How to increase memory and max array length!?

Hi,

I'm trying to process MRI images in MATLAB, but when I try to execute this line:

   T1_h = h1_aux'*ones(1,2^16);

where h1_aux is (2^16,1) so that the result T1_h should be a [2^16 x 2^16] 'double' matrix, MATLAB runs out of memory:

   ??? Out of memory. Type HELP MEMORY for your options.

since the number of elements in largest real double array is 2^{48}-1 (~2.8e14) for mi 64-bit Windows 7 running 64-bit MATLAB R2010b

And this is what I get when I type the 'memory' command at this point of execution:

   >> memory
   Maximum possible array:              12297 MB (1.289e+010 bytes) *
   Memory available for all arrays:     12297 MB (1.289e+010 bytes) *
   Memory used by MATLAB:                 973 MB (1.020e+009 bytes)
   Physical Memory (RAM):                8173 MB (8.570e+009 bytes)

   *  Limited by System Memory (physical + swap file) available.

Due to the algorithm that I'm implementing, I cannot break this matrix into smaller ones to process them separately.

How can I increase the memory to increase the length of the arrays and avoid this message?

Thank you.

Angel TC.

Answer 1

[Jonathan Sullivan]

Buy more RAM. By my calculation, a 2^16x2^16 matrix of doubles would require 32 GB of RAM. Chances are you'll be making at least 1 more matrix during you computations that is this size. And in some additional RAM for your system to use, and your are talking ~68 GB of RAM.

Answer 2

[Walter Roberson]

The array you are trying to build is 2^35 bytes, which is 32 gigabytes. If you can't go sparse for it, you need to add more physical memory or more swap space.

Answer 3

[Keita Ikeda]

I have the same problem.

I have a vector: 125001408x1 int16 which is about 250 MB

I have 48 GB of physical RAM: >> memory Maximum possible array: 42866 MB (4.495e+10 bytes) * Memory available for all arrays: 42866 MB (4.495e+10 bytes) * Memory used by MATLAB: 1671 MB (1.752e+09 bytes) Physical Memory (RAM): 49143 MB (5.153e+10 bytes)

• Limited by System Memory (physical + swap file) available.

As you can see, I am nowhere close to using my Physical Memory (RAM). If I try to see the vector in Workspace, I get:

Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space

and I can't plot it or even look at it. How may I increase this "Java heap space?"

Thank you in advance, Keita

Answer 4

[Imran Muhammad]

>> memory Maximum possible array: 745 MB (7.809e+08 bytes) *

Memory available for all arrays: 1310 MB (1.374e+09 bytes)

Memory used by MATLAB: 426 MB (4.467e+08 bytes)

Physical Memory (RAM): 2954 MB (3.097e+09 bytes)

• Limited by contiguous virtual address space available.

Limited by virtual address space available. >>

how can i increase maximum possible array memory?