MATLAB: Generating vectors of length N with only -1s and 1s.

randomvectors

I want to generate some M number of vectors of length N with the entries restricted to -1s and 1s and the vectors should not be repetitive. Is it possible to do so? If yes, how?

Best Answer

>> M = 5;
>> N = 19;
>> randi(0:1,M,N)*2-1
ans =
  -1   1  -1   1  -1  -1   1  -1   1  -1  -1   1  -1   1   1  -1  -1   1   1
   1  -1  -1  -1  -1   1  -1  -1   1  -1  -1   1  -1  -1   1   1   1  -1   1
  -1   1  -1   1   1   1   1  -1   1  -1  -1  -1   1  -1   1   1   1   1  -1
   1  -1  -1   1  -1   1  -1  -1  -1  -1  -1   1  -1   1  -1   1   1   1  -1
  -1  -1   1  -1  -1  -1   1   1   1   1   1  -1  -1   1   1   1   1   1   1

Related Solutions

MATLAB: Counting consecutive occurences of 1s and -1s

The first step below counts all consecutive numbers. The second step eliminates the 0-counts.

A = [0 0 1 1 1 1 0 0 0 -1 -1 -1 0 1 1 0 ]; 
changeIdx = [1,diff(A)]~=0; 
counts = histcounts(cumsum(changeIdx),1:sum(changeIdx)+1); 
consecutiveCounts = [A(changeIdx)',counts']
% Result:
consecutiveCounts =
     0     2            %First there are 2 zeros
     1     4            %then 4 ones
     0     3            %then 3 zeros
    -1     3            %then 3 negative ones
     0     1            % etc...
     1     2
     0     1

To get the vector you described, eliminate the 0-counts and multiply by the sign of the value in A so counts of negative numbers are negative.

  consecutiveCounts(consecutiveCounts(:,1)~=0,2)' .* sign(consecutiveCounts(consecutiveCounts(:,1)~=0,1))'
ans =
     4    -3     2

MATLAB: How to convert a 64 bit, two’s complement value(binary vector)[ 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1] into a signed integer

swapbytes(typecast(uint8(bin2dec(char(reshape(fliplr(A),8,[]).' + '0'))),'int64'))

Best Answer

Related Solutions

MATLAB: Counting consecutive occurences of 1s and -1s

MATLAB: How to convert a 64 bit, two’s complement value(binary vector)[ 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1] into a signed integer

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