Difference between revisions of "Initialisation"

From Adaptive Population based Simplex
Jump to: navigation, search
(Basic initialisation (i0))
(Population cost)
 
(One intermediate revision by the same user not shown)
Line 5: Line 5:
 
$N=\max\left(40+2\sqrt{D},\sqrt{40^{2}+\left(D+2\right)^{2}}\right)\label{eq:N_popsize}$
 
$N=\max\left(40+2\sqrt{D},\sqrt{40^{2}+\left(D+2\right)^{2}}\right)\label{eq:N_popsize}$
  
where $D$ is the dimension of the search space. Note that $N$ needs to be at least equal to $D+
+
where $D$ is the dimension of the search space. Note that $N$ needs to be at least equal to $D+1$.
  
 
We will need the volume $V(0)$ of the previous simplex. As no one has been defined yet, we simply set it to 0:<br />
 
We will need the volume $V(0)$ of the previous simplex. As no one has been defined yet, we simply set it to 0:<br />
Line 11: Line 11:
  
 
=== Population cost ===
 
=== Population cost ===
Evaluate the $N$ individuals. Save the best one as $Best$.
+
Evaluate the $N$ individuals, thanks to the function $f$ we are studying. Save the best one as $Best$.
  
 
The sum of all values (they are all supposed to be positive, which is always possible), is the initial ''population cost'' $C$. We are trying here to minimise it.
 
The sum of all values (they are all supposed to be positive, which is always possible), is the initial ''population cost'' $C$. We are trying here to minimise it.

Latest revision as of 17:55, 28 June 2013

Basic initialisation (i0)

Population size vs Dimension

Draw at random $N$ agents (positions) in the search space, according to an uniform distribution.

$N=\max\left(40+2\sqrt{D},\sqrt{40^{2}+\left(D+2\right)^{2}}\right)\tag{1}$

where $D$ is the dimension of the search space. Note that $N$ needs to be at least equal to $D+1$.

We will need the volume $V(0)$ of the previous simplex. As no one has been defined yet, we simply set it to 0:
$$V(0)=0$$

Population cost

Evaluate the $N$ individuals, thanks to the function $f$ we are studying. Save the best one as $Best$.

The sum of all values (they are all supposed to be positive, which is always possible), is the initial population cost $C$. We are trying here to minimise it.