2d Sphere
f 1 ( x ) = ‖ x → − ( − 1 , 0 , … , 0 ) ‖ f 2 ( x ) = ‖ x → − ( 1 , 0 , … , 0 ) ‖ {\displaystyle {\begin{aligned}&f_{1}(x)=\left\|{\vec {x}}-(-1,0,\ldots ,0)\right\|\\&f_{2}(x)=\left\|{\vec {x}}-(1,0,\ldots ,0)\right\|\\\end{aligned}}}
f 1 ( x ) = x f 2 ( x ) = ( 2 − x 1 / α ) α {\displaystyle {\begin{aligned}&f_{1}(x)=x\\&f_{2}(x)=\left(2-x^{1/\alpha }\right)^{\alpha }\\\end{aligned}}}
d ( x 1 ) = ( 2 − x 1 1 / α ) α − 1 x 1 1 / α − 1 {\displaystyle d(x_{1})=\left(2-x_{1}^{1/\alpha }\right)^{\alpha -1}x_{1}^{1/\alpha -1}}
Formulation f 1 = x 1 f 2 = g ⋅ ( 1.0 − f 1 g ) g ( x 2 , … , x n ) = 1.0 + 9 n − 1 ∑ i = 2 n x i 0 ≤ x i ≤ 1 , i = 1 , … , n {\displaystyle {\begin{aligned}&f_{1}=x_{1}\\&f_{2}=g\cdot \left(1.0-{\sqrt {\frac {f_{1}}{g}}}\right)\\&g(x_{2},\ldots ,x_{n})=1.0+{\frac {9}{n-1}}\sum \limits _{i=2}^{n}x_{i}\\&0\leq x_{i}\leq 1,i=1,\ldots ,n\\\end{aligned}}}
Pareto Front x 2 = 1 − x 1 {\displaystyle x_{2}=1-{\sqrt {x_{1}}}}
d ( x 1 ) = 3 4 x 1 1 / 4 {\displaystyle d(x_{1})={\frac {3}{4x_{1}^{1/4}}}}
b o p t ( a , c ) = 2 / 9 ( a + a ( a + 3 c ) ) + 1 / 3 c {\displaystyle b_{opt}(a,c)=2/9\left(\,a+\,{\sqrt {a(a+3\,c)}}\right)+1/3\,c}
a o p t ( r , b ) = 2 / 9 − 4 / 9 r + 2 / 9 1 − 2 r + r 2 + 3 b + 2 / 9 r 2 − 2 / 9 r 1 − 2 r + r 2 + 3 b + 1 / 3 b {\displaystyle a_{opt}(r,b)=2/9-4/9\,r+2/9\,{\sqrt {1-2\,r+r^{2}+3\,b}}+2/9\,r^{2}-2/9\,r{\sqrt {1-2\,r+r^{2}+3\,b}}+1/3\,b}
f 1 ( x → ) = x 1 f 2 ( x → ) = g ( x → ) [ 1 − x 1 / g ( x → ) − x 1 / g ( x → ) sin ( 10 π x 1 ) g ( x → ) = 1 + 9 n − 1 ( ∑ i = 2 n x i ) 0 ≤ x i ≤ 1 , i = 1 , … , n {\displaystyle {\begin{aligned}&f_{1}({\vec {x}})=x_{1}\\&f_{2}({\vec {x}})=g({\vec {x}})[1-{\sqrt {x_{1}/g({\vec {x}})}}-x_{1}/g({\vec {x}})\sin(10\pi x_{1})\\&g({\vec {x}})=1+{\frac {9}{n-1}}\left(\sum \limits _{i=2}^{n}{x_{i}}\right)\\&0\leq x_{i}\leq 1,{\text{ }}i=1,\ldots ,n\\\end{aligned}}}
( x 1 , x 2 ) {\displaystyle \displaystyle (x_{1},x_{2})} with x 1 ∈ F {\displaystyle x_{1}\in F} and x 2 = 1 − x 1 − x 1 ⋅ sin ( 10 π x 1 ) {\displaystyle x_{2}=1-{\sqrt {x_{1}}}-x_{1}\cdot \sin(10\pi x_{1})} where F = [ 0 , 0.0830015349 ] ∪ ( 0.1822287280 , 0.2577623634 ] ∪ ( 0.4093136748 , 0.4538821041 ] ∪ ( 0.6183967944 , 0.6525117038 ] ∪ ( 0.8233317983 , 0.8518328654 ] {\displaystyle {\begin{aligned}F=&[0,{\text{ }}0.0830015349]\cup {\text{ }}\\&(0.1822287280,{\text{ }}0.2577623634]\cup \\&(0.4093136748,{\text{ }}0.4538821041]\cup \\&(0.6183967944,{\text{ }}0.6525117038]\cup \\&(0.8233317983,{\text{ }}0.8518328654]\\\end{aligned}}}
d ( x 1 ) = C ⋅ 1 2 x + sin ( 10 π x ) + 10 x cos ( 10 π x ) π {\displaystyle d(x_{1})=C\cdot \,{\sqrt {\,{\frac {1}{2{\sqrt {x}}}}+\,\sin \left(10\,\pi \,x\right)+10\,x\cos \left(10\,\pi \,x\right)\pi }}}
f 1 ( x → ) = x 1 f 2 ( x → ) = ( 1 + g ( x → ) ) h ( f 1 ( x → ) , g ( x → ) ) g ( x → ) = 1 + 9 | x → | ∑ x i ∈ x → x i h ( f 1 ( x → ) , g ( x → ) ) = M − f 1 ( x → ) 1 + g ( x → ) ( 1 + sin ( 3 π f 1 ( x → ) ) ) 0 ≤ x i ≤ 1 , 1 ≤ i ≤ n {\displaystyle {\begin{aligned}f_{1}({\vec {x}})&=x_{1}\\f_{2}({\vec {x}})&=(1+g({\vec {x}}))h(f_{1}({\vec {x}}),g({\vec {x}}))\\g({\vec {x}})&=1+{\frac {9}{\left|{\vec {x}}\right|}}\sum \nolimits _{x_{i}\in {\vec {x}}}{x_{i}}\\h(f_{1}({\vec {x}}),g({\vec {x}}))&=M-{\frac {f_{1}({\vec {x}})}{1+g({\vec {x}})}}(1+\sin(3\pi f_{1}({\vec {x}})))\\&0\leq x_{i}\leq 1,1\leq i\leq n\\\end{aligned}}}
( x 1 , x 2 ) {\displaystyle \displaystyle (x_{1},x_{2})} with x 1 ∈ F {\displaystyle x_{1}\in F} and x 2 = 4 − x 1 ( 1 + sin ( 3 π x 1 ) ) {\displaystyle \displaystyle x_{2}=4-x_{1}(1+\sin(3\pi x_{1}))} where F = [ 0 , 0.2514118360 ] ∪ ( 0.6316265307 , 0.8594008566 ] ∪ ( 1.3596178367 , 1.5148392681 ] ∪ ( 2.0518383519 , 2.116426807 ] {\displaystyle {\begin{aligned}F=&[0,{\text{ }}0.2514118360]\cup {\text{ }}\\&(0.6316265307,{\text{ }}0.8594008566]\cup \\&(1.3596178367,{\text{ }}1.5148392681]\cup \\&(2.0518383519,{\text{ }}2.116426807]\\\end{aligned}}}
d ( x 1 ) = C ⋅ 1 + sin ( 3 π x 1 ) + 3 π x 1 cos ( 3 π x 1 ) {\displaystyle d(x_{1})=C\cdot {\sqrt {1+\sin(3\pi x_{1})+3\pi x_{1}\cos(3\pi x_{1})}}}
b o p t ( a , c ) = 1 / 3 c + 1 / 3 c 2 + 3 a 2 {\displaystyle b_{opt}(a,c)=1/3\,c+1/3\,{\sqrt {c^{2}+3\,a^{2}}}}
d ( x 2 ) = 3 2 x 1 {\displaystyle d(x_{2})={\frac {3}{2}}{\sqrt {x_{1}}}}
f 1 ( x → ) = 1 − e − 4 x 1 ⋅ sin 6 ( 6 π x 1 ) f 2 ( x → ) = g ( x → ) ⋅ [ ( ∑ i = 2 n x i ) ╱ ( n − 1 ) ] 0.25 0 ≤ x i ≤ 1 , i = 1 , … , n {\displaystyle {\begin{aligned}&f_{1}({\vec {x}})=1-e^{-4x_{1}}\cdot \sin ^{6}(6\pi x_{1})\\&f_{2}({\vec {x}})=g({\vec {x}})\cdot \left[{}^{\left(\sum \limits _{i=2}^{n}{x_{i}}\right)}\!\!\diagup \!\!{}_{(n-1)}\;\right]^{0.25}\\&0\leq x_{i}\leq 1,i=1,\ldots ,n\\\end{aligned}}}
x 2 = 1 − x 1 2 {\displaystyle \displaystyle x_{2}=1-x_{1}^{2}} with x 1 ∈ [ arctan 9 π 6 π ≈ 0.0815 , 1 ] {\displaystyle x_{1}\in [{\frac {\arctan {9\pi }}{6\pi }}\approx 0.0815,1]}
δ ( x 1 ) = 3 2 ( 1 − arctan ( 9 π ) 6 π 3 / 2 ) − 1 x 1 {\displaystyle \delta (x_{1})={\frac {3}{2}}\left(1-{\frac {\arctan(9\pi )}{6\pi }}^{3/2}\right)^{-1}{\sqrt {x_{1}}}}
f 1 ( x → ) = 1 2 x 1 ( 1 + g ( x → ) ) f 2 ( x → ) = 1 2 ( 1 − x 1 ) ( 1 + g ( x → ) ) g ( x → ) = 100 [ | x → | + ∑ x i ∈ x → ( x 1 − 0.5 ) 2 − cos ( 20 ⋅ π ( x i − 0.5 ) ) ] 0 ≤ x i ≤ 1 , i = 1 , … , n {\displaystyle {\begin{aligned}&f_{1}({\vec {x}})={\frac {1}{2}}x_{1}(1+g({\vec {x}}))\\&f_{2}({\vec {x}})={\frac {1}{2}}(1-x_{1})(1+g({\vec {x}}))\\&g({\vec {x}})=100\left[\left|{\vec {x}}\right|+\sum \nolimits _{x_{i}\in {\vec {x}}}{(x_{1}-0.5)^{2}}-\cos(20\cdot \pi (x_{i}-0.5))\right]\\&0\leq x_{i}\leq 1,i=1,\ldots ,n\\\end{aligned}}}
x 2 = 1 2 − x 1 {\displaystyle x_{2}={\frac {1}{2}}-x_{1}}
d ( x 1 ) = 2 {\displaystyle \displaystyle d(x_{1})=2}
x 2 = 1 − x 1 2 {\displaystyle x_{2}={\sqrt {1-x_{1}^{2}}}}
f 1 ( x → ) = ( 1 + g ( x → ) ) cos ( x 1 π 2 ) f 2 ( x → ) = ( 1 + g ( x → ) ) sin ( x 1 π 2 ) g ( x → ) = ∑ x i ∈ x → ( x i − 0.5 ) 2 0 ≤ x i ≤ 1 , i = 1 , … , n {\displaystyle {\begin{aligned}f_{1}({\vec {x}})&=(1+g({\vec {x}}))\cos \left(x_{1}{\frac {\pi }{2}}\right)\\f_{2}({\vec {x}})&=(1+g({\vec {x}}))\sin \left(x_{1}{\frac {\pi }{2}}\right)\\g({\vec {x}})&=\sum \nolimits _{x_{i}\in {\vec {x}}}{(x_{i}-0.5)^{2}}\\&0\leq x_{i}\leq 1,i=1,\ldots ,n\\\end{aligned}}}
f 1 ( x → ) = ( 1 + g ( x → ) ) cos ( x 1 π 2 ) f 2 ( x → ) = ( 1 + g ( x → ) ) sin ( x 1 π 2 ) g ( x → ) = 100 ⋅ [ | x → | + ∑ x i ∈ x → ( x i − 0.5 ) 2 − cos ( 20 π ( x i − 0.5 ) ) ] 0 ≤ x i ≤ 1 , i = 1 , … , n {\displaystyle {\begin{aligned}&f_{1}({\vec {x}})=(1+g({\vec {x}}))\cos \left(x_{1}{\frac {\pi }{2}}\right)\\&f_{2}({\vec {x}})=(1+g({\vec {x}}))\sin \left(x_{1}{\frac {\pi }{2}}\right)\\&g({\vec {x}})=100\cdot [\left|{\vec {x}}\right|+\sum \nolimits _{x_{i}\in {\vec {x}}}{(x_{i}-0.5)^{2}}-\cos(20\pi (x_{i}-0.5))]\\&0\leq x_{i}\leq 1,i=1,\ldots ,n\\\end{aligned}}}
f 1 ( x → ) = ( 1 + g ( x → ) ) cos ( x 1 α π 2 ) f 2 ( x → ) = ( 1 + g ( x → ) ) sin ( x 1 α π 2 ) g ( x → ) = ∑ x i ∈ x → ( x i − 0.5 ) 2 α = 100 0 ≤ x i ≤ 1 , i = 1 , … , n {\displaystyle {\begin{aligned}&f_{1}({\vec {x}})=(1+g({\vec {x}}))\cos \left(x_{1}^{\alpha }{\frac {\pi }{2}}\right)\\&f_{2}({\vec {x}})=(1+g({\vec {x}}))\sin \left(x_{1}^{\alpha }{\frac {\pi }{2}}\right)\\&g({\vec {x}})=\sum \nolimits _{x_{i}\in {\vec {x}}}{(x_{i}-0.5)^{2}}\\&\alpha =100\\&0\leq x_{i}\leq 1,i=1,\ldots ,n\\\end{aligned}}}