What is the meaning of an "objective function" and "objective functionals"?

Question

Right now I am in front of these expressions

1. objective function

2. objective functionals

which seem to be very often used, but I've still not understood their meanings.

Answer 1

In general terms or simple english:

Objective: What is the goal?

Function: How to measure performance?

For mathematical details:

http://en.wikipedia.org/wiki/Objective_function

http://en.wikipedia.org/wiki/Optimization_problem

Answer 2

The concept of $objective$ $function$ is used in optimization. It denotes the function you want to minimize or maximize. It is used in many areas as in curve fit, regression, economics, ...

If there is any relevant area you would like to discuss, just post.

Just by the way, I was born in Dar El Beida (normal name hidden !).