how to solve a problem associated with memory speed of computer ?

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mohammad 2014-7-30

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https://ww2.mathworks.cn/matlabcentral/answers/143816-how-to-solve-a-problem-associated-with-memory-speed-of-computer

评论： mohammad 2014-7-31

first of all , i have a specific task that works at the expense of every possible combination of range , i already used a program that perform my purpose this code is :

clc
clear
a = input('Please, select your array: ')
b = a(:).'
c = length(b)
for d =1:c
  if (d<c)
    e{d} = nchoosek(b, d);
  end
end
tt=cellfun(@(m) padarray(m,[0 max(cellfun(@(n) size(n,2), e)) - size(m,2)],'post'), e,'UniformOutput',0);
uu=cell2mat(tt([1:d-1])')
suu=size(uu)
uu(:,((suu(2))+1))=sum(uu')'

but i faced a big problem during the implementation of the program that this command :

e{d} = nchoosek(b, d) has failed to continue as result of the number of possible choices and number of selected choices and finally the limitations:

When b = nchoosek(n,k) is sufficiently large, nchoosek displays a warning that the resultmight not be exact. In this case, the result is only accurate to 15 digits for double-precision inputs, or 8 digits for single-precision inputs.

C = nchoosek(v,k) is only practical for situations where length(v) is less than about 15.

that's where my vector consist of the hundreds of numbers which i want to do this process on. when i run the program , then matlab is being busy until giving me out of memory error in a time and takes along time without implementation of the program then i am forced to out of the program . i looked for a solution by help "out of memory" but i failed to find any solution then i tried to use anther command that's

combnk(v,k)

but it takes along time without implementation of the program then i am forced to out of the program too please please please , i want to practical solution to perform a lot of processes like this for my work . If the solution depends on the capabilities of my computer tell me about that computer specifications which performs this program easily , quickly and immediately note that my computer specifications are : win 7 64 bit 4 GB RAM 2.3 cpu i3