Adding matrices, resulting matrix is only a copy of one of the matrices being added

I am attempting to add three matrices although when I do so, the resulting matrix is the same as one of the matrices being added rather than a combination of the three.

For example, if I am trying to add matrices A, B and C, when I add them, the contents of the resulting matrix are the same as A alone.

What is a possible explanation for this?

Answer 1

[Wayne King]

Are these large matrices? Can you show us? Of course it is possible that

 A = A+B+C

but that means that B+C must necessarily be the additive identity (matrix of zeros)

For example:

   A = randi([-5 5],10,10);
   B = randi([-3 3],10,10);
   C = -B;
   A+B+C

[Emma]

Each matrix is a 2400x2400 double, comprised of 0s and positive decimals which should add easily. I have also checked the contents of each matrix and they appear to be unique, so A+B+C should be different from any of the individual matrices.

Answer 2

[Walter Roberson]

This could happen if the values in B and C were much smaller than the values in A. For example, [1] + [1e-30] + [1e-50] is going to be [1]

[Emma]

Each value is between 0 and 1.

[Walter Roberson]

1e-30 and 1e-50 are both between 0 and 1.