gnhlug-discuss-boun...@mail.gnhlug.org wrote on 05/10/2010 10:21:50 AM:
> Fellow list members, I've got a linux linking problem, which has me
> stumped. Since I've been coding mostly in python, lately, my 'C' brain
> has atrophied...
>
> I've got a C (umm actually C++) program that won't link to some ATLAS
> libraries which I recently compiled. The program itself will compile,
> link and run if I link to the baseline (non-optimized) ATLAS libraries.
I
> think it even gives the expected result, as an added bonus!
>
> However, if I use "/usr/local/atlas/include/cblas.h" instead of the
system
> "/usr/include/cblas.h" in the code snippet below,
>
> extern "C"{
> #include "/usr/local/atlas/include/cblas.h"
> }
>
> the build reports:
> $ ./build_cblas_test
> Building cblas1
> /tmp/ccSMmtzW.o: In function `main':
> cbas_tb.cpp:(.text+0x899): undefined reference to `cblas_zgemm'
> collect2: ld returned 1 exit status
> Build complete
>
> My build file --> not a make file yet because it is just a one liner,
is:
>
> g++ -O3 -m64 -I/usr/local/atlas/include -L/usr/local/atlas/lib -lcblas
-lm
> -Wall -Wcast-qual -o cblas1 cblas_tb.cpp
>
> I've tried copying the include file and lib file and stuffing them in
the
> same directory as the cpp file, but to no avail. (Yes I modified the
> command above.)
>
> Before anyone asks, yes, there are files at the locations. The new
> cblas.h file looks very close to the old, although I have not run a diff
> on them. ( cblas_zgemm is in the new header, I looked.) The library is
> static. Is there a tool to look inside an .a file?
>
> I figure the problem is probably an operator error, sigh, but I'm not
sure
> what it is. If someone could point me in the right direction, I'd
> appreciate it. Assume nothing - it is probably basic. :(
>
> I can post the code if people think it would help. (Just didn't want to
> make this email any longer than necessary.)
>
For the sake of completeness: here is the source:
// ==== start of source file ====
/*
** cblas_tb.cpp -- an initial stab at implementing a matrix matrix
multiply
using the blas library. This is a precursor file for LAPACK
Origin Date: 5 May 2010
*/
#include <stdio.h>
#include <complex>
extern "C"{
#include "/usr/local/atlas/include/cblas.h"
}
using namespace std;
using std::complex;
typedef complex<double> dcomp; /* Define complex double data type */
int main(void)
{
int i, j, M, N;
M = 5; N = 5;
dcomp A[M][N];
// init A to eye(5), sort of...
printf("Initial value of A\n");
for(i=0; i<M; i++)
{
for (j=0; j<N; j++)
{
if (i==j)
{
A[i][j] = dcomp(1.0, 0.1);
}
else
{
A[i][j] = dcomp(0.0, 0.0);
}
printf("A[%i][%i]= %f, %f\n", i, j, real(A[i][j]),
imag(A[i][j]));
}
}
printf("\n");
dcomp C[M][N];
double NN = 1.0/double(N);
dcomp alpha = dcomp(NN, 0.0);
dcomp beta = dcomp(0.0, 0.0);
int m,k,n; // matrix dimensions, A = [m x k], B = [k x n]
m = 5; k = 5; n =5;
int ldA, ldB, ldC;
ldA = 5; ldB = 5; ldC = 5;
cblas_zgemm(CblasRowMajor, CblasNoTrans, CblasConjTrans, m, n, k,
&alpha,
A, ldA, A, ldB, &beta, C, ldC);
printf("Computed value for C\n");
for (i=0; i<5; i++)
{
for (j=0; j<5; j++)
{
printf("C[%i][%i]= %f, %f\n", i, j, real(C[i][j]),
imag(C[i][j]));
}
}
return 0;
}
// ==== end of source file ================
Adding a -v to the compile reveals:
$ ./buildcblas_test
Building cblas1
Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
4.4.3-4ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr
--enable-shared --enable-multiarch --enable-linker-build-id
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --with-gxx-include-dir=/usr/include/c++/4.4
--program-suffix=-4.4 --enable-nls --enable-clocale=gnu
--enable-libstdcxx-debug --enable-plugin --enable-objc-gc --disable-werror
--with-arch-32=i486 --with-tune=generic --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
COLLECT_GCC_OPTIONS='-O3' '-m64' '-v' '-I/usr/local/atlas/include'
'-L/usr/local/atlas/lib/' '-Wall' '-Wcast-qual' '-o' 'cblas1'
'-shared-libgcc' '-mtune=generic'
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/cc1plus -quiet -v
-I/usr/local/atlas/include -D_GNU_SOURCE cblas_tb.cpp -D_FORTIFY_SOURCE=2
-quiet -dumpbase cblas_tb.cpp -m64 -mtune=generic -auxbase cblas_tb -O3
-Wall -Wcast-qual -version -fstack-protector -o /tmp/ccMNCUj8.s
GNU C++ (Ubuntu 4.4.3-4ubuntu5) version 4.4.3 (x86_64-linux-gnu)
compiled by GNU C version 4.4.3, GMP version 4.3.2, MPFR version
2.4.2-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/4.4.3/../../../../x86_64-linux-gnu/include"
ignoring nonexistent directory "/usr/include/x86_64-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/atlas/include
/usr/include/c++/4.4
/usr/include/c++/4.4/x86_64-linux-gnu
/usr/include/c++/4.4/backward
/usr/local/include
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/include
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/include-fixed
/usr/include
End of search list.
GNU C++ (Ubuntu 4.4.3-4ubuntu5) version 4.4.3 (x86_64-linux-gnu)
compiled by GNU C version 4.4.3, GMP version 4.3.2, MPFR version
2.4.2-p1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 88858f45841827736473e527a4e9ab10
COLLECT_GCC_OPTIONS='-O3' '-m64' '-v' '-I/usr/local/atlas/include'
'-L/usr/local/atlas/lib/' '-Wall' '-Wcast-qual' '-o' 'cblas1'
'-shared-libgcc' '-mtune=generic'
as -V -Qy --64 -o /tmp/cciYxVSy.o /tmp/ccMNCUj8.s
GNU assembler version 2.20.1 (x86_64-linux-gnu) using BFD version (GNU
Binutils for Ubuntu) 2.20.1-system.20100303
COMPILER_PATH=/usr/lib/gcc/x86_64-linux-gnu/4.4.3/:/usr/lib/gcc/x86_64-linux-gnu/4.4.3/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/4.4.3/:/usr/lib/gcc/x86_64-linux-gnu/:/usr/lib/gcc/x86_64-linux-gnu/4.4.3/:/usr/lib/gcc/x86_64-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/x86_64-linux-gnu/4.4.3/:/usr/lib/gcc/x86_64-linux-gnu/4.4.3/:/usr/lib/gcc/x86_64-linux-gnu/4.4.3/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-linux-gnu/4.4.3/../../../:/lib/:/usr/lib/:/usr/lib/x86_64-linux-gnu/
COLLECT_GCC_OPTIONS='-O3' '-m64' '-v' '-I/usr/local/atlas/include'
'-L/usr/local/atlas/lib/' '-Wall' '-Wcast-qual' '-o' 'cblas1'
'-shared-libgcc' '-mtune=generic'
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/collect2 --build-id --eh-frame-hdr -m
elf_x86_64 --hash-style=both -dynamic-linker /lib64/ld-linux-x86-64.so.2
-o cblas1 -z relro
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/../../../../lib/crt1.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/../../../../lib/crti.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/crtbegin.o -L/usr/local/atlas/lib/
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.3
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.3
-L/usr/lib/gcc/x86_64-linux-gnu/4.4.3/../../../../lib -L/lib/../lib
-L/usr/lib/../lib -L/usr/lib/gcc/x86_64-linux-gnu/4.4.3/../../..
-L/usr/lib/x86_64-linux-gnu -lcblas /tmp/cciYxVSy.o -lstdc++ -lm -lgcc_s
-lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/x86_64-linux-gnu/4.4.3/crtend.o
/usr/lib/gcc/x86_64-linux-gnu/4.4.3/../../../../lib/crtn.o
/tmp/cciYxVSy.o: In function `main':
cblas_tb.cpp:(.text+0x899): undefined reference to `cblas_zgemm'
collect2: ld returned 1 exit status
Build Complete
If I look inside of /usr/local/atlas/lib/libcblas.a using elfreader (
thanks Michael! ) I get:
$ readelf -a libcblas.a | grep cblas_zgemm
File: libcblas.a(cblas_zgemm.o)
1: 0000000000000000 0 FILE LOCAL DEFAULT ABS cblas_zgemm.c
24: 0000000000000000 1533 FUNC GLOBAL DEFAULT 1 cblas_zgemm
There is something there. Somewhat reasonable stuff inside of
libcblas.a...
Any ideas?
TIA
-Bruce
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