From 4c494c5dbed5e057ac788ec6e72498b9d6e78953 Mon Sep 17 00:00:00 2001
From: David Tonhofer <ronerycoder@gluino.name>
Date: Fri, 13 Aug 2021 16:49:55 +0200
Subject: [PATCH] Add more comments

Might be useful when newcomers pick the code apart
---
 packing/rotation/sbprgeost.mzn | 47 ++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/packing/rotation/sbprgeost.mzn b/packing/rotation/sbprgeost.mzn
index c568da8..ee9d118 100644
--- a/packing/rotation/sbprgeost.mzn
+++ b/packing/rotation/sbprgeost.mzn
@@ -1,19 +1,28 @@
-int: n; % number of blocks
+% --- Parameters ---
+  
+int: n; % number of blocks (also called "shapes")
 set of int: BLOCK = 1..n;
-int: m; % number of rectangle/offsets
+   
+int: m; % number of rectangle/offsets into the 'd' array
 set of int: ROFF = 1..m;
-array[ROFF,1..4] of int: d; % defns
-array[int] of set of ROFF: shape;
+array[ROFF,1..4] of int: d; % geometries of rectangles that can be used to compose rotated shapes; 2nd dimension is one of (x,y,w,h)
+  
+array[int] of set of ROFF: shape; % array of set of index from ROFF: shapes and their rotations
+  
 int: h; % width of river
 int: maxl; % maximum length of river
-
+  
+% --- Decision variables ---
+  
 array[BLOCK] of var 0..maxl: x;
 array[BLOCK] of var 0..h: y;
-
+  
 var 0..maxl: l; % length of river used
-
+  
 solve minimize l;
-
+  
+% --------------------------
+  
 % extract the offsets and sizes
 array[ROFF,1..2] of int: rsize =
    array2d(ROFF, 1..2,
@@ -21,26 +30,26 @@ array[ROFF,1..2] of int: rsize =
 array[ROFF,1..2] of int: roff =
    array2d(ROFF, 1..2,
       [d[i,j] | i in ROFF, j in 1..2]);
-
+  
 % pack the x and y coordinates
 array[BLOCK,1..2] of var int: coord;
 constraint forall(i in BLOCK)
    (coord[i,1] = x[i] /\ coord[i,2] = y[i]);
-
+  
 % set up the "kind" constraints
 array[BLOCK] of var int: kind;
 array[BLOCK] of set of int: shapeind;
 constraint forall(i in BLOCK)(kind[i] in shapeind[i]);
-
+  
 include "geost.mzn";
 constraint geost_bb(2,
-         rsize,
-         roff,
-         shape,
-         coord,
-         kind,
+         rsize,     % given: 1st dimension: rectangle index (∈ ROFF), 2nd dimension: 1 (maps to width), 2 (maps to height)
+         roff,      % given: 1st dimension: rectangle index (∈ ROFF), 2nd dimension: 1 (maps to x), 2 (maps to y)
+         shape,     % given: array of set of index (∈ ROFF): shapes and their rotations (a bit less than 4 * card(BLOCK) in length)
+         coord,     % sought: 1st dimension: shape index (∈ BLOCK), 2nd dimension: 1 (maps to x), 2 (maps to y)
+         kind,      % sought: a mapping from shape index (∈ BLOCK) to one of the allowed (rotated) shape description for that index
          [ 0,0 ],
          [ l,h ]);
-
-
-output ["l = \(l);\nx = \(x);\ny = \(y);\nkind = \(kind);\n"];
\ No newline at end of file
+  
+  
+output ["l = \(l);\nx = \(x);\ny = \(y);\nkind = \(kind);\n"];