Hi Mark,
> (* symbol lookup error: /usr/lib/x86_64-linux-gnu/libgsl.so: undefined
> symbol: cblas_dgemm *)
To avoid looking for the symbol "cblas_dgemm" in libgsl (which doesn't
define it), you could let the dynamic linker look for it by using an
empty string for the library which has the effect of passing
RTLD_DEFAULT to dlsym.
val gsl = loadLibrary "";
To make sure these libraries are searched, you would need to start your
poly session with something like
LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libgsl.so":"/usr/lib/x86_64-linux-gnu/libgslcblas.so
\
poly
which could be put into a wrapper script. Or you could build an
executable (which could be a poly REPL) and link to them.
Another advantage of this approach is portability. The SML code is more
portable because shared object names and their paths vary across
systems. Linking also avoids the problem of specifying the library
names because you use flags such as -lgsl and the linker works it out.
Linking can be done in an even more portable way using a utility like
pkg-config to generate the linker arguments:
pkg-config --libs gsl
(This usual requires the -devel or -dev package for the library.)
Regards,
Phil
On 09/09/18 21:15, Mark Clements wrote:
I am enjoying using polyml's Foreign structure.
However, in using the GNU Scientific Library (GSL), I have run into a
problem with linkage. The GSL library (libgsl.so) calls standard cBLAS
matrix functions with unknown symbols to allow the user to link with
different cBLAS implementations (NB: GSL provides an unoptimised cBLAS
implementation named libgslcblas.so). When I call a GSL function that
depends on the cBLAS functions, I get a symbol not defined error.
I have tried unsuccessfully (a) loading the libgslcblas library either
before or after loading libgsl, (b) changing the loadLibrary
implementation to use dlopen with RTLD_LAZY | RTLD_GLOBAL, and (c)
compiling the SML code to an object file and then linking against the
libraries.
How could this be made to work?
Sincerely, Mark.
PS test code for (a) is:
open Foreign;
val gsl = loadLibrary "/usr/lib/x86_64-linux-gnu/libgsl.so";
val gslcblas = loadLibrary "/usr/lib/x86_64-linux-gnu/libgslcblas.so";
type gsl_matrix_t = Memory.voidStar; (* for demonstration only *)
local
val call1 = buildCall2((getSymbol gsl "gsl_matrix_calloc"),
(cInt,cInt), cPointer)
val call2 = buildCall4((getSymbol gsl "gsl_matrix_set"),
(cPointer,cInt,cInt,cDouble), cVoid)
val call3 = buildCall3((getSymbol gsl
"gsl_linalg_exponential_ss"), (cPointer, cPointer, cDouble), cVoid)
in
fun gsl_matrix_alloc (size1,size2) = call1(size1,size2)
fun gsl_matrix_set (ptr : gsl_matrix_t, i, j, x) = call2(ptr, i, j, x)
fun gsl_matrix (arr : real Array2.array) =
let
val size1 = Array2.nRows arr
val size2 = Array2.nCols arr
val ptr = gsl_matrix_alloc(size1, size2)
val _ = Array2.tabulate Array2.RowMajor (size1, size2, fn (i,j) =>
gsl_matrix_set(ptr, i, j, Array2.sub(arr, i, j)))
in
ptr
end
fun gsl_mexp (arr : real Array2.array) =
let
val size1 = Array2.nRows arr
val size2 = Array2.nCols arr
val ptr = gsl_matrix arr
val ptr2 = gsl_matrix_alloc(size1, size2)
val _ = call3(ptr, ptr2, 0.01)
in
ptr2
end
end;
fun main() =
let
val a = Array2.fromList [[1.0,2.0],[3.0,4.0]];
val ptr = gsl_matrix(a);
val m = gsl_mexp(a) (* fails *)
in
()
end;
(* symbol lookup error: /usr/lib/x86_64-linux-gnu/libgsl.so: undefined
symbol: cblas_dgemm *)
For (c):
polyc -c test.sml
g++ test.o -L/usr/lib/x86_64-linux-gnu -lgsl -lgslcblas `pkg-config
--libs polyml`
./a.out
# same error
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