4.2. Test Case 2: Griewangk Benchmark Function (Reference
of Data: [50])
This test case is a highly nonlinear and nonconvex
benchmark function with absolute minimum equal to
zero. The mathematical formulation of this function is
presented in (13) and its shape is shown in Figure 5.
f ðx1; x2Þ5
X2
k51
x2
k
4000
2P 2
k51
cosð
xkffiffiffi k
p Þ11
2600 xk 600 k51; 2
(13)
The results obtained for minimizing the Griewangk test
function are shown in Table 2 similar to Table 1. From
Table 2, it is seen that the MIN result of the proposed SSO
is zero and only six other methods, including PSOTVAC,
PSOIIW, FPSO, IHSA, IGSA, and RABC can reach this MIN
result, while 26 other methods have higher MIN index.
Moreover, MEAN and MAX indices of SSO are lower than
those of all other methods of Table 2. Finally, SSO has the
lowest computation time among all methods of Table 3.
These results clearly illustrate high effectiveness of the
proposed SSO for solving this benchmark function.