out memory problem

2011 10 10
2 个回答
3 次查看（30 天）

0 个投票

hi, My array of data is 211,231*4,when process it I got this error:
Out of memory. Type HELP MEMORY for your options. keep in mind, I use clear ,close matlab and open it what I have to do to get over this error.
Thanks in advance

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回答（2 个）

Jan
Jan 2011-10-10

0 个投票

Do you mean a [211'231 x 4] array? This array has 6.7 MB only, such that the must be another large array, which occupies much more memory.
Please post the corresponding source code, which is used to the create the array.

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huda nawaf
huda nawaf 2011-10-10
thanks:
I read from file , then print it to array
the file with size 4.61 MB. the problem that the running time one hour. I don't know where is the problem
this is code:
f=fopen('ws.data','r+');%%%%%% open the original data file
b1=fscanf(f,'%d');
b=sprintf('%d\n', b1);
fclose all
L=length(b);
k=1;i=1
while k<=L
for j=1:4
mat(i,j)=b(k);
k=k+1;
end
i=i+1;
end
for k2=1:i-1
k1=1;
for j=1:2:4
mat1(k2,k1)=mat(k2,j);
k1=k+1;
end
end
Jan
Jan 2011-10-10
What do you want to achieve? Please search in this forum and the net for the term "pre-allocation".
Walter Roberson
Walter Roberson 2011-10-10
Please take some time, Huda, to read about "vectorization" in MATLAB. You have been using MATLAB for some time now; it is time for you to study that topic and put it in to practice.
And, like Jan says, pre-allocate.

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Walter Roberson
Walter Roberson 2011-10-10

0 个投票

Is that 211231 x 4, each entry a double precision number (8 bytes), or is it 211 x 231 with each entry a 4 byte number, or is it 211 x 231 x 4, each entry a double precision number (8 bytes)?
If it is 211231 x 4 double-precision entries, that should be only 6.4 megabytes; if you are unable to allocate a 6.4 megabyte array then you are too short on memory to do anything practical.
Please show the exact call you use to allocate the memory.
For example, if you were using
A = zeros(211231*4)
then we would immediately diagnose the problem as being that when you supply only a single scalar size to zeros() (or ones(), or rand()) then a square matrix is constructed that is that number of rows and columns.

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huda nawaf
huda nawaf 2011-10-10
thanks:
I read from file , then print it to array(no. of rows are 211231, and columns are 4)
the file with size 4.61 MB. the problem that the running time one hour. I don't know where is the problem
huda nawaf
huda nawaf 2011-10-12
Thanks,I will check pre-allocate. As you asked me, I ran A(1:211231,1:4)=1
,there is no problem,it is not take time to run.
please help me , below the code again:
f=fopen('ws.txt','r+');%%%%%% open the original data file
b=fscanf(f,'%d');
fclose (f)
L=length(b);
k=1;i=1
while k <=L
for j=1:4
mat(i,j)=b(k);
k=k+1;
end
i=i+1;
end
Walter Roberson
Walter Roberson 2011-10-12
This is pretty much the same problem I solved for you over in http://www.mathworks.com/matlabcentral/answers/17949-problem-in-sprintf
the whole code after the fclose() can be replaced with a reshape().
huda nawaf
huda nawaf 2011-11-28
I change my computer, now my computer has RAM with 4 Gb instead of the old that has 1.8 Gb , unfortunately , the same problem
with this code:
the structure of files as
ex.
(1,1) 1000
(2,1) 12
.
.
.
fid = fopen('d:\matlab\R2011a\bin\flixsterdata\finalflix0.txt','r');
c = textscan(fid, '(%d,%d)\t%d');
c1=double(c{1});c2=double(c{2});c3=double(c{3});
L=length(c1)%%%L= 2444547
w=double(c1(1:L)); w1=double(c2(1:L)); w2=double(c3(1:L));
flix0=accumarray([w,w1],w2);
please, help me what I have to do?
Walter Roberson
Walter Roberson 2011-11-28
It might help to stop making so many copies of variables.
fid = fopen('d:\matlab\R2011a\bin\flixsterdata\finalflix0.txt','r');
c = textscan(fid, '(%g,%g)\t%g');
fclose(fid);
flix0 = accumarray([c{1}, c{2}], c{3}]);
By the way, what is max(c{1}) and max(c{2}) ?
huda nawaf
huda nawaf 2011-11-29
thanks,
max(c1)=50000
max(c2)=30977
length(c1)=2444547
Walter Roberson
Walter Roberson 2011-11-29
Urrr, you will definitely want to use a cell array or sparse matrix for that -- accumarray would need about 12 Gb to store that matrix in non-sparse form.
huda nawaf
huda nawaf 2011-11-29
I did what you suggested regarding variables
the problem is still.
what about dynamic array?
can solve my problem?
Walter Roberson
Walter Roberson 2011-11-29
I never looked up the storage requirements for sparse arrays.
What do you mean by "dynamic array" in this context?
huda nawaf
huda nawaf 2011-11-30
someone who is working with aother language suggest to work with dyn. array, I'm not familiar with it,ut i will read about it if it is in matlab
walter, please tell me how I can use cell array to solve my prolem
give me example please.
thanks
Walter Roberson
Walter Roberson 2011-11-30
I never did find out what problem it is you are really trying to deal with -- though I did ask a few times.

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huda nawaf
huda nawaf
2011-10-10

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