subtraction ele by ele

hi all,

consider any two matrix A and B of 3X3 . i want to subtract every element of A from each element of B one by one. kindly tell the command please.

[Stephen23]

MATLAB allows you to do this all at once using vectorized code, rather than one-by-one. This is faster, neater, and much less buggy code!

>> A = rand(3);
>> B = rand(3);
>> A - B
ans =
     -0.15016    -0.043791      0.13661
      0.74818      0.14698      0.12512
     -0.84361     -0.70274     0.041771

Answer 1

[Image Analyst]

Not sure what you mean so I'll offer the two possibilities:

result = A - B;

or

A = randi(100, 3, 3)
B = randi([1,9], 3, 3)
aVector = A(:)
bVector = B(:)
loopCounter = 1;
for k1 = 1 : length(aVector);
for k2 = 1 : length(bVector);
  result(loopCounter) = aVector(k1) - bVector(k2);
  loopCounter = loopCounter + 1;
end
end
% Print to command window
result

[Offroad Jeep]

wonderful................

[Image Analyst]

So, was it the second chunk of code (which is completely different than doing A-B) that did what you want?

Answer 2

[David Young]

-

[Star Strider]

@4 X 4 —

David Young’s answer isn’t blank but maximally laconic. It is the ‘minus’ sign that will work for equally-sized matrices.