《Unified theory of augmented Lagrangian methods for constrained global optimization》增广拉格朗日函数统一为一下三种形式:
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L_P(x,\lambda,c)=\left\{\begin{aligned}&f(x)+\frac{1}{c}\sum\limits_{i=1}^mP(cg_i(x),\lambda_i),&&x\in\Omega_c(a)\\&+\infty,&&x\notin\Omega_c(a)\end{aligned}\right.
LP(x,λ,c)=⎩⎪⎪⎨⎪⎪⎧f(x)+c1i=1∑mP(cgi(x),λi),+∞,x∈Ωc(a)x∈/Ωc(a)
L R ( x , λ , c ) = { f ( x ) + 1 c ∑ i = 1 m R ( c g i ( x ) , λ i ) , x ∈ Ω c ( a ) + ∞ , x ∉ Ω c ( a ) L_R(x,\lambda,c)=\left\{\begin{aligned}&f(x)+\frac{1}{c}\sum\limits_{i=1}^mR(cg_i(x),\lambda_i),&&x\in\Omega_c(a)\\&+\infty,&&x\notin\Omega_c(a)\end{aligned}\right. LR(x,λ,c)=⎩⎪⎪⎨⎪⎪⎧f(x)+c1i=1∑mR(cgi(x),λi),+∞,x∈Ωc(a)x∈/Ωc(a)
L p ( x , λ , c ) = { f ( x ) + 1 c ∑ i = 1 m V ( c g i ( x ) , λ i ) , x ∈ Ω c ( a ) + ∞ , x ∉ Ω c ( a ) L_p(x,\lambda,c)=\left\{\begin{aligned}&f(x)+\frac{1}{c}\sum\limits_{i=1}^mV(cg_i(x),\lambda_i),&&x\in\Omega_c(a)\\&+\infty,&&x\notin\Omega_c(a)\end{aligned}\right. Lp(x,λ,c)=⎩⎪⎪⎨⎪⎪⎧f(x)+c1i=1∑mV(cgi(x),λi),+∞,x∈Ωc(a)x∈/Ωc(a)
下面分别介绍以上三种统一形式的增广拉格朗日函数
L P ( x , λ , c ) = { f ( x ) + 1 c ∑ i = 1 m P ( c g i ( x ) , λ i ) , x ∈ Ω c ( a ) + ∞ , x ∉ Ω c ( a ) L_P(x,\lambda,c)=\left\{\begin{aligned}&f(x)+\frac{1}{c}\sum\limits_{i=1}^mP(cg_i(x),\lambda_i),&&x\in\Omega_c(a)\\&+\infty,&&x\notin\Omega_c(a)\end{aligned}\right. LP(x,λ,c)=⎩⎪⎪⎨⎪⎪⎧f(x)+c1i=1∑mP(cgi(x),λi),+∞,x∈Ωc(a)x∈/Ωc(a)
其中 P ( s , t ) P(s,t) P(s,t) 在 R a × R + \mathbb R_a\times \mathbb R_+ Ra×R+ 对于第一个变量 s ∈ R a s\in\mathbb R_a s∈Ra 上连续可微
H 1 : P ( ⋅ , t ) H_1:P(\cdot,t) H1:P(⋅,t) 对于 s s s 是单调递增,满足:
P ( 0 , t ) = 0 , ∀ t ∈ R + ; P ( s , 0 ) ≥ 0 , ∀ s ∈ R a ; P ( s , t ) → + ∞ ( t → + ∞ ) , f o r s > 0. P(0,t)=0,\;\forall t\in \mathbb R_+;\\P(s,0)\ge0,\;\forall s\in \mathbb R_a;\\P(s,t)\rightarrow+\infty(t\rightarrow+\infty),\;for\;s>0. P(0,t)=0,∀t∈R+;P(s,0)≥0,∀s∈Ra;P(s,t)→+∞(t→+∞),fors>0.
H 2 : H_2: H2: 存在连续的函数 r ( t ) r(t) r(t)
P ( s , t ) ≥ r ( t ) , ∀ ( s , t ) ∈ R a × R + P(s,t)\ge r(t),\;\forall(s,t)\in\mathbb R_a\times\mathbb R_+ P(s,t)≥r(t),∀(s,t)∈Ra×R+
H 3 : H_3: H3: 如果 a = + ∞ a=+\infty a=+∞,那么 P ( s , t ) s → + ∞ ( s → − ∞ ) \frac{P(s,t)}{s}\rightarrow+\infty(s\rightarrow-\infty) sP(s,t)→+∞(s→−∞) 对于任何 t ∈ R + t\in R_+ t∈R+
H 4 : P s ′ ( s , t ) ≤ t , ∀ s < 0 H_4:P^\prime_s(s,t)\le t,\forall s<0 H4:Ps′(s,t)≤t,∀s<0 并且 P s ′ ( s , t ) → 0 ( s → − ∞ ) P^\prime_s(s,t)\rightarrow0(s\rightarrow-\infty) Ps′(s,t)→0(s→−∞) 对于任何 t ∈ S ⊂ R + t\in S\subset \mathbb R_+ t∈S⊂R+
其中 S S S 是一个有界集
L P 1 ( x , λ , c ) = f ( x ) + 1 c ∑ i = 1 m P 1 ( c g i ( x ) , λ i ) , L_{P1}(x,\lambda,c)=f(x)+\frac{1} {c}\sum\limits_{i=1}^mP_1(cg_i(x),\lambda_i), LP1(x,λ,c)=f(x)+c1i=1∑mP1(cgi(x),λi),
( a = + ∞ ) (a=+\infty) (a=+∞) 其中 P 1 ( s , t ) = ( m a x 0 , ϕ 1 ( s ) + t ) 2 − t 2 , ( s , t ) ∈ R × R + P_1(s,t)=(max{0,\phi_1(s)+t})^2-t^2,(s,t)\in \mathbb R\times\mathbb R_+ P1(s,t)=(max0,ϕ1(s)+t)2−t2,(s,t)∈R×R+ 函数 ϕ 1 ( ⋅ ) \phi_1(\cdot) ϕ1(⋅) 满足以下条件:
- ϕ 1 ( ⋅ ) \phi_1(\cdot) ϕ1(⋅) 是一个二次连续可微分,并且在 R \mathbb R R 上为凸函数;
- ϕ 1 ( 0 ) = 0 , ϕ 1 ′ ( 0 ) = 1 \phi_1(0)=0, \phi_1^\prime(0)=1 ϕ1(0)=0,ϕ1′(0)=1;
- lim s → − ∞ ϕ 1 ′ ( s ) > 0 \lim_{s\rightarrow-\infty}\phi_1^{\prime}(s)>0 lims→−∞ϕ1′(s)>0.
L P 2 ( x , λ , c ) = f ( x ) + 1 c ∑ i = 1 m P 2 ( c g i ( x ) , λ i ) , L_{P2}(x,\lambda,c)=f(x)+\frac{1} {c}\sum\limits_{i=1}^mP_2(cg_i(x),\lambda_i), LP2(x,λ,c)=f(x)+c1i=1∑mP2(cgi(x),λi),
( a = + ∞ ) (a=+\infty) (a=+∞) 其中 P 2 ( s , t ) = min τ ≥ s { t τ + ϕ 2 ( τ ) } , ( s , t ) ∈ R × R + P_2(s,t)=\min_{\tau\ge s}\{t\tau+\phi_2(\tau)\},(s,t)\in \mathbb R\times\mathbb R_+ P2(s,t)=minτ≥s{tτ+ϕ2(τ)},(s,t)∈R×R+ 函数 ϕ 2 ( ⋅ ) \phi_2(\cdot) ϕ2(⋅) 满足以下条件:
- ϕ 2 ( ⋅ ) \phi_2(\cdot) ϕ2(⋅) 是一个二次连续可微分,并且在 R \mathbb R R 上为凸函数;
- ϕ 2 ( 0 ) = 0 , ϕ 2 ′ ( 0 ) = 0 , ϕ 2 ′ ′ > 0 \phi_2(0)=0, \phi_2^\prime(0)=0,\phi_2^{\prime\prime}>0 ϕ2(0)=0,ϕ2′(0)=0,ϕ2′′>0;
- ϕ 2 ( s ) ∣ s ∣ → + ∞ , ( ∣ s ∣ → + ∞ ) \frac{\phi_2(s)}{|s|}\rightarrow+\infty,(|s|\rightarrow+\infty) ∣s∣ϕ2(s)→+∞,(∣s∣→+∞)
L P 3 ( x , λ , c ) = f ( x ) + 1 c ∑ i = 1 m P 3 ( c g i ( x ) , λ i ) , L_{P3}(x,\lambda,c)=f(x)+\frac{1} {c}\sum\limits_{i=1}^mP_3(cg_i(x),\lambda_i), LP3(x,λ,c)=f(x)+c1i=1∑mP3(cgi(x),λi),
( a = + ∞ ) (a=+\infty) (a=+∞) 其中 P 3 ( s , t ) = t ϕ 3 ( s ) + ξ ( s ) , ( s , t ) ∈ R × R + P_3(s,t)=t\phi_3(s)+\xi(s),(s,t)\in \mathbb R\times\mathbb R_+ P3(s,t)=tϕ3(s)+ξ(s),(s,t)∈R×R+ 函数 ϕ 3 ( ⋅ ) \phi_3(\cdot) ϕ3(⋅) 满足以下条件:
- ϕ 3 ( ⋅ ) \phi_3(\cdot) ϕ3(⋅) 是一个二次连续可微分,并且在 R \mathbb R R 上为凸函数;
- ϕ 3 ( 0 ) = 0 , ϕ 3 ′ ( 0 ) = 0 , ϕ 3 ′ ′ > 0 \phi_3(0)=0, \phi_3^\prime(0)=0,\phi_3^{\prime\prime}>0 ϕ3(0)=0,ϕ3′(0)=0,ϕ3′′>0;
- lim s → − ∞ ϕ 3 ( s ) > − ∞ , lim s → − ∞ ϕ 3 ′ ( s ) = 0 \lim_{s\rightarrow-\infty}\phi_3(s)>-\infty,\lim_{s\rightarrow-\infty}\phi^{\prime}_3(s)=0 lims→−∞ϕ3(s)>−∞,lims→−∞ϕ3′(s)=0
并且 ξ ( ⋅ ) \xi(\cdot) ξ(⋅) 满足如下条件:
- ξ ( ⋅ ) \xi(\cdot) ξ(⋅) 是二次连续可微分并且在 R \mathbb R R 上为凸函数;
- s ≤ 0 s\le0 s≤0 时 ξ ( s ) = 0 \xi(s)=0 ξ(s)=0, s > 0 s>0 s>0 时 ξ ( s ) > 0 \xi(s)>0 ξ(s)>0
- ξ ( s ) s → + ∞ , ( s → + ∞ ) \frac{\xi(s)}{s}\rightarrow+\infty,(s\rightarrow+\infty) sξ(s)→+∞,(s→+∞)
L P 4 ( x , λ , c ) = { f ( x ) + 1 c ∑ i = 1 m P 4 ( c g i ( x ) , λ i ) , x ∈ Ω c ( 1 ) + ∞ , x ∉ Ω c ( 1 ) L_{P4}(x,\lambda,c)=\left\{\begin{aligned}&f(x)+\frac{1}{c}\sum\limits_{i=1}^mP_4(cg_i(x),\lambda_i),&&x\in\Omega_c(1)\\&+\infty,&&x\notin\Omega_c(1)\end{aligned}\right. LP4(x,λ,c)=⎩⎪⎪⎨⎪⎪⎧f(x)+c1i=1∑mP4(cgi(x),λi),+∞,x∈Ωc(1)x∈/Ωc(1)
( a = 1 ) (a=1) (a=1) 其中 P 4 ( s , t ) = t ϕ 4 ( s ) , ( s , t ) ∈ R × R + P_4(s,t)=t\phi_4(s),(s,t)\in \mathbb R\times\mathbb R_+ P4(s,t)=tϕ4(s),(s,t)∈R×R+ 函数 ϕ 4 ( ⋅ ) \phi_4(\cdot) ϕ4(⋅) 满足以下条件:
- ϕ 4 ( ⋅ ) \phi_4(\cdot) ϕ4(⋅) 是一个二次连续可微分,并且在 R 1 \mathbb R_1 R1 上为凸函数;
- ϕ 4 ( 0 ) = 0 , ϕ 4 ′ ( 0 ) = 1 , ϕ 4 ( 0 ) ′ ′ > 0 \phi_4(0)=0, \phi_4^\prime(0)=1,\phi_4(0)^{\prime\prime}>0 ϕ4(0)=0,ϕ4′(0)=1,ϕ4(0)′′>0;
- lim s → − ∞ ϕ 4 ( s ) > − ∞ , lim s → − ∞ ϕ 4 ′ ( s ) = 0 \lim_{s\rightarrow-\infty}\phi_4(s)>-\infty,\lim_{s\rightarrow-\infty}\phi^{\prime}_4(s)=0 lims→−∞ϕ4(s)>−∞,lims→−∞ϕ4′(s)=0
L R ( x , λ , c ) = { f ( x ) + 1 c ∑ i = 1 m R ( c g i ( x ) , λ i ) , x ∈ Ω c ( a ) + ∞ , x ∉ Ω c ( a ) L_R(x,\lambda,c)=\left\{\begin{aligned}&f(x)+\frac{1}{c}\sum\limits_{i=1}^mR(cg_i(x),\lambda_i),&&x\in\Omega_c(a)\\&+\infty,&&x\notin\Omega_c(a)\end{aligned}\right. LR(x,λ,c)=⎩⎪⎪⎨⎪⎪⎧f(x)+c1i=1∑mR(cgi(x),λi),+∞,x∈Ωc(a)x∈/Ωc(a)
其中 R ( s , t ) R(s,t) R(s,t) 在 R a × R + \mathbb R_a\times\mathbb R_+ Ra×R+ 是连续,并且在 s ∈ R a s\in \mathbb R_a s∈Ra 上是连续可微分的。
假定函数 R ( s , t ) R(s,t) R(s,t) 有以下性质:
H 1 ′ : H_1^\prime: H1′: 和 H 1 H_1 H1 相同;
H 2 ′ : H_2^\prime: H2′: 对于任意给定的 t ∈ R + , R ( s , t ) s → 0 ( s → − ∞ ) t\in \mathbb R_+,\frac{R(s,t)}{s}\rightarrow 0(s\rightarrow-\infty) t∈R+,sR(s,t)→0(s→−∞)
H 3 ′ : H_3^\prime: H3′: 和 H 1 H_1 H1 相同;
H 4 ′ H_4^\prime H4′ 和 H 1 H_1 H1 相同。
L R 1 ( x , λ , c ) = { f ( x ) + 1 c ∑ i = 1 m R 1 ( c g i ( x ) , λ i ) , x ∈ Ω c ( 1 ) + ∞ , x ∉ Ω c ( 1 ) L_{R1}(x,\lambda,c)=\left\{\begin{aligned}&f(x)+\frac{1}{c}\sum\limits_{i=1}^mR_1(cg_i(x),\lambda_i),&&x\in\Omega_c(1)\\&+\infty,&&x\notin\Omega_c(1)\end{aligned}\right. LR1(x,λ,c)=⎩⎪⎪⎨⎪⎪⎧f(x)+c1i=1∑mR1(cgi(x),λi),+∞,x∈Ωc(1)x∈/Ωc(1)
( a = 1 ) (a=1) (a=1) 其中 R 1 ( s , t ) = t φ ( s ) , ( s , t ) ∈ R × R + R_1(s,t)=t\varphi(s),(s,t)\in \mathbb R\times\mathbb R_+ R1(s,t)=tφ(s),(s,t)∈R×R+ 函数 φ ( ⋅ ) \varphi(\cdot) φ(⋅) 满足以下条件:
- φ ( ⋅ ) \varphi(\cdot) φ(⋅) 是一个二次连续可微分,并且在 R 1 \mathbb R_1 R1 上为凸函数;
- φ ( 0 ) = 0 , φ ′ ( 0 ) = 1 , φ ′ ′ ( 0 ) > 0 \varphi(0)=0, \varphi^\prime(0)=1,\varphi^{\prime\prime}(0)>0 φ(0)=0,φ′(0)=1,φ′′(0)>0;
- lim s → − ∞ φ ( s ) s = 0 , lim s → − ∞ φ ′ ( s ) = 0 \lim_{s\rightarrow-\infty}\frac{\varphi(s)}{s}=0,\lim_{s\rightarrow-\infty}\varphi^\prime(s)=0 lims→−∞sφ(s)=0,lims→−∞φ′(s)=0.
L p ( x , λ , c ) = { f ( x ) + 1 c ∑ i = 1 m V ( c g i ( x ) , λ i ) , x ∈ Ω c ( a ) + ∞ , x ∉ Ω c ( a ) L_p(x,\lambda,c)=\left\{\begin{aligned}&f(x)+\frac{1}{c}\sum\limits_{i=1}^mV(cg_i(x),\lambda_i),&&x\in\Omega_c(a)\\&+\infty,&&x\notin\Omega_c(a)\end{aligned}\right. Lp(x,λ,c)=⎩⎪⎪⎨⎪⎪⎧f(x)+c1i=1∑mV(cgi(x),λi),+∞,x∈Ωc(a)x∈/Ωc(a)
其中 V ( s , t ) V(s,t) V(s,t) 在 R a × R + \mathbb R_a\times\mathbb R_+ Ra×R+ 是连续,并且在 s ∈ R a s\in \mathbb R_a s∈Ra 上是连续可微分的。
假定函数 V ( s , t ) V(s,t) V(s,t) 有以下性质:
H 1 ′ ′ : V ( ⋅ , t ) H_1^{\prime\prime}:V(\cdot,t) H1′′:V(⋅,t) 是单调递增,并且对于 s 是凸的,满足:
V ( 0 , t ) = 0 , ∀ t ∈ R + ; V ( s , t ) ≥ s t , ∀ ( s , t ) ∈ R a × R + V(0,t)=0,\;\forall t\in\mathbb R_+;V(s,t)\ge st,\;\forall(s,t)\in\mathbb R_a\times R_+ V(0,t)=0,∀t∈R+;V(s,t)≥st,∀(s,t)∈Ra×R+
H 2 ′ ′ : H_2^{\prime\prime}: H2′′: 和 H 2 H_2 H2 相同;
H 3 ′ ′ : H_3^{\prime\prime}: H3′′: 如果 a = + ∞ a=+\infty a=+∞ 那么对于任意 t ∈ S ⊂ R + t\in S\subset \mathbb R_+ t∈S⊂R+ V ( s , t ) s → + ∞ ( s → + ∞ ) \frac{V(s,t)}{s}\rightarrow+\infty(s\rightarrow+\infty) sV(s,t)→+∞(s→+∞),其中 S 是 R + \mathbb R_+ R+ 的任意无界闭集(any closed unbounded set);
H 4 ′ ′ : H_4^{\prime\prime}: H4′′: V ′ ( s , t ) > 0 , ∀ t > 0 V^\prime(s,t)>0, \forall t>0 V′(s,t)>0,∀t>0,对于任意 t ∈ S ⊂ R + t\in S\subset \mathbb R_+ t∈S⊂R+ V s ′ ( s , t ) → 0 ( s → − ∞ ) V^\prime_s(s,t)\rightarrow0(s\rightarrow-\infty) Vs′(s,t)→0(s→−∞),其中 S 是 R + \mathbb R_+ R+ 的任意无界集。