Bugs in programing !!

Hi there guys,

Can anybody tell me what "bugs in programing" means?, and how to overcome this problem? I'm calculating a stiffness matrix of a rectangular element, this matrix should be symmetrical, but when I tested the symmetry by writing " a=K'-K ", I got "a" for some elements with some entries equal to a figure^-10 and for some other elements "a" is zeros(12,12) despite using the same loop. The reason behind that is said to be "bugs in programing".

[Adam]

The reason behind that is likely not 'bugs in programming' at all, it is a well documented effect of floating point maths which has been asked about numerous times on this forum and elsewhere on the web.

Floating point numbers cannot be represented 100% accurately so small errors creep into maths involving them.