Steps for Two-Phase Method
The procedure of removing artificial variables is achieved in phase-I of the solution and phase-II is required to get an optimal solution. As the solution of LPP is calculated in two phases, it is known as Two-Phase Simplex Method.
Phase I - In this particular phase, the simplex method is applied to a exclusively constructed auxiliary linear programming problem leading to a final simplex table consisting a basic feasible solution to the original problem.
Step 1 - Allot a cost -1 to each artificial variable and a cost 0 to all the other variables in the objective function.
Step 2 - Make the Auxiliary LPP in which the new objective function Z* is to be maximized subject to the specified set of constraints.
Step 3 - Work out the auxiliary problem hrough simplex method until either of the following three possibilities do occur
i. Max Z* < 0 and at least one artificial vector seems in the optimum basis at a positive level (Δj ≥ 0). In this case, given problem does not have any feasible solution.
ii. Max Z* = 0 and at least one artificial vector seems in the optimum basis at a zero level. In this case one needs to proceed to phase-II.
iii. Max Z* = 0 and no one artificial vector seems in the optimum basis. In this case one also needs to proceed for phase-II.
Phase II - Now allocate the actual cost to the variables in the objective function and a zero cost to each artificial variable that seems in the basis at the zero level. This new objective function is at present maximized by simplex method subject to the given constraints.
Simplex method is practically applied to the modified simplex table achieved at the end of phase-I, until an optimum basic feasible solution has been reached. The artificial variables which are non-basic at the finish of phase-I are removed.
Worked Examples
Example 1
Max Z = 3x1 - x2
Subject to
2x1 + x2 ≥ 2
x1 + 3x2 ≤ 2
x2 ≤ 4
& x1 ≥ 0, x2 ≥ 0
Answer
Standard LPP
2x1 + x2 - s1+ a1= 2
x1 + 3x2 + s2 = 2
x2 + s3 = 4
x1 , x2 , s1, s2, s3,a1 ≥ 0
Auxiliary LPP
Max Z* = 0x1 - 0x2 + 0s1 + 0s2 + 0s3 -1a1
Phase I
It is observed that all Δj ≥ 0, Max Z* = 0 and no artificial vector seems in the basis, we move to phase II.
Phase II
Because all Δj ≥ 0, optimal basic feasible solution is achieved, Thus the solution is Max Z = 6, x1 = 2, x2 = 0
The important advantages of Inter Firm Comparison are Improvement in efficiency, Increased productivity, Reliable information, Assistance to Government, etc.
www.tutorsglobe.com offers answering questions to comparison of national income over time, assignment help - homework help in economics subject.
Theory and lecture notes of Functions all along with the key concepts of Function Notation, Function Definition, Function Evaluation, Piecewise Definitions, Piecewise Functions and Calculator and Finding Domain. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Functions.
Theory and lecture notes of Changes in Macro-Economy all along with the key concepts of changes in macro-economy, Occupational Distribution of the Labor Force. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Changes in Macro-Economy.
Opening and closing stocks cost audit program - the opening stock is not excessively large compared with the volume of production throughout the year;
Shares present the basic units of ownership of a business. Every companies issue ordinary shares. Preference shares assurance that if a dividend is paid, the preference shareholders will be permitted to the first part of it up to a maximum value.
www.tutorsglobe.com offers biophysical chemistry homework help, biophysical chemistry assignment help, online tutoring assistance, physical chemistry solutions by online qualified tutor's help.
Gravitational Motion tutorial all along with the key concepts of Law of Universal Gravitation, Kepler's Laws of Planetary Motion, Mass and Weight, Mass of the Earth, universal gravitational constant
tutorsglobe.com merits of mixed economy assignment help-homework help by online mixed economy tutors
tutorsglobe.com shape of p-orbitals assignment help-homework help by online shapes of orbitals tutors
Theory and lecture notes of LM Curve Money all along with the key concepts of lm curve, Money Demand Varies as Total Income, From Money Demand to the LM Curve. Tutorsglobe offers homework help, assignment help and tutor’s assistance on LM Curve Money.
tutorsglobe.com functions of minerals assignment help-homework help by online mineral nutrition tutors
Types and Effects of Linkages on Nature of Polymers tutorial all along with the key concepts of Types of linkages in the polymer, Cross-linkings, Bakelite is a commercially important polymer, Implications of cross-linking in polymers, More properties of polymers
tutorsglobe.com management of cash assignment help-homework help by online working capital management tutors
Theory and lecture notes of Resistive Configurations all along with the key concepts of resistors in series, kirchhoffs voltage law, resistors in parallel, potential divider and current splitting. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Resistive Configurations.
1953644
Questions Asked
3689
Tutors
1462114
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!