X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=moebius2.git;a=blobdiff_plain;f=energy.c;h=2bbf0492a5a41312d6819907995857bce9d1e180;hp=78b8f31ff44be4942efb40cb91f61d21718217b2;hb=7968bc4aca3306473e7ab0a55d4bdc721a3eacd5;hpb=e6ff377c3c846274fa3d7d98e83512d5e4226f56

diff --git a/energy.c b/energy.c
index 78b8f31..2bbf049 100644
--- a/energy.c
+++ b/energy.c
@@ -6,41 +6,31 @@
 #include "minimise.h"
 #include "mgraph.h"
 
-#include <gsl/gsl_errno.h>
-#include <gsl/gsl_multimin.h>
+double vertex_areas[N], vertex_mean_edge_lengths[N], edge_lengths[N][V6];
 
-#include <signal.h>
-#include <sys/time.h>
-
-static const char *input_file, *output_file;
-static char *output_file_tmp;
-
-static void compute_vertex_areas(const Vertices vertices, double areas[N]);
 static double best_energy= DBL_MAX;
 
-enum printing_instance { pr_cost, pr_size, pr__max };
-
 static void addcost(double *energy, double tweight, double tcost, int pr);
 #define COST(weight, compute) addcost(&energy, (weight), (compute), printing)
-static int printing_check(enum printing_instance);
-static void printing_init(void);
 
 /*---------- main energy computation and subroutines ----------*/
 
-static double compute_energy(const Vertices vertices) {
-  double vertex_areas[N], energy;
+double compute_energy(const struct Vertices *vs) {
+  double energy;
   int printing;
 
-  compute_vertex_areas(vertices,vertex_areas);
+  compute_edge_lengths(vs->a);
+  compute_vertex_areas(vs->a);
   energy= 0;
 
   printing= printing_check(pr_cost);
 
   if (printing) printf("cost > energy |");
 
-  COST(1e2, edgewise_vertex_displacement_cost(vertices));
-  COST(1e2, graph_layout_cost(vertices,vertex_areas));
-//  COST(1e4, noncircular_rim_cost(vertices));
+  COST(1e2, edgewise_vertex_displacement_cost(vs->a));
+  COST(1e2, graph_layout_cost(vs->a));
+  COST(1e3, edge_length_variation_cost(vs->a));
+//  COST(1e6, noncircular_rim_cost(vs->a));
 
   if (printing) printf("| total %# e |", energy);
 
@@ -51,7 +41,7 @@ static double compute_energy(const Vertices vertices) {
     if (printing) printf(" BEST");
 
     best_f= fopen(output_file_tmp,"wb");  if (!best_f) diee("fopen new out");
-    r= fwrite(vertices,sizeof(Vertices),1,best_f); if (r!=1) diee("fwrite");
+    r= fwrite(vs->a,sizeof(vs->a),1,best_f); if (r!=1) diee("fwrite");
     if (fclose(best_f)) diee("fclose new best");
     if (rename(output_file_tmp,output_file)) diee("rename install new best");
 
@@ -71,11 +61,20 @@ static void addcost(double *energy, double tweight, double tcost, int pr) {
   *energy += tenergy;
 }
 
-static void compute_vertex_areas(const Vertices vertices, double areas[N]) {
+/*---------- Precomputations ----------*/
+
+void compute_edge_lengths(const Vertices vertices) {
+  int v1,e,v2;
+  
+  FOR_EDGE(v1,e,v2)
+    edge_lengths[v1][e]= hypotD(vertices[v1],vertices[v2]);
+}
+
+void compute_vertex_areas(const Vertices vertices) {
   int v0,v1,v2, e1,e2, k;
 
   FOR_VERTEX(v0) {
-    double total= 0.0;
+    double total= 0.0, edges_total=0;
     int count= 0;
 
     FOR_VEDGE(v0,e1,v1) {
@@ -83,6 +82,8 @@ static void compute_vertex_areas(const Vertices vertices, double areas[N]) {
       v2= EDGE_END2(v0,e2);
       if (v2<0) continue;
 
+      edges_total += edge_lengths[v0][e1];
+
       double e1v[D3], e2v[D3], av[D3];
       K {
 	e1v[k]= vertices[v1][k] - vertices[v0][k];
@@ -90,111 +91,12 @@ static void compute_vertex_areas(const Vertices vertices, double areas[N]) {
       }
       xprod(av, e1v, e2v);
       total += magnD(av);
+      
       count++;
     }
-    areas[v0]= total / count;
-  }
-}
-
-/*---------- use of GSL ----------*/
-
-  /* We want to do multidimensional minimisation.
-   *
-   * We don't think there are any local minima.  Or at least, if there
-   * are, the local minimum which will be found from the starting
-   * state is the one we want.
-   *
-   * We don't want to try to provide a derivative of the cost
-   * function.  That's too tedious (and anyway the polynomial
-   * approximation to our our cost function sometimes has high degree
-   * in the inputs which means the quadratic model implied by most of
-   * the gradient descent minimisers is not ideal).
-   *
-   * This eliminates most of the algorithms.  Nelder and Mead's
-   * simplex algorithm is still available and we will try that.
-   *
-   * In our application we are searching for the optimal locations of
-   * N actualvertices in D3 (3) dimensions - ie, we are searching for
-   * the optimal metapoint in an N*D3-dimensional space.
-   *
-   * So eg with X=Y=100, the simplex will contain 300 metavertices
-   * each of which is an array of 300 doubles for the actualvertex
-   * coordinates.  Hopefully this won't be too slow ...
-   */
-
-static gsl_multimin_fminimizer *minimiser;
-
-static const double stop_epsilon= 1e-6;
-
-static double minfunc_f(const gsl_vector *x, void *params) {
-  assert(x->size == DIM);
-  assert(x->stride == 1);
-  return compute_energy((const double(*)[D3])x->data);
-}
-
-int main(int argc, const char *const *argv) {
-  gsl_multimin_function multimin_function;
-  double size;
-  Vertices initial, step_size;
-  FILE *initial_f;
-  gsl_vector initial_gsl, step_size_gsl;
-  int r, v, k;
-
-  if (argc!=3 || argv[1][0]=='-' || strncmp(argv[2],"-o",2))
-    { fputs("usage: minimise <input> -o<output\n",stderr); exit(8); }
-
-  input_file= argv[1];
-  output_file= argv[2]+2;
-  if (asprintf(&output_file_tmp,"%s.new",output_file) <= 0) diee("asprintf");
-
-  graph_layout_prepare();
-  printing_init();
-  
-  minimiser= gsl_multimin_fminimizer_alloc
-    (gsl_multimin_fminimizer_nmsimplex, DIM);
-  if (!minimiser) { perror("alloc minimiser"); exit(-1); }
-
-  multimin_function.f= minfunc_f;
-  multimin_function.n= DIM;
-  multimin_function.params= 0;
-
-  initial_f= fopen(input_file,"rb");  if (!initial_f) diee("fopen initial");
-  errno= 0; r= fread(initial,sizeof(initial),1,initial_f);
-  if (r!=1) diee("fread");
-  fclose(initial_f);
-
-  initial_gsl.size= DIM;
-  initial_gsl.stride= 1;
-  initial_gsl.block= 0;
-  initial_gsl.owner= 0;
-  step_size_gsl= initial_gsl;
-
-  initial_gsl.data= &initial[0][0];
-  step_size_gsl.data= &step_size[0][0];
-
-  FOR_VERTEX(v)
-    K step_size[v][k]= 0.03;
-//int vx,vy;
-//  FOR_RIM_VERTEX(vx,vy,v)
-//    step_size[v][3] *= 0.1;
-
-  GA( gsl_multimin_fminimizer_set(minimiser, &multimin_function,
-				  &initial_gsl, &step_size_gsl) );
-
-  for (;;) {
-    GA( gsl_multimin_fminimizer_iterate(minimiser) );
-
-    size= gsl_multimin_fminimizer_size(minimiser);
-    r= gsl_multimin_test_size(size, stop_epsilon);
-
-    if (printing_check(pr_size))
-      printf("%*s size %# e, r=%d\n", 135,"", size, r);
-    flushoutput();
-
-    if (r==GSL_SUCCESS) break;
-    assert(r==GSL_CONTINUE);
+    vertex_areas[v0]= total / count;
+    vertex_mean_edge_lengths[v0]= edges_total / count;
   }
-  return 0;
 }
 
 /*---------- Edgewise vertex displacement ----------*/
@@ -265,6 +167,20 @@ double edgewise_vertex_displacement_cost(const Vertices vertices) {
   return total_cost;
 }
 
+/*---------- edge length variation ----------*/
+
+double edge_length_variation_cost(const Vertices vertices) {
+  double diff, cost= 0;
+  int v0, efwd,vfwd, eback;
+
+  FOR_EDGE(v0,efwd,vfwd) {
+    eback= edge_reverse(v0,efwd);
+    diff= edge_lengths[v0][efwd] - edge_lengths[v0][eback];
+    cost += diff*diff;
+  }
+  return cost;
+}    
+
 /*---------- noncircular rim cost ----------*/
 
 double noncircular_rim_cost(const Vertices vertices) {
@@ -286,56 +202,3 @@ double noncircular_rim_cost(const Vertices vertices) {
   }
   return cost;
 }
-
-/*---------- printing rate limit ----------*/
-
-static volatile unsigned print_todo;
-static sigset_t print_alarmset;
-
-static int printing_check(enum printing_instance which) {
-  static int skipped[pr__max];
-  
-  unsigned bits= 1u << which;
-  int sk;
-
-  if (!(print_todo & bits)) {
-    skipped[which]++;
-    return 0;;
-  }
-
-  sigprocmask(SIG_BLOCK,&print_alarmset,0);
-  print_todo &= ~bits;
-  sigprocmask(SIG_UNBLOCK,&print_alarmset,0);
-
-  sk= skipped[which];
-  if (sk) printf("[%4d] ",sk);
-  else printf("       ");
-  skipped[which]= 0;
-
-  return 1;
-}
-
-static void alarmhandler(int ignored) {
-  print_todo= ~0u;
-}
-
-static void printing_init(void) {
-  struct sigaction sa;
-  struct itimerval itv;
-
-  sigemptyset(&print_alarmset);
-  sigaddset(&print_alarmset,SIGALRM);
-
-  sa.sa_handler= alarmhandler;
-  sa.sa_mask= print_alarmset;
-  sa.sa_flags= SA_RESTART;
-  if (sigaction(SIGALRM,&sa,0)) diee("sigaction ALRM");
-  
-  itv.it_interval.tv_sec= 0;
-  itv.it_interval.tv_usec= 200000;
-  itv.it_value= itv.it_interval;
-
-  if (setitimer(ITIMER_REAL,&itv,0)) diee("setitimer REAL");
-
-  raise(SIGALRM);
-}