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Coding

Protocol

  • Create modules. Name the modules properly.
  • Each of your module should contain a README.md.
  • The module should be documented properly.
  • Log everything :-)

Representation

"A => B" can be represented as node "A" with a directed edge to node "B". A graph can be represented as a dictionary.

graph = {
"A": ["B", "C", ('or', ["E", "F"])],
"B": ["D"]
}

Variable notations

days = []
Set of working days.

periods(d) = [i + 1 for i in range(8)]
start from 1 (not 0)
the above code says that there are 8 periods in day "d".

teachers = []
Teacher names, or unique id's

subjects = []
Subject names, or unique id's

groups = []
Group names, or unique id's

(t, s, g, n)
Represents a lesson to be scheduled.
teacher "t" teaches subject "s" to group for n'th time in a week

duration(t, s, g, n) = k
"k" is an integer, number of periods of the lesson

lessons_teacher(t) = [(t', s, g, n) where t' = t] lessons for a given teacher "t"

lessons_group(g) = [(t, s, g', n) where g' = g] lessons for a group "g"

Basic Variables

x'(t, s, g, n, d, p)
represents that lesson (t, s, g, n) begins in day d and period p
p should be valid periods
Constraints:
min(periods(d)) <= p <= max(periods(d)) - durations(t, s, g, n) + 1

Implied Variables

x(t, s, g, n, d, p)
Formed for each lesson (t, s, g, n), each working day d and each working period p
Says that the lesson (t, s, g, n) is given in day d period p
Note the difference between x'(t, s, g, n, d, p)
See the implications and constraints in page 7

x(t, s, g, n, d)
Formed for each lesson (t, s, g, n) and each working day.
Represents that (t, s, g, n) is held in day d

x(t, d, p)
Formed for each teacher t, working day d and working period p
Represents that teacher t gives some lesson in day d and period p

x(g, d, p)
Formed for each group g, working day d and working period p
Represents that group g takes some lesson in day d and period p

x(t, d)
Formed for each teacher t and working day d
teacher t teaches during day d

x(t, p)
Formed for each teacher t and working period p
Represents that teacher t gives lessons in period p
Read page 8(end) and 9(begining) to learn why this is needed
I have a doubt in this, if any one understands, please ping me!

x(g, p) and x(g, d) can be used if required, but who cares about the students anyways :-P

Idle periods

Free in those periods but not before and after.

i(k, t, d, p)
Formed for every t, d, p and valid k
Represents that teacher t is free in day d starting from period d for k periods.

i(k, t, d)
Formed for every t, d, and valid k
Represents that teacher t is free for k periods in day d.

i(k, t)
Formed for every t and valid k
Represents that teacher t is free for k periods.

i(t, d, p)
Formed for every t, d, p
Represents that teacher t in idle in day d from period p