MEMORY_TEST, a MATLAB program which declares and uses a sequence of larger and larger arrays, to see what the memory limits are on a given computer.
The program tries an increasing series of values of N, using powers of 2, between limits that you set. At some point, the program may ask for more memory than can be provided, and crash. This is one way to find out what the memory ceiling is! The relevant power of 2 is likely to be in the 20's:
| Log(N) | N |
|---|---|
| 20 | 1,048,576 |
| 21 | 2,097,152 |
| 22 | 4,194,304 |
| 23 | 8,388,608 |
| 24 | 16,777,216 |
| 25 | 33,554,432 |
| 26 | 67,108,864 |
| 27 | 134,217,728 |
| 28 | 268,435,456 |
| 29 | 536,870,912 |
| 30 | 1,073,741,824 |
Remember that your memory is probably described in terms of bytes, but that integers and reals require 4 bytes, and double precision reals require 8 bytes.
memory_test ( log_n_min, log_n_max )runs the program for sizes N = 2log_n_min to 2log_n_max.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
MEMORY_TEST is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.
LINPACK_BENCH, a MATLAB program which measures the time needed to factor and solve a linear system.
MACHINE, a MATLAB library which can return various machine constants.
TIMER, a MATLAB program which demonstrates how to compute CPU time or elapsed time.