Managing Software Development

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Managing Software Development

• Karl Lieberherr

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Manage a significant program from requirements to
implementation

• We wrote requirements. We wrote several
  requirement documents that were good enough.
• http//www.ccs.neu.edu/home/lieber/evergreen/speck
  er/sdg-home.html
• It is hard to get them perfect.

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Specker Derivative Game (SDG)

• About buying and selling generative, active
  participation products based on partial
  information.
• Partial information type T of CSP formula
• Generates raw material CSP formula of given
  type T
• Active participation Finish raw material.

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Other instances

• buy a course
• raw materials lectures, projects
• active participation you need to finish them
  absorb the material, apply the material.
• buy a membership in a health club
• raw materials equipment, classes
• active participation use it.

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What is needed to write good code?

• Understanding the application domain is important
  to writing good code.
• Application domain topics we encountered
• solving min-max problems
• reductions
• maximizing polynomials
• minimizing functions
• transition systems for solving MAX-CSP

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Golden nuggets of insight

• May simplify your program significantly.
• Are at a conceptual level.

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Application domain knowledge

• dozens of relations in type
• reduce to two for raw material construction!!
• symmetric formulas are the worst case

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Controlling complexity of raw materials

• Set of relations R(1,1), R(pos,length) pos of
  length literals are positive, length gt2.
• RR R(1,1), R(pos,length), length gt2
• e.g., RR (R(1,1),R(0,2),R(1,2),R(2,2), R(0,3),
  R(2,3)
• Lemma The worst raw material in this class only
  needs to use RRsimpleR(1,1), R(0,2).

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Proof

• Let s be an arbitrary RR-formula. We simplify it
  to a cnf T(S) using
• In clauses containing positive literals, drop all
  but one.
• In clauses containing only negative literals, but
  more than one, drop all except two.
• T(s) is in RRsimple and to each assignment I1 of
  T(s) corresponds an assignment I of s which
  satisfies at least as many clauses as I1 in T(s).

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Example of reduction
A B C A B !A !B !C A C B !C !A
!B !C !D

• A B C
• A B
• !A !B !C
• A C
• B !C
• !A !B !C !D

3A 2!A !B 1 B
A1,B0,C0 all sat
A1,B0,C0 5/6 sat
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R 22
¾ only

• a b c
• a b d
• a c d
• b c d

a b c a b d a c d
can satisfy all
symmetric
apply all 4! 1234 24 permutations
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Symmetrized formula
18a b c 18a b d 18a c d 18 b c d