X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=moebius2.git;a=blobdiff_plain;f=energy.c;h=19f32e2fa3a0459ab94339a202b6844120b0a8b1;hp=5aa1c602b8387cd75f6c0e75437f7f63bd6f3edc;hb=32c7d2a5c5cb58ed3a8fb9fc383a31a80b01c052;hpb=21a2bd20afe0f4673494f4841a5675ca68cbd2d7

diff --git a/energy.c b/energy.c
index 5aa1c60..19f32e2 100644
--- a/energy.c
+++ b/energy.c
@@ -16,59 +16,98 @@ static void addcost(double *energy, double tweight, double tcost, int pr);
 /*---------- main energy computation, weights, etc. ----------*/
 
 typedef double CostComputation(const Vertices vertices, int section);
+typedef void PreComputation(const Vertices vertices, int section);
 
 typedef struct {
   double weight;
   CostComputation *fn;
 } CostContribution;
 
-static const CostContribution costs[]= {
+#define NPRECOMPS ((sizeof(precomps)/sizeof(precomps[0])))
+#define NCOSTS ((sizeof(costs)/sizeof(costs[0])))
 #define COST(weight, compute) { (weight),(compute) },
 
+static PreComputation *const precomps[]= {
+  compute_edge_lengths,
+  compute_vertex_areas
+};
+
+static const CostContribution costs[]= {
+
 #if XBITS==3
-#define STOP_EPSILON 1e-6;
-    COST(  3e2,   line_bending_cost)
-    COST(  1e3,   edge_length_variation_cost)
-    COST( 0.2e3,  rim_proximity_cost)
-    COST(  1e8,   noncircular_rim_cost)
+#define STOP_EPSILON 1e-6
+    COST(  3e3,   vertex_displacement_cost)
+    COST( 0.4e3,  rim_proximity_cost)
+    COST(  1e7,   edge_angle_cost)
+                  #define EDGE_ANGLE_COST_CIRCCIRCRAT (0.2/1.7)
+    COST(  1e2,   small_triangles_cost)
+    COST(  1e12,   noncircular_rim_cost)
 #endif
 
 #if XBITS==4
-#define STOP_EPSILON 1e-5;
-    COST(  3e2,   line_bending_cost)
-    COST(  3e3,   edge_length_variation_cost)
-    COST( 3.8e1,  rim_proximity_cost) // 5e1 is too much
-					 // 2.5e1 is too little
+#define STOP_EPSILON 1.2e-4
+    COST(  3e3,   vertex_displacement_cost)
+    COST( 0.2e3,  rim_proximity_cost)
+//    COST(  1e6,   edge_angle_cost)
+                  #define EDGE_ANGLE_COST_CIRCCIRCRAT (0.5/1.7)
+//    COST(  1e1,   small_triangles_cost)
+    COST(  1e12,   noncircular_rim_cost)
+#endif
+
+#if XBITS==5
+#define STOP_EPSILON 1.2e-4
+    COST(  3e7,   line_bending_cost)
+    COST( 10e2,   prop_edge_length_variation_cost)
+    COST( 9.0e3,  rim_proximity_cost) // 5e1 is too much
+				      // 2.5e1 is too little
     // 0.2e1 grows compared to previous ?
     // 0.6e0 shrinks compared to previous ?
-    COST(  1e12,   noncircular_rim_cost)
+
+//    COST(  1e12,   edge_angle_cost)
+                  #define EDGE_ANGLE_COST_CIRCCIRCRAT (0.5/1.3)
+    COST(  1e18,   noncircular_rim_cost)
 #endif
+
+#if XBITS>=6 /* nonsense follows but never mind */
+#define STOP_EPSILON 1e-6
+    COST(  3e5,   line_bending_cost)
+    COST( 10e2,   edge_length_variation_cost)
+    COST( 9.0e1,  rim_proximity_cost) // 5e1 is too much
+				      // 2.5e1 is too little
+    // 0.2e1 grows compared to previous ?
+    // 0.6e0 shrinks compared to previous ?
+
+    COST(  1e12,   edge_angle_cost)
+                  #define EDGE_ANGLE_COST_CIRCCIRCRAT (0.5/1.3)
+    COST(  1e18,   noncircular_rim_cost)
+#endif
+
 };
 
-#define NCOSTS ((sizeof(costs)/sizeof(costs[0])))
+const double edge_angle_cost_circcircrat= EDGE_ANGLE_COST_CIRCCIRCRAT;
 
 void energy_init(void) {
   stop_epsilon= STOP_EPSILON;
 }
 
+/*---------- energy computation machinery ----------*/
+
 void compute_energy_separately(const struct Vertices *vs,
 			 int section, void *energies_v, void *totals_v) {
   double *energies= energies_v;
   int ci;
-    
-  compute_edge_lengths(vs->a, section);
-  compute_vertex_areas(vs->a, section);
-
+  
+  for (ci=0; ci<NPRECOMPS; ci++) {
+    precomps[ci](vs->a, section);
+    inparallel_barrier();
+  }
   for (ci=0; ci<NCOSTS; ci++)
     energies[ci]= costs[ci].fn(vs->a, section);
 }
 
-/*---------- energy computation machinery ----------*/
-
 void compute_energy_combine(const struct Vertices *vertices,
 			 int section, void *energies_v, void *totals_v) {
   int ci;
-  
   double *energies= energies_v;
   double *totals= totals_v;
 
@@ -86,6 +125,9 @@ double compute_energy(const struct Vertices *vs) {
 
   if (printing) printf("%15lld c>e |", evaluations);
 
+  for (ci=0; ci<NCOSTS; ci++)
+    totals[ci]= 0;
+
   inparallel(vs,
 	     compute_energy_separately,
 	     compute_energy_combine,
@@ -93,7 +135,6 @@ double compute_energy(const struct Vertices *vs) {
 	     totals);
 
   energy= 0;
-
   for (ci=0; ci<NCOSTS; ci++)
     addcost(&energy, costs[ci].weight, totals[ci], printing);
 
@@ -138,7 +179,7 @@ static void addcost(double *energy, double tweight, double tcost, int pr) {
 void compute_edge_lengths(const Vertices vertices, int section) {
   int v1,e,v2;
 
-  FOR_EDGE(v1,e,v2,OUTER)
+  FOR_EDGE(v1,e,v2, OUTER)
     edge_lengths[v1][e]= hypotD(vertices[v1],vertices[v2]);
 }
 
@@ -146,7 +187,7 @@ void compute_vertex_areas(const Vertices vertices, int section) {
   int v0,v1,v2, e1,e2;
 //  int k;
 
-  FOR_VERTEX(v0,OUTER) {
+  FOR_VERTEX(v0, OUTER) {
     double total= 0.0, edges_total=0;
     int count= 0;
 
@@ -172,7 +213,47 @@ void compute_vertex_areas(const Vertices vertices, int section) {
   }
 }
 
-/*---------- Edgewise vertex displacement ----------*/
+/*---------- combined vertex displacement ----------*/
+
+  /*
+   *   At vertex Q considering edge direction e to R
+   *   and corresponding opposite edge to P.
+   *
+   *   Let  R' = Q + PQ
+   *        D  = R' - R
+   *                                                             delta
+   *              [       -1                                    ]
+   *   cost    =  [ lambda  . ( D . PQ/|PQ| ) + | D x PQ/|PQ| | ]
+   *       Q,e    [ ------------------------------------------- ]
+   *              [                      |PQ|                   ]
+   */
+
+double vertex_displacement_cost(const Vertices vertices, int section) {
+  const double inv_lambda= 1.0/1; //2;
+  const double delta= 4;
+  const double pqlen2_epsilon= 1e-12;
+
+  int pi,e,qi,ri, k;
+  double pq[D3], d[D3], ddot, dcross[D3];
+  double total_cost= 0;
+
+  FOR_EDGE(qi,e,ri, OUTER) {
+    pi= EDGE_END2(qi,(e+3)%V6); if (pi<0) continue;
+
+    K pq[k]= -vertices[pi][k] + vertices[qi][k];
+    K d[k]= vertices[qi][k] + pq[k] - vertices[ri][k];
+    ddot= dotprod(d,pq);
+    xprod(dcross, d,pq);
+    double pqlen2= magnD2(pq);
+    double cost_basis= inv_lambda * ddot + magnD(dcross);
+    double cost= pow(cost_basis / (pqlen2 + pqlen2_epsilon), delta);
+
+    total_cost += cost;
+  }
+  return total_cost;
+}
+
+/*---------- at-vertex edge angles ----------*/
 
   /*
    * Definition:
@@ -210,7 +291,7 @@ void compute_vertex_areas(const Vertices vertices, int section) {
 
 double line_bending_cost(const Vertices vertices, int section) {
   static const double axb_epsilon= 1e-6;
-  static const double exponent_r= 3;
+  static const double exponent_r= 4;
 
   int pi,e,qi,ri, k;
   double  a[D3], b[D3], axb[D3];
@@ -219,6 +300,8 @@ double line_bending_cost(const Vertices vertices, int section) {
   FOR_EDGE(qi,e,ri, OUTER) {
     pi= EDGE_END2(qi,(e+3)%V6); if (pi<0) continue;
 
+//if (!(qi&XMASK)) fprintf(stderr,"%02x-%02x-%02x (%d)\n",pi,qi,ri,e);
+
     K a[k]= -vertices[pi][k] + vertices[qi][k];
     K b[k]= -vertices[qi][k] + vertices[ri][k];
 
@@ -227,9 +310,6 @@ double line_bending_cost(const Vertices vertices, int section) {
     double delta= atan2(magnD(axb) + axb_epsilon, dotprod(a,b));
     double cost= pow(delta,exponent_r);
 
-    if (!e && !(qi & ~XMASK))
-      cost *= 10;
-
     total_cost += cost;
   }
   return total_cost;
@@ -258,6 +338,34 @@ double edge_length_variation_cost(const Vertices vertices, int section) {
   return cost;
 }
 
+/*---------- proportional edge length variation ----------*/
+
+  /*
+   * Definition:
+   *
+   *    See the diagram above.
+   *                                r
+   *       cost    = ( |PQ| - |QR| )
+   *           Q,e
+   */
+
+double prop_edge_length_variation_cost(const Vertices vertices, int section) {
+  const double num_epsilon= 1e-6;
+
+  double cost= 0, exponent_r= 2;
+  int q, e,r, eback;
+
+  FOR_EDGE(q,e,r, OUTER) {
+    eback= edge_reverse(q,e);
+    double le= edge_lengths[q][e];
+    double leback= edge_lengths[q][eback];
+    double diff= le - leback;
+    double num= MIN(le, leback);
+    cost += pow(diff / (num + num_epsilon), exponent_r);
+  }
+  return cost;
+}
+
 /*---------- rim proximity cost ----------*/
 
 static void find_nearest_oncircle(double oncircle[D3], const double p[D3]) {
@@ -305,3 +413,128 @@ double noncircular_rim_cost(const Vertices vertices, int section) {
   }
   return cost;
 }
+
+/*---------- overly sharp edge cost ----------*/
+
+  /*
+   *
+   *   	            Q `-_
+   *              / |    `-_		               P'Q' ------ S'
+   *             /  |       `-.		             _,' `.       .
+   *            /   |           S	          _,'     :      .
+   *           /    |      _,-'                _,'        :r    .r
+   *          /     |  _,-'		   R' '           `.   .
+   *         /    , P '			       ` .   r     :  .
+   *        /  ,-'			            `  .   : 
+   *       /,-'				                 ` C'
+   *      /'
+   *   	 R
+   *
+   *
+   *
+   *  Let delta =  angle between two triangles' normals
+   *
+   *  Giving energy contribution:
+   *
+   *                                   2
+   *    E             =  F   .  delta
+   *     vd, edge PQ      vd
+   */
+
+double edge_angle_cost(const Vertices vertices, int section) {
+  double pq1[D3], rp[D3], ps[D3], rp_2d[D3], ps_2d[D3], rs_2d[D3];
+  double a,b,c,s,r;
+  const double minradius_base= 0.2;
+
+  int pi,e,qi,ri,si, k;
+//  double our_epsilon=1e-6;
+  double total_cost= 0;
+
+  FOR_EDGE(pi,e,qi, OUTER) {
+//    if (!(RIM_VERTEX_P(pi) || RIM_VERTEX_P(qi))) continue;
+
+    si= EDGE_END2(pi,(e+V6-1)%V6);  if (si<0) continue;
+    ri= EDGE_END2(pi,(e   +1)%V6);  if (ri<0) continue;
+
+    K {
+      pq1[k]= -vertices[pi][k] + vertices[qi][k];
+      rp[k]=  -vertices[ri][k] + vertices[pi][k];
+      ps[k]=  -vertices[pi][k] + vertices[si][k];
+    }
+
+    normalise(pq1,1,1e-6);
+    xprod(rp_2d, rp,pq1); /* projects RP into plane normal to PQ */
+    xprod(ps_2d, ps,pq1); /* likewise PS */
+    K rs_2d[k]= rp_2d[k] + ps_2d[k];
+    /* radius of circumcircle of R'P'S' from Wikipedia
+     * `Circumscribed circle' */
+    a= magnD(rp_2d);
+    b= magnD(ps_2d);
+    c= magnD(rs_2d);
+    s= 0.5*(a+b+c);
+    r= a*b*c / sqrt((a+b+c)*(a-b+c)*(b-c+a)*(c-a+b) + 1e-6);
+
+    double minradius= minradius_base + edge_angle_cost_circcircrat*(a+b);
+    double deficit= minradius - r;
+    if (deficit < 0) continue;
+    double cost= deficit*deficit;
+
+    total_cost += cost;
+  }
+
+  return total_cost;
+}
+
+/*---------- small triangles cost ----------*/
+
+  /*
+   *
+   *   	            Q `-_
+   *              / |    `-_
+   *             /  |       `-.
+   *            /   |           S
+   *           /    |      _,-'
+   *          /     |  _,-'
+   *         /    , P '
+   *        /  ,-'
+   *       /,-'
+   *      /'
+   *   	 R
+   *
+   *  Let delta =  angle between two triangles' normals
+   *
+   *  Giving energy contribution:
+   *
+   *                                   2
+   *    E             =  F   .  delta
+   *     vd, edge PQ      vd
+   */
+
+double small_triangles_cost(const Vertices vertices, int section) {
+  double pq[D3], ps[D3];
+  double x[D3];
+  int pi,e,qi,si, k;
+//  double our_epsilon=1e-6;
+  double total_cost= 0;
+
+  FOR_EDGE(pi,e,qi, OUTER) {
+//    if (!(RIM_VERTEX_P(pi) || RIM_VERTEX_P(qi))) continue;
+
+    si= EDGE_END2(pi,(e+V6-1)%V6);  if (si<0) continue;
+
+    K {
+      pq[k]= vertices[qi][k] - vertices[pi][k];
+      ps[k]= vertices[si][k] - vertices[pi][k];
+    }
+    xprod(x, pq,ps);
+
+    double cost= 1/(magnD2(x) + 0.01);
+
+//double cost= pow(magnD(spqxpqr), 3);
+//assert(dot>=-1 && dot <=1);
+//double cost= 1-dot;
+    total_cost += cost;
+  }
+
+  return total_cost;
+}