. However, an
external BLAS has to be usable from a shared object (so must contain
position-independent code), and that is not checked.

I'd be surprised if by BLAS libraries *didn't* contain PIC, but ...
??

Suggestions for diagnostics/debugging welcome ...

cheers
Ben Bolker

Avraham Adler

2026-Jan-26 18:03 UTC

head link

[Rd] R build BLAS/LAPACK debugging ('dgemmtr_' undefined)

Possibly related, ever since that change to R, I found I have to build
OpenBLAS *with* Lapack because of the change in where OpenBLAS
"stores" some functions. See issue 4684 in the OpenBLAS Github repo
[1]. As a result, you will see a much larger .a file. However, the
processor-named and unnamed (just libopenblas.a) should now be the
same after 4692 [2]. Either one works, at least for me,

Hope that helps,

Avi

[1] https://github.com/OpenMathLib/OpenBLAS/issues/4684
[2] https://github.com/OpenMathLib/OpenBLAS/discussions/4692

On Mon, Jan 26, 2026 at 12:45?PM Ben Bolker <bbolker at gmail.com>
wrote:>
>
>    I'm sure I'm doing something dumb, but having trouble building R
from
> source on PopOS! 22.04 LTS (debian/Ubuntu 'jammy' derivative):
> "undefined symbol: dgemmtr_" when trying to load stuff from
LAPACK.
>
> R appears to find stuff at the configure step (FWIW I get the same error
> below if I take out "with-blas=-lopenblas")
>
> $ ../r-devel/configure --enable-R-shlib --enable-memory-profiling
> --with-blas=-lopenblas | grep blas
> configure: WARNING: C23 support is unavailable
> checking for dgemm_ in -lopenblas... yes
> config.status: creating src/extra/blas/Makefile
>
> Then `make` fails with:
>
> byte-compiling package 'grDevices'
> Warning in solve.default(rgb) :
>    unable to load shared object
'/home/bolker/R/r-build/modules//lapack.so':
>    /home/bolker/R/r-build/lib/libRlapack.so: undefined symbol: dgemmtr_
> Error in solve.default(rgb) : LAPACK routines cannot be loaded
>
>    I do see a NEWS item from R 4.5.0
>
https://github.com/r-devel/r-svn/blob/42e81d981a540f4afc01d1002a64ab347eb5dc15/doc/NEWS.Rd#L956-L961
> (I thought things were working until recently, but I haven't re-built
> from scratch in a while ...)
>
> \item This update was mainly bug fixes but contained a barely
>        documented major change.  The set of BLAS routines had been
>        unchanged since 1988, so throughout \R's history.  This update
>        introduced new BLAS routines \code{dgemmtr} and \code{zgemmtr}
>        which are now used by LAPACK routines.  This means that BLAS
>        implementations are no longer interchangeable.
>
> Section A.3.1
>
https://rstudio.github.io/r-manuals/r-admin/Essential-and-useful-other-programs-under-a-Unix-alike.html:
>
>  > The configure code checks that the external BLAS is complete (as of
> LAPACK 3.9.1: it must include all double precision and double complex
> routines, as well as LSAME), and appears to be usable. However, an
> external BLAS has to be usable from a shared object (so must contain
> position-independent code), and that is not checked.
>
>    I'd be surprised if by BLAS libraries *didn't* contain PIC, but
... ??
>
>    Suggestions for diagnostics/debugging welcome ...
>
>    cheers
>     Ben Bolker
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel

Dirk Eddelbuettel

2026-Jan-26 18:22 UTC

head link

[Rd] R build BLAS/LAPACK debugging ('dgemmtr_' undefined)

On 26 January 2026 at 12:45, Ben Bolker wrote:
| 
|    I'm sure I'm doing something dumb, but having trouble building R
from
| source on PopOS! 22.04 LTS (debian/Ubuntu 'jammy' derivative): 
| "undefined symbol: dgemmtr_" when trying to load stuff from LAPACK.
| 
| R appears to find stuff at the configure step (FWIW I get the same error 
| below if I take out "with-blas=-lopenblas")
| 
| $ ../r-devel/configure --enable-R-shlib --enable-memory-profiling 
| --with-blas=-lopenblas | grep blas
| configure: WARNING: C23 support is unavailable
| checking for dgemm_ in -lopenblas... yes
| config.status: creating src/extra/blas/Makefile

FWIW in all my build script(s) (for local r-devel builds, or the Debian R
package, or container builds from source) I explicitly set the --with-blas
and the --with-lapack flags.  As dgemm() is (well known) LAPACK routine [1] I
think you are "simply" forgetting to link with LAPACK here.

Cheers, Dirk

[1]
https://www.netlib.org/lapack/explore-html/dd/d09/group__gemm_ga1e899f8453bcbfde78e91a86a2dab984.html

| 
| Then `make` fails with:
| 
| byte-compiling package 'grDevices'
| Warning in solve.default(rgb) :
|    unable to load shared object
'/home/bolker/R/r-build/modules//lapack.so':
|    /home/bolker/R/r-build/lib/libRlapack.so: undefined symbol: dgemmtr_
| Error in solve.default(rgb) : LAPACK routines cannot be loaded
| 
|    I do see a NEWS item from R 4.5.0 
|
https://github.com/r-devel/r-svn/blob/42e81d981a540f4afc01d1002a64ab347eb5dc15/doc/NEWS.Rd#L956-L961
| (I thought things were working until recently, but I haven't re-built 
| from scratch in a while ...)
| 
| \item This update was mainly bug fixes but contained a barely
|        documented major change.  The set of BLAS routines had been
|        unchanged since 1988, so throughout \R's history.  This update
|        introduced new BLAS routines \code{dgemmtr} and \code{zgemmtr}
|        which are now used by LAPACK routines.  This means that BLAS
|        implementations are no longer interchangeable.
| 
| Section A.3.1 
|
https://rstudio.github.io/r-manuals/r-admin/Essential-and-useful-other-programs-under-a-Unix-alike.html:
| 
|  > The configure code checks that the external BLAS is complete (as of 
| LAPACK 3.9.1: it must include all double precision and double complex 
| routines, as well as LSAME), and appears to be usable. However, an 
| external BLAS has to be usable from a shared object (so must contain 
| position-independent code), and that is not checked.
| 
|    I'd be surprised if by BLAS libraries *didn't* contain PIC, but ...
??
| 
|    Suggestions for diagnostics/debugging welcome ...
| 
|    cheers
|     Ben Bolker
| 
| ______________________________________________
| R-devel at r-project.org mailing list
| https://stat.ethz.ch/mailman/listinfo/r-devel

-- 
dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org

Ivan Krylov

2026-Jan-26 19:28 UTC

head link

[Rd] R build BLAS/LAPACK debugging ('dgemmtr_' undefined)

? Mon, 26 Jan 2026 12:45:41 -0500
Ben Bolker <bbolker at gmail.com> ?????:
> Then `make` fails with:
> 
> byte-compiling package 'grDevices'
> Warning in solve.default(rgb) :
>    unable to load shared object
> '/home/bolker/R/r-build/modules//lapack.so':
> /home/bolker/R/r-build/lib/libRlapack.so: undefined symbol: dgemmtr_
> Error in solve.default(rgb) : LAPACK routines cannot be loaded
.../configure --with-2025blas should help with this by linking the
subroutines missing in older versions of OpenBLAS but required by
R-bundled LAPACK from a separate file.

-- 
Best regards,
Ivan

R devel - Jan 2026 - R build BLAS/LAPACK debugging ('dgemmtr_' undefined)

[Rd] R build BLAS/LAPACK debugging ('dgemmtr_' undefined)

[Rd] R build BLAS/LAPACK debugging ('dgemmtr_' undefined)

[Rd] R build BLAS/LAPACK debugging ('dgemmtr_' undefined)

[Rd] R build BLAS/LAPACK debugging ('dgemmtr_' undefined)