array multiplication with a negative value

A=[0,-2.2,-3.3,-25;1.2,0,-1.1,12;2,-8,8,0] my answer is to be A=[0,-2.2,-3.3,-25;-1.2,0,-1.1,-12;-2,-8,-8,0]. I need to convert the values in A which is greater than zero as -A. I have used if A(A > 0) A=-A; end This is not working. Suggest some points

Answer 1

[Andrei Bobrov]

t = A > 0;
A(t) = -A(t);

or

A = -abs(A);

[Bathrinath]

Thank you sir