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...ncoder_set_current_frame_number(). I also zero out the min/max frame size fields in the metadata, which should be the only byte difference between the files the multithreaded encoder outputs and the ones the example libFLAC one outputs (well, and md5). Patch file for flac 1.2.1 or CVS: http://www.akalin.cx/patch-libFLAC.in Source file for multithreaded FLAC encoder: http://www.akalin.cx/mt_encode.c mt_encode.c should compile on gcc 4.x with -Wall -Werror -g -O2 -ansi . Usage is simply "mt_encode.c input.wav output.flac [num_threads]". Of course, I'm not suggesting that the patch fi...

Along the same line as Frederick, myself and another university student were able to implement a multi threaded FLAC encoder, but using Intel's Threading Building Blocks (TBB) package. We saw similar near-linear speedup. Our solution is a bit more convoluted since we were learning the API, TBB and writing the encoder all in one 6 week period. We used a pipeline model on the input stream, and

...I wrote it so that it can easily be replaced by non-blocking constructs (which is beyond the scope of this version) -- an earlier version used non-blocking constructs but moving to pthread locks didn't seem to affect performance so the bottleneck isn't there. Updated patch file: http://www.akalin.cx/patch-libFLAC.2.in Source file for this version: http://www.akalin.cx/mt_encode2.c This should also compile cleanly with gcc 4.x with -Wall -Werror -g -O2 -ansi. Comments and thoughts on this version are welcome. -- Frederick Akalin http://www.akalin.cx

...ile- or block-based > API. It would be more effort to maintain, but there is a gain for the added > work, now that multiple processors is more common, even on laptops. The > flac-mt command-line also seems like a good idea. Cool! I'll start working on something then. -- Frederick Akalin http://www.akalin.cx

...encoding API was obviously designed for serial execution, and any internal > threading support would be messy. We had to come up with quite a few tricks to modify as little of libFLAC as possible. It looks like implementing parallel-friendly APIs is indeed the logical next step. -- Frederick Akalin http://www.akalin.cx

On May 6, 2008, at 14:20, Frederick Akalin wrote: > On Tue, May 6, 2008 at 2:03 PM, Brian Willoughby > <brianw at sounds.wa.com> wrote: >> 3) Do you accelerate decode as well as encode? I'm thinking that >> the >> variable block size would require each thread to scan its block >> for the >&...

...file- or block- based API. It would be more effort to maintain, but there is a gain for the added work, now that multiple processors is more common, even on laptops. The flac-mt command-line also seems like a good idea. Brian Willoughby Sound Consulting On May 6, 2008, at 11:31, Frederick Akalin wrote: > I managed to hack out a proof-of-concept multithreaded FLAC encoder > based on the example libFLAC one. It turned out to be fairly > straightforward to get near-linear speedup; I can encode a 636 MB wave > file in 6.8s with 8 threads on an 8-core 3.0 GHz Xeon vs. 31.4s with a...

Hi All, I'm trying to run generalized singular value decomposition (GSVD) function from LAPACK library. Basically my problem is that I can not run it for large matrices, I get a memory error. I'm using R 2.5.1. I tried this on intel centos5 machines with 2 GB memory and 8 GB memory. I have unlimited max memory,cpu time and virtual memory. LAPACK is already compiled for R