Presented at FOSSASIA 2018

2. Melvin Zhang
melvin@melvinzhang.net
@melvinzhangzy
theintelligentwarehouse.com
magarena.github.io

3. Optimization: shortest path
https://www.google.com.sg/maps

4. Optimization: best fit line
https://en.wikipedia.org/wiki/Least squares

5. Optimization: model with least error
https://medium.com/onfido-tech/machine-learning-101-be2e0a86c96a

6. Most optimizations problems are hard
https://xkcd.com/287/

7. Constraint Programming

8. http://www.minizinc.org/
Solver independent modelling language

9. Jake is 3 years older than Kyla and 2 years
younger than Larry. The total of their ages is
41 years. Find Jake’s age.
Demo: a word problem
https://www.singaporemath.com/v/sf tmbm.pdf

10. var int: jake_age;
var int: kyla_age;
var int: larry_age;
int: sum = 41;
constraint jake_age = kyla_age + 3;
constraint jake_age + 2 = larry_age;
constraint jake_age + kyla_age + larry_age = sum;
solve satisfy;
output [
"jake : ", show(jake_age), "n",
"kyla : ", show(kyla_age), "n",
"larry: ", show(larry_age)
];

11. Under the hood
https://wiki.onap.org/display/DW/

12. Demo: https://xkcd.com/287/

13. int: n = 6;
array[1..n] of int: price =
[215, 275, 335, 355, 420, 580];
int: total = 1505;
array[1..n] of var int: cnt;
var int: z = sum(i in 1..n) (cnt[i]);
solve minimize z;
constraint total = sum(i in 1..n) (cnt[i]*price[i])
constraint forall(i in 1..n) (cnt[i] >= 0)
output [
show(cnt)
];

14. Demo: a FOSSASIA special
F O S S
+ A S I A
---------
2 0 1 8

15. include "alldifferent.mzn";
enum letters = {F, O, S, A, I};
int: sum = 2018;
array[letters] of var 0..9: v;
constraint 1000 * v[F] + 100 * v[O] + 10 * v[S] + v[S]
+ 1000 * v[A] + 100 * v[S] + 10 * v[I] + v[A]
= sum;
constraint alldifferent(v);
solve satisfy;
output [
show(v)
];

16. Conclusion
References
A MiniZinc tutorial:
https://www.minizinc.org/downloads/doc-latest/minizinc-tute.pdf
Various MiniZinc models:
http://www.hakank.org/minizinc/