/*
* Vertices in strip are numbered as follows:
*
- * ___ X-2 ___ X-1 ___ 0 ___ 1 ___ 2 ___ 3 ___ 4 __
- * Y-1 Y-1 0 0 0 0 0
- * / \ / \ / \ / \ / \ / \ / \
- * / \ / \ / \ / \ / \ / \ / \
- * X-3 ___ X-2 ___ X-1 ___ 0 ___ 1 ___ 2 ___ 3 ___ 4
- * Y-2 Y-2 Y-2 1 1 1 1 1
- * \ / \ / \ / \ / \ / \ / \ /
- * \ / \ / \ / \ / \ / \ / \ /
- * ___ X-3 ___ X-2 ___ X-1 ___ 0 ___ 1 ___ 2 ___ 3 __
- * Y-3 Y-3 Y-3 2 2 2 2
- *
- * . . . . . . . . . . . . . . .
- *
- * X-4 ___ X-3 ___ X-2 ___ X-1 ___ 0 ___ 1 ___ 2 ___ 3
- * 1 1 1 1 Y-2 Y-2 Y-2 Y-2
- * \ / \ / \ / \ / \ / \ / \ /
- * \ / \ / \ / \ / \ / \ / \ /
- * ___ X-4 ___ X-3 ___ X-2 ___ X-1 ___ 0 ___ 1 ___ 2 __
- * 0 0 0 0 Y-1 Y-1 Y-1
+ * :axis of symmetry
+ * | :
+ * | :
+ * ___ X-2 ___ X-1 ___| 0 ___ 1 ___ 2 ___ 3 ___ 4 __
+ * Y-1 Y-1 |0: 0 0 0 0
+ * / \ / \ / :\ / \ / \ / \ / \
+ * / \ / \ /| : \ / \ / \ / \ / \
+ * X-3 ___ X-2 ___ X-1|___ 0 ___ 1 ___ 2 ___ 3 ___ 4
+ * Y-2 Y-2 Y-2| : 1 1 1 1 1
+ * \ / \ / \| : / \ / \ / \ / \ /
+ * \ / \ / \ :/ \ / \ / \ / \ /
+ * ___ X-2 ___ X-1 ___| 0 ___ 1 ___ 2 ___ 3 __ 4 ___
+ * Y-3 Y-3 |2: 2 2 2 2
+ * / \ / \ / :\ / \ / \ / \ / \
+ * / \ / \ /| : \ / \ / \ / \ / \
+ * X-3 ___ X-2 ___ X-1|___ 0 ___ 1 ___ 2 ___ 3 ___ 4
+ * Y-4 Y-4 Y-4| : 3 3 3 3 3
+ * | :
+ * . . . . .| :. . . . . . . . . .
+ * | :
+ * ___ X-2 ___ X-1 ___| 0 ___ 1 ___ 2 ___ 3 ___ 4 ___
+ * 2 2 |Y-3 Y-3 Y-3 Y-3 Y-3
+ * / \ / \ / :\ / \ / \ / \ / \
+ * / \ / \ /| : \ / \ / \ / \ / \
+ * __ X-2 ___ X-1|___ 0 ___ 1 ___ 2 ___ 3 ___ 3 ___ 4
+ * 1 1 | : Y-2 Y-2 Y-2 Y-2 Y-2 Y-2
+ * / \ / \ / \| : / \ / \ / \ / \ /
+ * / \ / \ / \ :/ \ / \ / \ / \ /
+ * -3 ___ X-2 ___ X-1 ___| 0 ___ 1 ___ 2 ___ 3 ___ 4 ___
+ * 0 0 0 |Y-1 Y-1 Y-1 Y-1 Y-1
+ * | :
+ * | :
+ * |
+ * ^ join, where there is
+ * a discontinuity in numbering
*
* Node x,y for
- * 0 <= x < X x = distance along
- * 0 <= y < Y y = distance across
+ * 0 <= x < X = 2^XBITS x = distance along
+ * 0 <= y < Y = 2^YBITS-1 y = distance across
*
* Vertices are in reading order from diagram above ie x varies fastest.
*
- * Y must be even. The actual location opposite (0,0) is (X-(Y-1)/2,0),
- * and likewise opposite (0,Y-1) is ((Y-1)/2,0).
+ * Note that though presentation above is equilateral triangles, this
+ * is not the case. It's actually a square lattice with half of the
+ * diagonals added. We can't straighten it out because at the join
+ * the diagonals point the other way!
*
* We label edges as follows:
*
- * \0 /1
- * \ /
- * ___ 0 __
- * 2 1 3
- * / \
- * 4/ 5\
- *
- * (This numbering permits the order-4 nodes at the strip's edge
- * to have a contiguous edge numbering 2..5 or 0..3.)
+ * \2 /1
+ * \ /
+ * ___ 0 __
+ * 3 1 0
+ * / \
+ * 4/ 5\
*
- * When we iterate over edges, we iterate first over vertices and then
- * over edges 0 to 2, disregarding edges 3 to 5.
+ * vertex number: 0000 | y | x
+ * (YBITS) XBITS
*/
#ifndef MGRAPH_H
#include "common.h"
-#define XBITS 4
-#define X (1<<XBITS)
-#define YBITS 4
-#define Y (1<<YBITS)
+#ifndef DEFSZ /* DEFSZ may be (Y/2-1)*10 + XBITS ie Y is 2*<tens>+1 */
+#define XBITS 3
+#define YBITS 3
+#define Y ((1<<YBITS) - 1)
+#define YMASK (Y << YSHIFT)
+#else
+#define XBITS (DEFSZ % 10)
+#define Y ((DEFSZ / 10)*2+1)
+#endif
-/* vertex number: 0000 | y | x
- * YBITS XBITS
- */
+#define X (1<<XBITS)
#define N (X*Y)
#define XMASK (X-1)
#define YSHIFT XBITS
#define Y1 (1 << YSHIFT)
-#define YMASK ((Y-1) << YSHIFT)
#define V6 6
+#define V3 3
-#define FOR_VERTEX(v) \
- for ((v)=0; (v)<N; (v)++)
-#define VE_MIN(v) ((v) & YMASK ? 0 : 2)
-#define VE_MAX(v) (~(v) & YMASK ? V6 : 4)
+/* Loop constructors are macros of the form
+ * LOOP(v,zero,n, precomp)
+ * which work much like this one:
+ */
+#define INNER(v,zero,n, precomp) \
+ for ((v)=(zero); precomp, (v)<(n); (v)++)
+
+#define FOR_VERTEX(v,loop) \
+ loop ((v), 0, N, NOTHING)
-#define FOR_VPEDGE(v,e) \
- for ((e)=VE_MIN(v); (e)<VE_MAX(v); (e)++)
+#define FOR_VPEDGE(e) \
+ for ((e)=0; (e)<V6; (e)++)
-extern int edge_end2(unsigned v1, int e);
+int edge_end2(unsigned v1, int e);
#define EDGE_END2 edge_end2
+/* given v1,e s.t. v2==EDGE_END2(v1,e) >= 0,
+ * returns eprime s.t. v1==EDGE_END2(v2,eprime) */
+int edge_reverse(int v1, int e);
+
+#define EDGE_OPPOSITE(e) (((e)+V3) % V6)
+
+#define RIM_VERTEX_P(v) (((v) & ~XMASK) == 0 || ((v) & ~XMASK) == (Y-1)*Y1)
+
#define FOR_VEDGE_X(v1,e,v2,init,otherwise) \
- FOR_VPEDGE((v1),(e)) \
+ FOR_VPEDGE((e)) \
if (((v2)= EDGE_END2((v1),(e)), \
(init), \
(v2)) < 0) { otherwise; } else
#define FOR_VEDGE(v1,e,v2) \
FOR_VEDGE_X(v1,e,v2,NOTHING,NOTHING)
-#define FOR_EDGE(v1,e,v2) \
- FOR_VERTEX((v1)) \
+#define FOR_EDGE(v1,e,v2, loop) \
+ FOR_VERTEX((v1), loop) \
FOR_VEDGE((v1),(e),(v2))
-#define FOR_COORD(k) \
- for ((k)=0; (k)<D3; (k)++)
-
-#define K FOR_COORD(k)
+#define FOR_RIM_VERTEX(vy,vx,v, loop) \
+ for ((vy)=0; (vy)<Y; (vy)+=Y-1) \
+ loop ((vx), 0, X, (v)= (vy)<<YSHIFT | (vx))
-#define FOR_RIM_VERTEX(vy,vx,v) \
- for ((vy)=0; (vy)<Y; (vy)+=Y-1) \
- for ((vx)=0; (v)= (vy)<<YSHIFT | (vx), (vx)<X; (vx)++)
+int vertices_span_join_p(int v0, int v1);
typedef double Vertices[N][D3];
+struct Vertices { Vertices a; };
#endif /*MGRAPH_H*/
~ian / moebius2.git / blobdiff