Thanks for your prompt response. The LD_DEBUG thing is a handy trick!
The ld debug output shows libpgmp.so and libpgc.so load successfully from the right place (same directory as the PGI libacml_mp.so). There are no errors or warnings in the output.
It seems unlikely that I’ll be able to get to the bottom of this without a sizable time commitment, so I’ll have to settle for a single-threaded ACML.
My impression is that, in spite of the answer Chris got from the Matlab folks, there should be a way to get a multithreaded ACML working with Matlab. Intel’s MKL does this sucessfully, and I don’t see any reason Matlab should know or care whether there are multiple threads under the hood when it makes a LAPACK/BLAS call.
Has PGI considered deliberately targetting Matlab users with their ACML? I don’t know what PGI’s consumer demograhics are like, but multi-core amd64 systems and Matlab go really well together – or would, if there were a multithreaded amd64 ACML implementation Matlab could handle. If PGI could work out the kinks with Matlab, they would have a (rapidly growing) captive audience.