Phan Tich Do Nhay

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Phn tch nhy

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  • Bi 6 Phn tch nhyWhat happens to the decision If the inputs change

  • Nhc li Bi ton qui hoch tuyn tnhTm cc phn t x1, x2, , xn sao choHm mc tiuZ = c1x1 + c2x2 + + cnxn min / maxiu kin rng buc AX = B nh saua11x1+ a12x2+a1nxn= b1a21x1+ a22x2+a2nxn= b2am1x1+ am2x2+amnxn= bmiu kin kh thi:xi 0 v bi 0 vi (i = 1..n)

  • Bi ton: ErosLibNh hng G rn EFC cn xc nh phng n ch bin 4 loi thc phm hiu qu nht da trn cc s liu sauMi ngy EFC c th mua ti a 4,600 v nguyn liu v c th huy ng ti a 5,000 gi L. Theo hp ng k, EFC phi giao ng 950 v thc phm cc loi trong t nht 400 v c gTm phng n ch bin t hiu qu nht

  • Nhim v 1 Lp m hnhTm X1, X2, X3, X4 tng ng l lng g vin, cnh g, i g, v c g ca hng cn ch bin

    Mc tiu: doanh thu Z=4x1+6x2+7x3+8x4 maxCc rng buc:2x1+3x2+4x3+7x4 4600 ; gii hn nguyn liu 3x1+4x2+5x3+6x4 5000 ; gii hn gi cngx1 + x2 + x3 + x4 = 950 ; theo hp ng x4 400 ; yu cu c gx1, x2, x3, x4 0 ; rng buc t nhin

  • Gii bi ton quy hoch tuyn tnhPhng php? thn hnhExcelHow to

  • Phng n ti u

  • Cc li THNG xy ra khi dng SolverQun chn mc Assume Non-Negativity

    Qun chn mc Assume Linear Model

    Cho rng ai cng bit quy hoch tuyn tnh

    Ghi nh Kim tra cc mc trn trong phn ty chn Solver Options trc khi gii

  • Li gii, ngha kinh t li gii Answer Report

  • Vn ?M hnh c n khng?

    Ri ro th trng!!!Nhu cu gi bn ?Gi Chi ph ngun lc ??Gi Lng cc ngun lc kh dng ??? Cnh tranh Sn phm mi ????M hnh??Que sera, sera !!

  • Vn ?Cu hi ln: Bng cch no/ khi no ta bit c phng n hin ti vn cn ti u khi c thay i m khng cn phi gii li bi ton?

    Thay i phng n c n gin khng? iu hnh sn xut: b tr thit b, lao ng Thu mua, cung ng nguyn liu v thnh phm

  • Bi ton LP Sensitivity AnalysisPhn tch hu ti u

    Phn tch nhy l vic nghin cu s nh hng n phng n ti u khi thay i

    Cc h s ca hm mc tiu (O.F.C.)hay Cc gi tr rng buc R.H.S.

  • How We Do This? Bo co Sensitivity report

  • Gi nh bt u

    Bin quyt nh khng nguyn

    Bi ton khng suy binSuy bin l g ? nm th hai, hc k 1

  • Case 1: thay i h s cc n c bn trong hm mc tiuHi, ngoi ch gi cnh g tng thm $0,50. Vy tng sn lng cnh g s c li hn, phi khng?Z = 4x1 + 6x2 + 7x3 + 8x4 max6,5?X = [0, 400, 150, 400]

  • Phm vi iu chnh cho phpGi tr Allowable Increase v Allowable Decrease trong bng Adjustable Cells cho bit phm vi m trong cc h s ca hm mc tiu c th thay i m khng thay i phng n ti u (n c bn trong hm mc tiu)

  • Cch lm allowable range Sensitivity reportCn c sensitivity report

    Bc 1: Kim tra gi tr thay i ca h s cc n c bn c nm trong phm vi cho php allowable range hay khng?Nu ng, th PA ti u khng i sang bc 2. Nu sai, th b qua bc 2 v chuyn sang phn sau

    Bc 2: Tnh li doanh thu mi.

  • Case 1: p nBc 1: Gi cnh g tng +0,5 < 0,666666667 l trong phm vi cho php PA ti u khng i, chuyn sang bc 2Bc 2: Tnh li doanh thu theo gi mi:Doanh thu tng thm = 0.5x2=0.5*400=$200 Tng doanh thu = 6650+200= $6850 Kt lun: If What

  • Tho lun nhm: 4 pht!Cho p n ca 2 trng hp sau.Bi ton A Gi s gi tht g vin tng thm $0,60. Phng n ti u mi l g v doanh thu thay i ra sau? Bi ton B Gi s gi i g gim $0,60. Phng n ti u mi l g v doanh thu thay i ra sau? Th k ghi li tt c cc kin ca thnh vin

  • p nBi ton A Bc 1: Gii hn ca x1 l 1 Gi tng 0,6 trong gii hn cho php. PA ti u khng i v Bc 2: Doanh thu thay i 0*0.6=0 =Bi ton BBc 1: Gii hn ca x3 l 0,5 gi gim $0,6 qu gii hnBc 2: b qua Cc nhm cho nh gi v hng thay iHow to

  • Case 2: thay i h s cc n khng c bn trong hm mc tiuHi, g vin tng gi v khng c ai lm. Nhng khng bit tng bao nhiu th mi c liTo be or not to be?Z = 4x1 + 6x2 + 7x3 + 8x4 maxX = [0, 400, 150, 400]

  • Cch lm reduced costNu reduced cost ca n khng c bn xi l ri tc l nu h s n tng thm ri th s c phng n ti u mi cha n .

    p n: V reduced cost ca g vin l 1 ch cn tng gi g vin thm t nht l $1 th c th a g vin vo ch bin.

  • Tho lun nhm: Whos bestBi ton C iu g s xy ra nu tng gi g vin ln ng $5.

    p n: Gi g vin mi l $5 tng thm ng $1, ta s nhn c phng n mi bng cch xoay n thnh c bn c nhiu PA ti u.How to

  • Tho lun nhm: Whos bestBi ton D Nhn xt g v reduced cost ca n c bn? Gii thch!

    p n. Reduced costs ca bi ton cc i l s khng dng. n c bn sn phm ang c sn xut th reduced cost l 0.

  • Case 3: Thay i ti nguyn (RHS)Hi!! Do dch cm nn VISSAN ch c th cp 4,499 thay v 4,600. PA ca ta c phi thay i g khng?2x1 + 3x2 + 4x3 + 7x4 46004499?

  • Cch lmBc 1: Kim tra gi tr thay i ca R.H.S. ca rng buc c nm trong allowable range hay khng?Nu ng, th cc n c bn ca PA ti u khng i hy chuyn sang bc 2. Nu sai, th b qua bc 2 v chuyn sang phn sau

    Bc 2: Dng gi m shadow price ca rng buc quyt nh s thay i ca gi tr ti u ca mc tiu.

  • Gi m shadow PriceGi m ca rng buc i l gi tr tng thm ca hm mc tiu khi RHS tng ln 1 n v

    Lu : gi m rng buc i CH C hiu lc bn trong phm vi RHS ca rng buc th I

  • Case 2 p nBc 1: Cung nguyn liu gim 101 (4,6004,499) < gii hn gim (150), nn cc n c bn khng i. (Tuy nhin gi tr ca chng s thay i v RHS thay i) Bc 2: Gi m ca rng buc nguyn liu l 1. Vy gi tr hm mc tiu = 6650 1*101=6549.

  • Tho lun nhm: Whos bestBi ton E: hm mc tiu s thay i bao nhiu nu gi cng huy ng l 4800? V nu l 4700?Bi ton F: Cho nhn xt v gi m i vi rng buc ? V vi rng buc =?

    Bi ton G: Nhn tin bn thch mn g no nht?

  • p n Bi ton EBc 1: Gi cng mi 4800 gim 200 trong phm vi cho php (250) n c bn khng iBc 2: gi m ca rng buc gi cng l 0, hm mc tiu thay i 0 200 = 0. Ti sao? Nu l 4700, tc l gim 300 ngoi phm vi cho php (250) . Hy xem kin ca nhm v trng hp ny?

  • p n Bi ton F Rng buc trong bi ton cc i lun lun c gi m khng dng. V trc gic, nu RHS tng tc l tng mc khng ch ca vng kh thi cao hn khng th hiu qu c !!!.Ta khng th kt lun g v du ca rng buc =. N c th dng, m, hay bng 0. Bi ton G ???? hy chng minh

  • Case 4: mua/ thu gia cng ngoiHi, Metro c th giao thm nguyn liu vi gi cao hn. Liu c th chp nhn gi tng bao nhiu?2x1 + 3x2 + 4x3 + 7x4 4600?Deal or No Deal?

  • Hng dnMi ngun lc thay i trong phm vi nht nh. Ta c th dng gi m xc nh s thay i trong mc tiu khi ngun lc thay i. Gi m nguyn liu l 1 doanh thu tng +$1 khi NL tng +1 v ha vn hoc c li th khng nn tr hn $1/ v NL tng thmGi m lao ng l 0 doanh thu s khng tng. Ta ni m hnh mi khng c ngha thc t

  • Tho lun nhmBi ton H . Gi s gi nguyn liu hin l $5. Metro ngh vi bn mc gi tng thm l $0.50 cho mi nguyn liu cung cp thm. Bn c nn chp nhn khng. Gi ha vn l g?

    Bi ton I . Tng t cho chi lao ng

  • p nBi ton H . Gi s Eros c th mua thm 1 n v vi gi nh c l $5, th doanh thu tng $1 v gi m l 1. Nh vy Eros c th tr ti a 5+1=6 v doanh thu tng 1 1=0 ha vn. Gi Eros c th tr cao nht l 6. V 5,5 < 6, giao dch c th chp nhn.

    Bi ton I . Gi m y l 0. Eros cha khai thc ht s gi cng tim nng. Tng thm lao ng l khng c ngha. Khng nn chi.

  • The End

    In all LP models the coefficients of the objective function and the constraints are supplied as input data or as parameters to the model. The optimal solution obtained by the simplex method is based on the values of these coefficients. In practice the values of these coefficients are seldom known with absolute certainty, because many of them are functions of some uncontrollable parameters. For instance, future demands, the cost of raw materials, or the cost of energy resources cannot be predicted with complete accuracy before the problem is solved. Hence the solution of a practical problem is not complete with the mere determination of the optimal solution. Each variation in the values of the data coefficients changes the LP problem, which may in turn affect the optimal solution found earlier. In order to develop an overall strategy to meet the various contingencies, one has to study how the optimal solution will change with changes in the input (data) coefficients. This is known as sensitivity analysis or post-optimality analysis.(Ravindran, Phillips and Solberg 1987)

    Tm cc phn t x1, x2, , xn sao choHm mc tiu (objective function) Z = c1x1 + c2x2 + + cnxn min (hoc max)iu kin rng buc (constraint) AX=B nh saua11x1+ a12x2+a1nxn= b1a21x1+ a22x2+a2nxn= b2am1x1+ am2x2+amnxn= bmiu kin kh thi (feasibility) ci 0 v bi 0 vi (i = 1..n)Problem Data: See dessertbeauty.comJessica sells four types of lip gloss. The resources needed to produce one unit of each are known.Exactly 950 total units must be produced. Customers demand that at least 400 units of product 4 be produced. Formulate an LP to maximize profit. Raw Materials Available