
252 Monarch Butterfly Optimization
flutter staying in region 1 and total number of monarch butterfly population
respectively. Similarly, the butterflies found in region 2 are considered to be
‘subpopulation 2’, P
n2
= P
n
− P
n1
.
This migration process of butterflies is mathematically expressed as
s
ij
(t + 1) = s
r
1
,j
(t) (19.1)
where, s
ij
(t + 1), represents the jth position element/variable of the ith but-
terfly in t + 1 generation, whereas, s
r
1
,j
(t), represents the jth element of s
r
1
which is the new position of monarch butterfly r
1
of current generation t. The
butterfly r
1
is randomly selected from subpopulation 1 or region 1.
For decision making, a random number