I need to create all a list of all possible states
3 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
V A
am 27 Apr. 2016
Kommentiert: Roger Stafford
am 28 Apr. 2016
I have discrete variables a_i=[1 -1]. I need to create a list of all states in system of N variables(# of states = 2^N). Or in other words I have a vector of length N, each component can have two values. How can I generate a list of all possible vectors?
For instance, for 3 variables I need to have
[1 1 1]
[1 1 -1]
[1 -1 1]
[-1 1 1]
[1 -1 -1]
[-1 1 -1]
[-1 -1 1]
[-1 -1 -1]
0 Kommentare
Akzeptierte Antwort
Kevin
am 27 Apr. 2016
I have written my own function to do what you are asking for. The trick is to use the MATLAB function ndgrid.
>> A = allcombs({[1 -1], [1 -1], [1 -1]})
A =
1 1 1
1 1 -1
1 -1 1
1 -1 -1
-1 1 1
-1 1 -1
-1 -1 1
-1 -1 -1
Here is the definition of my function allcombs.m:
function A = allcombs(experimentOutcomes)
experimentOutcomes = flipud(experimentOutcomes(:));
c = cell(1, numel(experimentOutcomes));
[c{:}] = ndgrid(experimentOutcomes{:});
c = fliplr(c);
A = cell2mat(cellfun(@(v)v(:), c, 'UniformOutput',false));
end
4 Kommentare
Kevin
am 27 Apr. 2016
But if N = 30, then
>> 2^30
ans =
1.0737e+09
So the matrix (that contains all possible combinations) will have 1 billion rows and 30 columns. Each matrix element takes 8 bytes. So total number of bytes ~= 240 GB.
Right?
Weitere Antworten (1)
Roger Stafford
am 27 Apr. 2016
A = zeros(2^N,N);
for k = 0:2^N-1
A(k+1,:) = 2*(dec2bin(k,N)-'0')-1;
end
2 Kommentare
Roger Stafford
am 28 Apr. 2016
If that is the limit on your array sizes, then no 'double' solution for N>=26 could work. The matrix you request as an output is that size. You could probably get up to N = 29 by using the 'uint8' format, but that would be as far as you could go.
Siehe auch
Kategorien
Mehr zu Operators and Elementary Operations finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!