Assignment
3,
Logistics
Analytics
This
exercise
is
about
two
tasks
• creating
an
AMPL
model
based
on
a
rough
description
and
a
given
data
file.
• Demonstrating
the
differences
between
the
network
problems
discussed
in
class
1.
Multi
Commodities
(12Marks)
The
following
problem
is
similar
to
the
transshipment
problems
we
had
in
class,
but
is
not
using
one
but
3
products.
The
data
is
given
in
a
dat-‐file
on
blackboard
mcp.dat.
This
file
has
to
be
used
for
the
model.
The
cost
from
the
plants
to
the
DCs
(costs)
as
well
as
the
cost
from
the
DC
to
the
regions
(costr)
are
presented
in
a
3-‐dimensional
parameter.
That
is,
param
costs{PLANTS,
DCS,
PRODUCTS)
>=
0;
The
access
to
elements
is
similar
to
the
2-‐dimensional
with
costs[i,j,k].
param costs := [*,*,P1]: A B := C 6 5 D 4 7 M 6 9
The
code-‐snippet
shows
the
cost
for
product
1
from
the
plants
C,
D,
and
M
to
the
DC
A
and
B.
Otherwise,
the
following
constraints
are
given:
• Supply
per
plant
per
product
is
limited
according
to
“supply”
• Minimum
demand
per
region
is
given
in
“demand”
• All
incoming
orders
to
the
DC
are
fully
forwarded
to
the
regions
• The
DCs
have
a
capacity
• Even
though
there
is
a
capacity
for
the
supply
per
plant
and
product,
there
is
also
an
overall
max
supply
per
plant
(maxsupply)
The
overall
goal
is
to
minimize
the
cost
of
transport.
Note
that
there
are
no
fixcosts.
Hints:
Even
though
there
might
be
other
solutions,
I
am
looking
for
the
objective
function,
the
variable
and
parameter
definitions,
and
constraints
(5
in
my
solution).
Hint
2:
Objective
function
is
6150,
the
transport
quantities
for
B
(DC)
to
NY
(region)
for
product
P3
is
25,
C
to
A
for
P1
=
0,
M
to
A
for
P3
150.
Marks
are
given
for
the
declaration
of
param,
set,
var
(25%),
the
objective
function
(25%),
and
5
constraints
(each
10%
=
50%).
2.
Multi
Commodities
(8Marks)
In
class,
we
discussed
the
following
problems
• Transshipment
problem
• General
transshipment
problem
• Max-‐Flow
Problem
• Routing
Problem
• Minimal
Spanning
Tree
I
mentioned
that
all
have
lots
of
similarities
and
some
differences,
but
overall
knowing
these
helps
to
understand
and
write
new
problems.
Thus,
I
ask
you
to
create
a
short
overview
about
similarities
and
differences
of
these
5
problems.
Choose
a
good
representation
to
demonstrate
this;
i.e.
trying
to
find
a
compact
and
comprehensive
representation
of
these.
Note:
Just
copying
constraints,
obj-‐fcts,
or
data
is
not
what
I
ask.
You
have
to
explain
this
so
that
someone
not
familiar
is
understanding
its.
This
pinpointing
the
difference
is
the
key
here.
NOTE
If
you
have
further
questions
or
believe
there
is
something
missing
or
wrong,
please
write
on
the
ed-‐discussion
board
(using
the
category
assignment-‐>A3)
Don’t
post
solutions.