I am running what I know is a large problem for a scientific application (tochnog) a finite element solver that I help develop and maintain. The application runs out of the OSX Terminal application. Recently, I implemented the use of the LAPACK library built into the Accelerate framework in OSX as the main solver. The other option being a biconjugate solver.
When I use the application tries to solve 1,320,000 simultaneous linear equations, the problem starts when I use the Accelerate Framework (Which Contains LAPACK) as the Virtual Memory size allocated by OSX jumps from 142 G to about 576 G after the library (LAPACK) is called to solve the system.The same behavior does not happens if I use the biconjugate solver that does not calls LAPACK.
The machine is a mac pro desktop with 8 GB of ram, the 2.66 GHz Quad-core Intel and the standard 640 GB hard drive. The system tells me that I have 487 GB available on hard drive.
After a short while, I get the "No enought room on startup disk for Application Memory" error.
This is a screen capture of the application attempting to solve the problem using the LAPACK library inside the Accelerate framework: Here are the numbers as reported by the activity Monitor.
Tochnog Real Memory 6.68 GB
System Memory Free: 33.8 MB, Wired 378.8 MB, Active 5.06 GB, Inactive 2.53 GB, Used 7.96 GB.
VM size 567.52 GB, Page ins 270.8 MB, Page outs 108.2 MB, Swap used 505 MB
This is a screen copy of the same application solving the same problem without using the Accelerate framework.
Tochnog Real Memory 1.96 GB,
System Memory Free: 4.52 MB, Wired 382.1 MB, Active 2.69 GB, Inactive 416.2 GB, Used 3.47 GB.
VM size 148.60 GB, Page ins 288.8 MB, Page outs 108.2 MB, Swap used 2.5 MB
I can not understand the disparity in the behavior for the same case. As I said before, the only difference is the use of Accelerate in the first case. Also, as you can see, I thought that 8 GB of ram memory was a lot.
What will be the amount of memory required by LAPACK to solve such a problem, for a 64-bit system like OSX?
Do you think that this may be an issue with LAPACK or OSX?
Your help will be greatly appreciated