[Help-gsl] Memory allocation problems for large matrices

[Tim Sutton]

Hi There

I am trying to load a largish matrix (7532 x 6286) with values contained in a 
file. I calculate the memory requirements to be around 180mb (is that 
correct?). My laptop on which the application is running has 640mb ram. 
Before starting the app, my free memory is :

             total       used       free     shared    buffers     cached
Mem:           621        254        367          0          6         85
-/+ buffers/cache:        162        459
Swap:          199        131         68

After starting the app, but before attempting to load the matrix, my memory 
is:

             total       used       free     shared    buffers     cached
Mem:           621        259        362          0          6         85
-/+ buffers/cache:        167        454
Swap:          199        131         68

However when my code reaches this line:

currentGslMatrix = gsl_matrix_alloc (myColsInt, myRowsInt);  //7532 , 6286

I get :

gsl: init_source.c:46: ERROR: failed to allocate space for block data
Default GSL error handler invoked.


By my reckoning, there should be enough memory for the array. Can anyone give 
me some pointers on how to trouble shoot this problem. Is there something 
special I need to do to enable me to use larger matrices with gsl? The code 
works fine on the smaller test dataset by the way.

Many thanks in advance for any pearls of wisdom I may receive...

Tim Sutton
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