# Using conditional IF statement

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summyia qamar on 19 Dec 2016
Answered: Steven Lord on 19 Dec 2016
I have a matrix A and I generate B=randi([0,1],7,3).I want C=A*B only if sum of each row of B=1..I tried this..
A=[1 0 0 1 0 1 1
0 1 1 1 0 0 1
1 0 0 1 1 0 0
1 0 0 0 1 0 1
1 1 0 0 0 1 0
0 1 0 0 0 1 1]
for k=1:numIterations
B=randi([0,1],7,3);
if sum(B,2)==1;
C=A*B;
end
end
how to use IF condition in this case?
##### 2 CommentsShowHide 1 older comment
summyia qamar on 19 Dec 2016
thankyou..I skipped C(k)

Roger Stafford on 19 Dec 2016
if all(sum(B,2)==1)
summyia qamar on 19 Dec 2016
I tried this.
A=[1 0 0 1 0 1 1
0 1 1 1 0 0 1
1 0 0 1 1 0 0
1 0 0 0 1 0 1
1 1 0 0 0 1 0
0 1 0 0 0 1 1];
for k=1:numIterations
B=randi([0,1],7,3);
if all(sum(B,2)==1)
C=A*B
end
end
[B C(ones(7,1))]
and result is C =
1 2 1
0 4 0
2 1 0
2 1 0
1 1 1
0 2 1
ans =
0 0 1 1
1 0 0 1
1 0 1 1
1 1 0 1
1 0 1 1
1 0 0 1
0 0 1 1
row 3 is not upto the condition

Steven Lord on 19 Dec 2016
Don't generate B randomly, or at least not the way you're generating it. Your constraint on B is that each row must have exactly one nonzero value. So generate the index of the column in each row that contains the nonzero value and use that to generate a B matrix that is guaranteed to satisfy your constraint.
numRows = 10;
numCols = 5;
rowind = (1:numRows).';
colind = randi(numCols, numRows, 1);
B = accumarray([rowind, colind], 1, [numRows, numCols]);
check = all(sum(B, 2) == 1)
The sz input to accumarray is necessary for the (unlikely) case where no row has a 1 in the last column, to ensure B is the correct size.