formulations - mit opencourseware · 2020-01-04 · formulations author: prof. dimitris bertsimas...
TRANSCRIPT
Formula,tionn: Lcc.
Ctcomct,ry: Lcc. 2-4
Simplex l\lcthoi:l: Lcc. 5-8
Thcory: Lc,:.
.-inalysin: Lei:.
Robust Lcc.
Large ncalc ol:,timizat,ion: Lcc.
Flo~is : Lcc. 16-17
The Ellipsi:,ii:l methi:,,$: Lcc. 18-19
1:)oint mcthoi:ls: Lcc. 20-21
Scmii:lcfinitc opt,imizatii:,n: Lcc.
~ i ~ , b l~c tc Opt,imizatii:,n: Lcc. 24-2;
Requirements
30%)
Mii:ltcrm 30%)
Final
Iml:,ortant brakcr: cont,ribut,ions t,o ,class
Lnc CPLEX fi:n si:,lving ol:,timiza,tion problems
of Optimizatio~l
LOPS Arisc?
Examplcs Fi:,rmulatii:,ns
1 Structure of Class
I
Duality
Sensitivity
9-11
12
Optimization: 13
14-15
Nctmork
Interior
22 . ..
2
Homcmorkn:
Exam:
Exam: 40%
tic
of
3 Lecture Outline
History
Whcrc
of
Opti~rlization
Fermat,
mi11 f(r) x : scalar
Euler,
nlin ~(sI, r,")
s.t,. (Jk(1.1,. . : r,") = 0 k = 1, . 77L
Lagrange Prol:,lcms in in fin it,^ dimcnsii:,ns, iralirulus variat,ions.
Nonlinear Optirrlizatiovl
The general
Linear
Forlnt~lat,ioli mininlizc 31.1 + 1.2
sul,jcct ti:, 1.1 2 21.1 1.2 2 1.1 2 >
~ninimizc c'z sul,jcct ti:, Az 2
z 2 0
4
6
History of
1638: Newton, 1670
1755
Lagrange, 1707 . . . .
. . ,.
Euler, of
5
5.1 problem
What is Optimization?
6.1
+ 21.2 2 + 3
0.1.2 0
h
Tlie pre-algorit,hmic
Fonrier, Mct,hoil for synbcm linear inc,:lualit,ics.
de Val1i.e Poussirl simplcx-like mcthoi:l fin ol,jcct,ivc functii:,n wit,h al:,ii:,- lute
vo11 Nenlnann, 1028 game t,hcory, iluality.
Farkas, Minkowski: Caratl~i.odory, Fi:,un,Sa,tionn
Tlie lnoderll
Dantzig. 51ml,lcx mcthoil
Applicat,ions.
Large Siralc Opt,imizat,ion.
thci:,ry.
The cllipsi:,ii:l algi:,rit,hm.
pi,int algi:,rit,hmn.
Scnlidcfinit,c all<\ ~ ~ t i ~ n i r a t i o n .
Ri:,bust Ol:,timizat,ion.
8 LOPS
Applicabilit,y
Transportat,ion
traffic ci:,nt,ri:,l, Crew schci:luling,
>Iovcmcnt i:,f Truck Loails
7 History of LO
7.1 period
1826 solving of
la values.
1870-1930
7.2 period
George 1047
1950s
1960s
1970s Complexity
1979
1980s Interior
1990s conic
2000s
Where do Arise?
8.1 Wide . Air
9 Trar~sportatioll
Dat,a
171 11 ~snrchouscs
.si supply i 1 m
ti,? i:lcrnnn,S j t h >iarchousc, j = 11
9.2.1 Fur~~l~~ la t iur i
r i j = numl:,cr i:,f t,o send i i j
Sorting
11 Invest ~ r ~ e v ~ t urlder
You have purchnsci:l .5i sharcs i:,f i pricc y i . i 11
Cl~rrrcnt price i pi
10
Problem
9.1 . plants. . of i th plant, = . . . . of I . . .
9.2 Decision Variables
units
through LO
taxation . stock at = 1, . . . . . of stock is
You cxpcct the l:,ricc i:,f i i:,nc scar fii:,m now will bc ri
You ]:,a- cal:,ital-gains t,ax thc rat? ,311 any t,hc t,imc i:,f the sale.
You want ti:, raise C ami:,unt crash aft,cr taxes.
You 1%)
Example: You sell shares per sharc; you ha,~:c them $30 per Vet
- -
Five invcstmcnt .-i. B. C , D.
.-i. C, and D a,~:ailal:,lc
availablc
carns 6% per year.
C;asli Flowper Ilivest,ed
of
pay in transaction costs
1.000 a t $50 bought a t sharc: cash is:
SO x 1.000 0.30 x (SO 30) x 1,000
that stock
a a t of 30% capital gains at
choices E
arc in 1993.
B is in 1994.
Cash
S1.OOO.OOOin 1993.
12.1 Dollar
Variables
.I, invcst,cd Y;
C'~I,../I~: ami:,unt invcstcd pcrii:,d = 1.
1.0GCu.~h3 1.00B 1 . i 5 D + 1.40E s.t . . l+ C:+D+ C'udhl 5 1
CIA.S/L~ B 5 0.3.1+ l . l C + l.OGC'u.~hl Cil.sI~3 l.OE < l . O l + 0.3A 1.06C'ash2
11 l:,roilucts, m raw nlatcrials
h i : a,~:ailal:,lc i .
a i j : # nlatcrial i proi:luct j needs ori:lcr ti:, lbc proi:lucc,S.
Formulat,ion
rj = i:,f pri:,,Suct j pri:,iSucc,S.
n
C qis,i j= l
12.2.1 Decision . . . .E: amount in millions
in cash in t , t 2 , 3
max + +
+ + +
13 Manufacturing
13.1 Data
units of material
units of in
13.2
13.2.1 Decision variables
amount
max
Exparlsiovi
C;olistraiilt,s
Dt: fc,rccast,ccl clcmani:l fi:n electricit,:: ::car
Et: cxisti~lg cal:,acity (in nvailablc
c,: ci:,st ti:, l:,roclucc 11\I\\' using capncity
l i t : ti:, proi:lucc 1MTV using nuclcnr cnpaci t ,~
morc nu,rlca,r
ycnri
Nuclear Inst :7cars
r,: ami:,unt ci:,al cal:,acity lint ycar
yt: nmount i:,f capncit,:: I:,rought i:,n line ycnr
u:,: tot,nl ci:,al cal:,acity ycar
zt: t,otal cnpacit,:: in :;car
~ ian t , s ti:, >icckl:: night,shift fi:,r llurscs
D , iicmancl fi:n j = 1 T
Evcry llursc works ri:,m
14 Capacity
14.1 Data and
a t t
oil) nt t
coal
cost
No than 20%
Coal plants last 20
plants 15
14.2 Decision Variables
of brought on in t.
in t.
in t.
t .
15 Scheduling
15.1 Decision variables
Hospital mnkc its
nurses, . . .
5 clays in a
hire mininl~lm nnrnbcr nurses
rj: startiqg t,hcir week i:,n cia-
Managerrlerlt
indust,ry
1978
- Clarricrs only allowc~i ti:, ircrt,ain ri:,utcs. Hcnirc airlincs iYi:,rt,h~scst. Eastern, Southwest, ctc.
- Fares ilct,cr~nincil I:,:: Clivil Acrona,utics Boaril lbascil mileage and othcr ci:,st,s (C.4B li:,ngcr
SLII)E 26 Post Dercg l~ la t i~n
anyone ,ran anywhcrc
farcs ~ic tcrminc~i I:,y (and thc markct)
17 Managerrlerlt
Huge anil fixcil cost,s
Vcry li:,m variablc ci:,st,s pcr passenger ($lO/passcngcr i:,r lcss)
cci:,nomically ci:,mpctitivc cnvironmcnt
Ncar-pcrfcct infi:,rmat,ion and ncgligil:,lc ci:,st infi,rmatii:,n
pcrishal:,lc invcnt,ory
l\lult~il~lc farcs
Goal: of
Decision Variables # nurscs j
16 Revenue
16.1 The
Deregulation in
fly such as
(CAB) on no exists)
fly,
carrier
Revenue
sunk . Strong
of
Highly
Result:
Managerrlerlt
11 11 ilcstinatii:,ns
irlasscs (for
Rc~cnucs T!, 1.j.;. ZJ
Ca1:)acitics: i = I . . T I ; C 0.i. .I = I , . I L
Expected iicnlancls: D:)
Forillulatioil
Variables
Q,,: Q-class cu~tomers me
1;,: Y-class cu~tomers i j
zr.,::c2%, +v:,Y;,
Managerrlerlt
F\'c c s t ima t ,~ t,hat RVI hns gcncrat,cil in,rrcmcntal rcvcnuc fi,r Anlcri,ran the three ycnrs ali:,nc. i:,nc-time benefit. F\'c c x p r t RM gcncrat,c lcnst millii:,n nnnually for the fi:,rcsccnl:,lc
.-is me invest the cnhanccmcnt DIV.-i?rlO me cxl:,cct t,o cnpt,urc even lnrgcr rcvcnuc
18 Revenue
18.1 Data
origins. . I hub
2 simplicity), (2-class. Ti-class . , . . . . . .
18.2 LO
18.2.1 Decision . #of accept from i to j . # of accept from to
maximize
19 Revenue
$1.4 billion in Airlines in last This is not a
t o at $500 future. continue t o in of
nn premium.
t,o
1. Define your ilccision variables clearly.
ITrritc ci:,nstraints ani:l ol:,jcctivc funct,ion.
for~ril~latiorl? fi,rmulation with a numl:,cr variaI:,lcs anil const,raint,s, anil t,hc mat,rix
sparse.
proble~ll
furlctiorls
: . S + R
sl. s2 E ,Y
f(As1 ( l h ) s ? ) 5 Xf(sl)+ (lPA)f(s2)
,f ci:,ncavc - (z) ci:,nvcx.
0 x 1 the LO
(z) dn z ci,
.5.t. 3 b
20 Messages
20.1 How formulate?
2.
What is a good LO A of A is
21.1 The general
22 Convex
f
. (z) if f
power of 23
. For all
+
min f = maxi, + Az
0x1 the
C t,j l.cjl n . t . Az 2 b
1x1 = max{s, s ] mi11 C qiqi
Ax 2 b
r.i 5 z.? " j 5 z j
>Iinimizing Picirc~sisc lincnr convex functii:,n ,ran lbc moi:lcllcil I:,y
24 power of LO
min
Idea:
5.t.
Message: LO
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6.251J / 15.081J Introduction to Mathematical ProgrammingFall 2009