Merge remote-tracking branch 'sgt/master'

Changes made to the new code in sgt/master:
  - use "-std=gnu99" not "--std=gnu99"
  - n_over_best calculation is in set_best
  - n_over_best initialised properly
 style:
  - use calloc, do not cast return value from int, better sizeof
  - extra blank line

Conflicts:
	Makefile
	main.c

diff --cc main.c
index fd0569be80e712602988a5f79207b77bcb45ff5b,3c1b123b2e71155b058bdc34d45f058f6db592f9..2fc3a51f86979e5468fb4237cdd4efb760e4d089
--- 1/main.c
--- 2/main.c
+++ b/main.c
@@@ -94,240 -86,11 +94,244 @@@ static double best
  static glp_prob *best_prob;
  static AdjWord *best_adjmatrix;
  
+ static int n_over_best;
+ static int *weight;
+ 
  static unsigned printcounter;
  
 +static void iterate(void);
 +static void iterate_recurse(int i, AdjWord min);
 +static bool preconsider_ok(int nwords, bool doprint);
 +static bool maxhamweight_ok(void);
 +static void optimise(bool doprint);
 +
 +static void progress_eol(void) {
 +  fprintf(stderr,"        \r");
 +  fflush(stderr);
 +}
 +
 +static void set_best(double new_best) {
 +  best = new_best;
++  n_over_best = n / best;
 +}
 +
 +/*----- multicore support -----*/
 +
 +/*
 + * Multicore protocol
 + *
 + * We fork into:
 + *   - master (parent)
 + *   - generator
 + *   - ncpu workers
 + *
 + * ipc facilities:
 + *   - one pipe ("work") from generator to workers
 + *   - ever-extending file ("bus") containing new "best" values
 + *   - one file for each worker giving maxhamweight and adjmatrix for best
 + *
 + * generator runs iterate_recurse to a certain depth and writes the
 + * candidates to a pipe
 + *
 + * workers read candidates from the pipe and resume iterate_recurse
 + * halfway through the recursion
 + *
 + * whenever a worker does a doprint, it checks the bus for new best
 + * value; actual best values are appended
 + *
 + * master waits for generator and all workers to finish and then
 + * runs optimise() for each worker's best, then prints
 + */ 
 +
 +static int ncpus = 0, multicore_iteration_boundary = INT_MAX;
 +
 +static int mc_bus, mc_work[2];
 +static off_t mc_bus_read;
 +
 +typedef struct {
 +  int w;
 +  FILE *results;
 +  pid_t pid;
 +} Worker;
 +static Worker *mc_us;
 +
 +static void multicore_check_for_new_best(void);
 +
 +#define MAX_NIOVS 3
 +static AdjWord mc_iter_min;
 +static int mc_niovs;
 +static size_t mc_iovlen;
 +static struct iovec mc_iov[MAX_NIOVS];
 +
 +#define IOV0 (mc_niovs = mc_iovlen = 0)
 +
 +#define IOV(obj, count) ({                            \
 +    assert(mc_niovs < MAX_NIOVS);                     \
 +    mc_iov[mc_niovs].iov_base = &(obj);                       \
 +    mc_iov[mc_niovs].iov_len = sizeof(obj) * (count); \
 +    mc_iovlen += mc_iov[mc_niovs].iov_len;              \
 +    mc_niovs++;                                               \
 +  })
 +
 +static void mc_rwvsetup_outer(void) {
 +  IOV0;
 +  IOV(maxhamweight, 1);
 +  IOV(mc_iter_min, 1);
 +  IOV(*adjmatrix, multicore_iteration_boundary);
 +}
 +
 +static void mc_rwvsetup_full(void) {
 +  IOV0;
 +  IOV(*adjmatrix, n);
 +}
 +
 +static void vlprintf(const char *fmt, va_list al) {
 +  vfprintf(stderr,fmt,al);
 +  progress_eol();
 +}
 +
 +static void LPRINTF(const char *fmt, ...) {
 +  va_list al;
 +  va_start(al,fmt);
 +  vlprintf(fmt,al);
 +  va_end(al);
 +}
 +
 +static void mc_awaitpid(int wnum, pid_t pid) {
 +  LPRINTF("master awaiting %2d [%ld]",wnum,(long)pid);
 +  int status;
 +  pid_t got = waitpid(pid, &status, 0);
 +  assert(got == pid);
 +  if (status) {
 +    fprintf(stderr,"\nFAILED SUBPROC %2d [%ld] %d\n",
 +          wnum, (long)pid, status);
 +    exit(-1);
 +  }
 +}
 +
 +static void multicore_outer_iteration(int i, AdjWord min) {
 +  static unsigned check_counter;
 +
 +  assert(i == multicore_iteration_boundary);
 +  mc_iter_min = min;
 +  mc_rwvsetup_outer();
 +  ssize_t r = writev(mc_work[1], mc_iov, mc_niovs);
 +  assert(r == mc_iovlen);
 +  /* effectively, this writev arranges to transfers control
 +   * to some worker's instance of iterate_recurse via mc_iterate_worker */
 +
 +  if (!(check_counter++ & 0xff))
 +    multicore_check_for_new_best();
 +}
 +
 +static void mc_iterate_worker(void) {
 +  for (;;) {
 +    mc_rwvsetup_outer();
 +    ssize_t r = readv(mc_work[0], mc_iov, mc_niovs);
 +    if (r == 0) break;
 +    assert(r == mc_iovlen);
 +    
 +    bool ok = maxhamweight_ok();
 +    if (!ok) continue;
 +
 +    ok = preconsider_ok(multicore_iteration_boundary, 1);
 +    progress_eol();
 +    if (!ok) continue;
 +
 +    /* stop iterate_recurse from trying to run multicore_outer_iteration */
 +    int mc_org_it_bound = multicore_iteration_boundary;
 +    multicore_iteration_boundary = INT_MAX;
 +    iterate_recurse(mc_org_it_bound, mc_iter_min);
 +    multicore_iteration_boundary = mc_org_it_bound;
 +  }
 +  LPRINTF("worker %2d reporting",mc_us->w);
 +  if (best_adjmatrix) {
 +    adjmatrix = best_adjmatrix;
 +    mc_rwvsetup_full();
 +    ssize_t r = writev(fileno(mc_us->results), mc_iov, mc_niovs);
 +    assert(r == mc_iovlen);
 +  }
 +  LPRINTF("worker %2d ending",mc_us->w);
 +  exit(0);
 +}
 +
 +static void multicore(void) {
 +  Worker *mc_workers;
 +  int w;
 +  pid_t genpid;
 +
 +  multicore_iteration_boundary = n / 2;
 +
 +  FILE *busf = tmpfile();  assert(busf);
 +  mc_bus = fileno(busf);
 +  int r = fcntl(mc_bus, F_GETFL);  assert(r >= 0);
 +  r |= O_APPEND;
 +  r = fcntl(mc_bus, F_SETFL, r);  assert(r >= 0);
 +
 +  r = pipe(mc_work);  assert(!r);
 +
 +  mc_workers = xmalloc(sizeof(*mc_workers) * ncpus);
 +  for (w=0; w<ncpus; w++) {
 +    mc_workers[w].w = w;
 +    mc_workers[w].results = tmpfile();  assert(mc_workers[w].results);
 +    mc_workers[w].pid = fork();  assert(mc_workers[w].pid >= 0);
 +    if (!mc_workers[w].pid) {
 +      mc_us = &mc_workers[w];
 +      close(mc_work[1]);
 +      LPRINTF("worker %2d running", w);
 +      mc_iterate_worker();
 +      exit(0);
 +    }
 +  }
 +
 +  close(mc_work[0]);
 +
 +  genpid = fork();  assert(genpid >= 0);
 +  if (!genpid) {
 +    LPRINTF("generator running");
 +    iterate();
 +    exit(0);
 +  }
 +
 +  close(mc_work[1]);
 +  mc_awaitpid(-1, genpid);
 +  for (w=0; w<ncpus; w++)
 +    mc_awaitpid(w, mc_workers[w].pid);
 +
 +  for (w=0; w<ncpus; w++) {
 +    mc_rwvsetup_full();
 +    LPRINTF("reading report from %2d",w);
 +    ssize_t sr = preadv(fileno(mc_workers[w].results), mc_iov, mc_niovs, 0);
 +    if (!sr) continue;
 +    maxhamweight = 0;
 +    optimise(1);
 +  }
 +}
 +
 +static void multicore_check_for_new_best(void) {
 +  if (!ncpus) return;
 +
 +  for (;;) {
 +    double msg;
 +    ssize_t got = pread(mc_bus, &msg, sizeof(msg), mc_bus_read);
 +    if (!got) break;
 +    assert(got == sizeof(msg));
 +    if (msg > best)
 +      set_best(msg);
 +    mc_bus_read += sizeof(msg);
 +  }
 +}
 +
 +static void multicore_found_new_best(void) {
 +  if (!ncpus) return;
 +
 +  if (mc_us /* might be master */) fprintf(stderr,"    w%-2d ",mc_us->w);
 +  ssize_t wrote = write(mc_bus, &best, sizeof(best));
 +  assert(wrote == sizeof(best));
 +}
 +
 +/*----- end of multicore support -----*/
 +
  static AdjWord *xalloc_adjmatrix(void) {
    return xmalloc(sizeof(*adjmatrix)*n);
  }
@@@ -336,7 -99,9 +340,9 @@@ static void prep(void) 
    adjall = ~((~(AdjWord)0) << m);
    adjmatrix = xalloc_adjmatrix();
    glp_term_out(GLP_OFF);
 -  n_over_best = n / best;
 -  weight = (int *)malloc(m*sizeof(int));
 -  for (int j = 0; j < m; j++) weight[j] = 0;
 +  setlinebuf(stderr);
++  weight = calloc(sizeof(*weight), m);  assert(weight);
++  n_over_best = INT_MAX;
  }
  
  static AdjWord one_adj_bit(int bitnum) {
@@@ -597,9 -338,20 +603,21 @@@ static void iterate_recurse(int i, AdjW
        goto again;
      if (i == 0 && (adjmatrix[i] & (1+adjmatrix[i])))
        goto again;
 -      if (adjmatrix[i] & (1 << j))
 +
+     for (int j = 0; j < m; j++)
++      if (adjmatrix[i] & one_adj_bit(j))
+         weight[j]++;
+     for (int j = 0; j < m; j++)
+       if (weight[j] >= n_over_best)
+         goto takeout;
+ 
      iterate_recurse(i+1, adjmatrix[i]);
  
 -   takeout:
++  takeout:
+     for (int j = 0; j < m; j++)
 -      if (adjmatrix[i] & (1 << j))
++      if (adjmatrix[i] & one_adj_bit(j))
+         weight[j]--;
+ 
    again:
      if (adjmatrix[i] == adjall)
        return;