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authoreunhhu <[email protected]>2026-10-09 15:56:48 +0100
committereunhhu <[email protected]>2026-10-09 15:56:48 +0100
commit75aa418924fbaf510174713aa007482169bbd114 (patch)
tree23d852a9cbb53bc3b7b6c4ee2700f0375399a881 /research/experiments
parentf47f0caa14889013436438f2bcb2c482a58e630b (diff)
downloadpure-75aa418924fbaf510174713aa007482169bbd114.tar.gz
pure-75aa418924fbaf510174713aa007482169bbd114.zip
043 programs (research 139, in progress): a batch loop's body as the program a load would make, interpreted a step at a time (scalar steps by the executor's rules, kernel steps over four-byte lane registers fixed at load with two buffers each, a list's cells once a batch, a deferred set after its distance check), against the same kernels called straight and natural.h's C: matmul 10.36 ms (straight 7.17; the executor's 25.8 with 3.6 of making), knapsack 4.16 (straight 3.76; the executor's 8.19); 139's question, bars and b20's split (matmul's 11.1 ms of interpretation, knapsack's 1.9)
Diffstat (limited to 'research/experiments')
-rw-r--r--research/experiments/043-programs/2026-10-09-programs.jsonl22
-rw-r--r--research/experiments/043-programs/programs.c383
2 files changed, 405 insertions, 0 deletions
diff --git a/research/experiments/043-programs/2026-10-09-programs.jsonl b/research/experiments/043-programs/2026-10-09-programs.jsonl
new file mode 100644
index 0000000..12c5ebb
--- /dev/null
+++ b/research/experiments/043-programs/2026-10-09-programs.jsonl
@@ -0,0 +1,22 @@
+{"turn":1,"body":"matmul","way":"program","ms":10.360,"same":true}
+{"turn":1,"body":"matmul","way":"direct","ms":7.172,"same":true}
+{"turn":1,"body":"matmul","way":"c","ms":5.093,"same":true}
+{"turn":1,"body":"knapsack","way":"program","ms":4.155,"same":true}
+{"turn":1,"body":"knapsack","way":"direct","ms":3.756,"same":true}
+{"turn":1,"body":"knapsack","way":"c","ms":6.238,"same":true}
+{"turn":2,"body":"matmul","way":"program","ms":10.360,"same":true}
+{"turn":2,"body":"matmul","way":"direct","ms":7.172,"same":true}
+{"turn":2,"body":"matmul","way":"c","ms":4.940,"same":true}
+{"turn":2,"body":"knapsack","way":"program","ms":4.185,"same":true}
+{"turn":2,"body":"knapsack","way":"direct","ms":3.771,"same":true}
+{"turn":2,"body":"knapsack","way":"c","ms":6.246,"same":true}
+{"turn":3,"body":"matmul","way":"program","ms":10.357,"same":true}
+{"turn":3,"body":"matmul","way":"direct","ms":7.131,"same":true}
+{"turn":3,"body":"matmul","way":"c","ms":5.080,"same":true}
+{"turn":3,"body":"knapsack","way":"program","ms":4.148,"same":true}
+{"turn":3,"body":"knapsack","way":"direct","ms":3.756,"same":true}
+{"turn":3,"body":"knapsack","way":"c","ms":6.228,"same":true}
+{"body":"matmul","way":"program","rounds":3,"instructions":258225660,"cycles":87893964}
+{"body":"matmul","way":"direct","rounds":3,"instructions":172357595,"cycles":64793489}
+{"body":"knapsack","way":"program","rounds":3,"instructions":150648952,"cycles":45677427}
+{"body":"knapsack","way":"direct","rounds":3,"instructions":140963637,"cycles":42315130}
diff --git a/research/experiments/043-programs/programs.c b/research/experiments/043-programs/programs.c
new file mode 100644
index 0000000..3d1fbdf
--- /dev/null
+++ b/research/experiments/043-programs/programs.c
@@ -0,0 +1,383 @@
+/* Research 139's deciding experiment: a batch loop's body as the program a
+ * load would make of it (not built yet: docs/research/139), interpreted a
+ * step at a time by one switch. Scalar steps make the uniform and affine
+ * values as the executor's rules do (a number's arithmetic finite, an affine
+ * value's parts whole within 2^52, a DENSE key's row whole and in range);
+ * kernel steps run over four-byte lanes in registers fixed at load (no
+ * buffer sought at run time); a list's cells are read once a batch; a row
+ * range is checked at its ends; sums and products past 2^32 fail the batch;
+ * a set waits for the batch's end, after its reads' distance is checked.
+ * The bodies are the suite's as their bytecode has them:
+ * matmul the j loop a batch (200 lanes), k's rounds together:
+ * s = s + a[i * n + k].v * b[k * n + j].v
+ * knapsack each item's rounds a batch (1024 lanes): c = capacity - k,
+ * with = table[c - w].best + v, if with > table[c].best { set }
+ * Each also with the same kernels called straight from C, the scalars made
+ * in C (direct: no interpretation), against natural.h's C.
+ * cc -O3 -falign-loops=64 -std=c17 -I../040-against-c programs.c -lm -o programs
+ * ./programs [matmul|knapsack] [program|direct|c|all] [rounds] (one JSON line each) */
+#define _POSIX_C_SOURCE 200809L
+#include <math.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include "natural.h"
+
+static double now(void) {
+ struct timespec t;
+ clock_gettime(CLOCK_MONOTONIC, &t);
+ return t.tv_sec * 1e3 + t.tv_nsec / 1e6;
+}
+
+enum { LANES = 1024, SREGS = 16, LREGS = 8 };
+
+/* ---- Kernels (as module-batch.c's words_op, cells_at, put_words), each its own function: inlined in run()'s switch,
+ * GCC made them scalar (their lanes' pointers from one struct) */
+
+__attribute__((noinline)) static bool k_mulk(uint32_t *restrict out, const uint32_t *restrict xs, uint32_t k, unsigned n) {
+ uint32_t over = 0;
+ for (unsigned l = 0; l < n; ++l) { uint64_t p = (uint64_t)xs[l] * k; out[l] = (uint32_t)p, over |= (uint32_t)(p >> 32); }
+ return !over;
+}
+__attribute__((noinline)) static bool k_addk(uint32_t *restrict out, const uint32_t *restrict xs, uint32_t k, unsigned n) {
+ uint32_t over = 0;
+ for (unsigned l = 0; l < n; ++l) { uint32_t s = xs[l] + k; out[l] = s, over |= s < k; }
+ return !over;
+}
+__attribute__((noinline)) static bool k_add(uint32_t *restrict out, const uint32_t *restrict xs, const uint32_t *restrict ys, unsigned n) {
+ uint32_t over = 0;
+ for (unsigned l = 0; l < n; ++l) { uint32_t s = xs[l] + ys[l]; out[l] = s, over |= s < xs[l]; }
+ return !over;
+}
+__attribute__((noinline)) static unsigned k_gt(uint32_t *restrict out, const uint32_t *restrict xs, const uint32_t *restrict ys, unsigned n) {
+ uint32_t count = 0;
+ for (unsigned l = 0; l < n; ++l) { uint32_t t = xs[l] > ys[l]; out[l] = t, count += t; }
+ return count;
+}
+/* a one-byte column's cells at rows first + lane: four-byte lanes */
+__attribute__((noinline)) static void k_widen(uint32_t *restrict out, const uint8_t *restrict from, unsigned n) {
+ for (unsigned l = 0; l < n; ++l) out[l] = from[l];
+}
+__attribute__((noinline)) static void k_put_masked(uint32_t *restrict to, const uint32_t *restrict from, const uint32_t *restrict mask, unsigned n) {
+ for (unsigned l = 0; l < n; ++l) to[l] = mask[l] ? from[l] : to[l];
+}
+
+/* ---- Lists as a batch reads them: a DENSE list's column (each key its row) */
+
+typedef struct { size_t count; void *column; uint8_t width; } Cells;
+
+/* ---- The program */
+
+enum {
+ S_FIELD, /* s[d] = the message's field arg */
+ S_LOCAL, /* s[d] = local arg (a local the block does not set) */
+ S_ROUND, /* s[d] = the nested loop's round (uniform) */
+ S_LANE, /* s[d] = the batch loop's value (affine: first, lane_step) */
+ S_MUL, /* s[d] = s[a] * s[b] (uniform by uniform, or uniform by affine) */
+ S_ADD, /* s[d] = s[a] + s[b] */
+ S_SUB, /* s[d] = s[a] - s[b] */
+ S_GET, /* s[d] = list arg's field at the row of key s[a] (uniform; DENSE: the key its row) */
+ K_READ, /* L[d] = list arg's field at affine rows s[a] (four bytes: the column itself; one byte: made four) */
+ K_MULK, /* L[d] = L[a] * s[b] */
+ K_ADDK, /* L[d] = L[a] + s[b] */
+ K_ADD, /* L[d] = L[a] + L[b] */
+ K_GT, /* L[d] = L[a] > L[b], its 1s counted (a branch's lanes) */
+ K_IF, /* none of L[a]'s lanes: on past the next b steps */
+ K_SET, /* list arg's field at affine rows s[a] = L[b] in L[d]'s lanes, at the batch's end */
+};
+typedef struct { uint8_t op, d, a, b; uint32_t arg; } Step;
+typedef struct { double value, step; bool affine; } Scalar;
+typedef struct { uint32_t list; Scalar rows; const uint32_t *value, *mask; } Set;
+
+typedef struct {
+ Scalar s[SREGS];
+ const uint32_t *lane[LREGS]; /* each lane register's lanes: its own, or a column's */
+ uint32_t own[LREGS][2][LANES + 24]; /* each two (laid out at load, not 4 KB apart as the executor's buffers): a result never its operand's */
+ unsigned ones[LREGS];
+ const uint32_t *field; /* the message */
+ const double *local;
+ double round, first, lane_step;
+ unsigned n;
+ Cells cells[4]; /* each list's, once a batch */
+ Set sets[2];
+ unsigned set_count;
+ bool failed;
+} Machine;
+
+static bool whole(double x) { return x == floor(x) && fabs(x) <= 0x1p52 && !(x == 0 && signbit(x)); }
+/* value + step × lane, as affine_of: whole parts at both ends (else the executor makes lanes; here the batch fails) */
+static bool affine(Machine *M, double value, double step, Scalar *out) {
+ if (!whole(value) || !whole(step) || !whole(value + step * (M->n - 1))) return false;
+ *out = (Scalar){value, step, step != 0};
+ return true;
+}
+/* a op b of scalars as the executor's rules: uniforms as numbers (finite), affine values as affine_op */
+static bool scalar_op(Machine *M, uint8_t op, const Scalar *a, const Scalar *b, Scalar *out) {
+ if (!a->affine && !b->affine) {
+ double v = op == S_MUL ? a->value * b->value : op == S_ADD ? a->value + b->value : a->value - b->value;
+ if (!isfinite(v)) return false;
+ *out = (Scalar){v, 0, false};
+ return true;
+ }
+ if ((!a->affine && !whole(a->value)) || (!b->affine && !whole(b->value))) return false;
+ double as = a->affine ? a->step : 0, bs = b->affine ? b->step : 0;
+ switch (op) {
+ case S_ADD: return affine(M, a->value + b->value, as + bs, out);
+ case S_SUB: return affine(M, a->value - b->value, as - bs, out);
+ default:
+ if (!a->affine && a->value > 0) return affine(M, a->value * b->value, a->value * bs, out);
+ if (!b->affine && b->value > 0) return affine(M, a->value * b->value, as * b->value, out);
+ return false;
+ }
+}
+
+/* Where register d's result goes: of its two buffers the one neither operand holds (s = s + e: the other). */
+static uint32_t *target(Machine *M, unsigned d, unsigned a, unsigned b) {
+ uint32_t *out = M->own[d][0];
+ return out == M->lane[a] || out == M->lane[b] ? M->own[d][1] : out;
+}
+
+/* The program's steps once for the batch's lanes (a nested loop's round once). false: the batch fails (the executor's rounds). */
+static bool run(const Step *prog, unsigned count, Machine *M) {
+ unsigned n = M->n;
+ for (unsigned i = 0; i < count; ++i) {
+ const Step *p = &prog[i];
+ switch (p->op) {
+ case S_FIELD: M->s[p->d] = (Scalar){M->field[p->arg], 0, false}; break;
+ case S_LOCAL: M->s[p->d] = (Scalar){M->local[p->arg], 0, false}; break;
+ case S_ROUND: M->s[p->d] = (Scalar){M->round, 0, false}; break;
+ case S_LANE:
+ if (!affine(M, M->first, M->lane_step, &M->s[p->d])) return false;
+ break;
+ case S_MUL: case S_ADD: case S_SUB:
+ if (!scalar_op(M, p->op, &M->s[p->a], &M->s[p->b], &M->s[p->d])) return false;
+ break;
+ case S_GET: {
+ const Cells *c = &M->cells[p->arg];
+ double k = M->s[p->a].value;
+ if (M->s[p->a].affine || !(k >= 0 && k < (double)c->count && k == floor(k))) return false;
+ size_t row = (size_t)k;
+ M->s[p->d] = (Scalar){c->width == 1 ? ((const uint8_t *)c->column)[row] : ((const uint32_t *)c->column)[row], 0, false};
+ break;
+ }
+ case K_READ: {
+ const Cells *c = &M->cells[p->arg];
+ const Scalar *r = &M->s[p->a];
+ double end = r->value + r->step * (n - 1);
+ if (!r->affine || r->step != 1 || !(r->value >= 0 && end < (double)c->count)) return false; /* (the executor's other ways) */
+ size_t first = (size_t)r->value;
+ if (c->width == 4) M->lane[p->d] = (const uint32_t *)c->column + first; /* a view */
+ else k_widen(M->own[p->d][0], (const uint8_t *)c->column + first, n), M->lane[p->d] = M->own[p->d][0];
+ break;
+ }
+ case K_MULK: {
+ uint32_t *out = target(M, p->d, p->a, p->a);
+ if (M->s[p->b].affine || !(M->s[p->b].value >= 0 && M->s[p->b].value < 4294967296.0) ||
+ !k_mulk(out, M->lane[p->a], (uint32_t)M->s[p->b].value, n))
+ return false;
+ M->lane[p->d] = out;
+ break;
+ }
+ case K_ADDK: {
+ uint32_t *out = target(M, p->d, p->a, p->a);
+ if (M->s[p->b].affine || !(M->s[p->b].value >= 0 && M->s[p->b].value < 4294967296.0) ||
+ !k_addk(out, M->lane[p->a], (uint32_t)M->s[p->b].value, n))
+ return false;
+ M->lane[p->d] = out;
+ break;
+ }
+ case K_ADD: {
+ uint32_t *out = target(M, p->d, p->a, p->b);
+ if (!k_add(out, M->lane[p->a], M->lane[p->b], n)) return false;
+ M->lane[p->d] = out;
+ break;
+ }
+ case K_GT: {
+ uint32_t *out = target(M, p->d, p->a, p->b);
+ M->ones[p->d] = k_gt(out, M->lane[p->a], M->lane[p->b], n);
+ M->lane[p->d] = out;
+ break;
+ }
+ case K_IF:
+ if (!M->ones[p->a]) i += p->b;
+ break;
+ case K_SET:
+ if (M->set_count == 2) return false;
+ M->sets[M->set_count++] = (Set){p->arg, M->s[p->a], M->lane[p->b], M->ones[p->d] == n ? NULL : M->lane[p->d]};
+ break;
+ }
+ }
+ return true;
+}
+
+/* ---- matmul */
+
+static uint64_t minstd_x;
+static uint32_t minstd_next(void) { return (uint32_t)(minstd_x = minstd_x * 48271 % 2147483647); }
+
+/* The j loop a batch (as the executor runs it: the lanes j, k's rounds together), s in lane register 0. */
+static double matmul_program(uint32_t n, const uint8_t *a, const uint8_t *b, double *last, uint64_t *work) {
+ static Machine M;
+ enum { R_I, R_N, R_IN, R_K, R_KEYA, R_AV, R_KN, R_J, R_ROWS };
+ const Step body[] = {
+ {S_LOCAL, R_I, 0, 0, 0}, {S_FIELD, R_N, 0, 0, 0}, {S_MUL, R_IN, R_I, R_N, 0}, {S_ROUND, R_K, 0, 0, 0},
+ {S_ADD, R_KEYA, R_IN, R_K, 0}, {S_GET, R_AV, R_KEYA, 0, 0}, /* a[i * n + k].v */
+ {S_MUL, R_KN, R_K, R_N, 0}, {S_LANE, R_J, 0, 0, 0}, {S_ADD, R_ROWS, R_KN, R_J, 0},
+ {K_READ, 1, R_ROWS, 0, 1}, /* b[k * n + j].v */
+ {K_MULK, 2, 1, R_AV, 0}, {K_ADD, 0, 0, 2, 0}, /* s = s + ... */
+ };
+ double local[1], total = 0;
+ uint32_t field[1] = {n};
+ M.field = field, M.local = local, M.n = n, M.first = 0, M.lane_step = 1;
+ for (uint32_t i = 0; i < n; ++i) {
+ local[0] = i;
+ M.cells[0] = (Cells){(size_t)n * n, (void *)a, 1}, M.cells[1] = (Cells){(size_t)n * n, (void *)b, 1}; /* once a batch */
+ memset(M.own[0][0], 0, n * sizeof(uint32_t)), M.lane[0] = M.own[0][0]; /* let s = 0 */
+ for (uint32_t k = 0; k < n; ++k) {
+ M.round = k;
+ *work += n * (uint64_t)(sizeof(body) / sizeof(body[0]) + 1);
+ if (!run(body, sizeof(body) / sizeof(body[0]), &M)) return NAN;
+ }
+ uint64_t sum = 0;
+ for (uint32_t l = 0; l < n; ++l) sum += M.lane[0][l];
+ total += (double)sum, *last = M.lane[0][n - 1];
+ }
+ return total;
+}
+
+/* The same kernels called straight, the scalars made in C. */
+static double matmul_direct(uint32_t n, const uint8_t *a, const uint8_t *b, double *last) {
+ static uint32_t s[2][LANES + 24], x[LANES + 24], y[LANES + 24]; /* s two (a result never its operand), as the program's */
+ double total = 0;
+ for (uint32_t i = 0; i < n; ++i) {
+ unsigned t = 0;
+ memset(s[0], 0, n * sizeof(uint32_t));
+ for (uint32_t k = 0; k < n; ++k, t ^= 1) {
+ k_widen(x, b + (size_t)k * n, n);
+ if (!k_mulk(y, x, a[(size_t)i * n + k], n) || !k_add(s[t ^ 1], s[t], y, n)) return NAN;
+ }
+ uint64_t sum = 0;
+ for (uint32_t l = 0; l < n; ++l) sum += s[t][l];
+ total += (double)sum, *last = s[t][n - 1];
+ }
+ return total;
+}
+
+/* ---- knapsack */
+
+/* Each item's rounds a batch, lanes in memory's order (the executor numbers them so after its first batch). */
+static double knapsack_program(uint32_t items, uint32_t capacity, const uint32_t *weight, const uint32_t *worth, uint32_t *best, uint64_t *work) {
+ static Machine M;
+ enum { R_CAP, R_K, R_C, R_W, R_CW, R_V };
+ const Step body[] = {
+ {S_FIELD, R_CAP, 0, 0, 0}, {S_LANE, R_K, 0, 0, 0}, {S_SUB, R_C, R_CAP, R_K, 0}, /* c = capacity - k (lanes: -k) */
+ {S_LOCAL, R_W, 0, 0, 0}, {S_SUB, R_CW, R_C, R_W, 0}, /* c - it.weight */
+ {K_READ, 1, R_CW, 0, 0}, {S_LOCAL, R_V, 0, 0, 1}, {K_ADDK, 2, 1, R_V, 0}, /* with = table[c - w].best + it.worth */
+ {K_READ, 3, R_C, 0, 0}, {K_GT, 4, 2, 3, 0}, /* with > table[c].best */
+ {K_IF, 0, 4, 1, 0}, {K_SET, 4, R_C, 2, 0}, /* table[c].best = with */
+ };
+ double local[2];
+ uint32_t field[1] = {capacity};
+ M.field = field, M.local = local;
+ for (uint32_t i = 0; i < items; ++i) {
+ local[0] = weight[i], local[1] = worth[i];
+ uint32_t rounds = capacity + 1 - weight[i];
+ for (uint32_t k0 = 0; k0 < rounds; k0 += LANES) {
+ unsigned n = rounds - k0 < LANES ? rounds - k0 : LANES;
+ /* lanes in memory's order: lane l is round k0 + n - 1 - l (c = capacity - k ascending in l) */
+ M.n = n, M.first = (double)(k0 + n - 1), M.lane_step = -1, M.set_count = 0;
+ field[0] = capacity;
+ M.cells[0] = (Cells){(size_t)capacity + 1, best, 4}; /* once a batch */
+ *work += n * (uint64_t)(sizeof(body) / sizeof(body[0]) + 1);
+ if (!run(body, sizeof(body) / sizeof(body[0]), &M)) return NAN;
+ for (unsigned t = 0; t < M.set_count; ++t) { /* the end: the set's rows against the reads' (distance w >= 0: none of these rounds reads what an earlier one sets), then set */
+ const Set *s = &M.sets[t];
+ double d = M.s[R_CW].value - s->rows.value; /* the read c - w against the set c, both step 1 */
+ if (!(d <= 0 && d == floor(d))) return NAN;
+ uint32_t *to = best + (size_t)s->rows.value;
+ if (s->mask) k_put_masked(to, s->value, s->mask, n);
+ else memcpy(to, s->value, n * sizeof(uint32_t));
+ }
+ }
+ }
+ return best[capacity];
+}
+
+static double knapsack_direct(uint32_t items, uint32_t capacity, const uint32_t *weight, const uint32_t *worth, uint32_t *best) {
+ static uint32_t with[LANES], gt[LANES];
+ for (uint32_t i = 0; i < items; ++i) {
+ uint32_t w = weight[i], v = worth[i], rounds = capacity + 1 - w;
+ for (uint32_t k0 = 0; k0 < rounds; k0 += LANES) {
+ unsigned n = rounds - k0 < LANES ? rounds - k0 : LANES;
+ size_t low = capacity - (k0 + n - 1);
+ if (!k_addk(with, best + low - w, v, n)) return NAN;
+ unsigned ones = k_gt(gt, with, best + low, n);
+ if (!ones) continue;
+ if (ones == n) memcpy(best + low, with, n * sizeof(uint32_t));
+ else k_put_masked(best + low, with, gt, n);
+ }
+ }
+ return best[capacity];
+}
+
+/* ---- */
+
+static int cmp(const void *a, const void *b) { double x = *(const double *)a, y = *(const double *)b; return (x > y) - (x < y); }
+
+int main(int argc, char **argv) {
+ const char *body = argc > 1 ? argv[1] : "all", *way = argc > 2 ? argv[2] : "all";
+ int rounds = argc > 3 ? atoi(argv[3]) : 11;
+ bool all = !strcmp(way, "all");
+ double *ms = malloc(rounds * sizeof(double)), out[4];
+ if (!strcmp(body, "all") || !strcmp(body, "matmul")) {
+ uint32_t n = 200, in[2] = {n, 0};
+ uint8_t *a = malloc((size_t)n * n), *b = malloc((size_t)n * n);
+ minstd_x = 1;
+ for (uint32_t i = 0; i < n * n; ++i) a[i] = (uint8_t)(minstd_next() % 100), b[i] = (uint8_t)(minstd_next() % 100);
+ c_matmul(in, out);
+ double want = out[0];
+ for (int w = 0; w < 3; ++w) {
+ const char *name = w == 0 ? "program" : w == 1 ? "direct" : "c";
+ if (!all && strcmp(way, name)) continue;
+ double got = 0, last = 0;
+ uint64_t work = 0;
+ for (int r = 0; r < rounds; ++r) {
+ double t = now();
+ if (w == 0) got = matmul_program(n, a, b, &last, &work);
+ else if (w == 1) got = matmul_direct(n, a, b, &last);
+ else c_matmul(in, out), got = out[0];
+ ms[r] = now() - t;
+ }
+ qsort(ms, rounds, sizeof(double), cmp);
+ printf("{\"body\":\"matmul\",\"way\":\"%s\",\"ms\":%.3f,\"same\":%s}\n", name, ms[rounds / 2], got == want ? "true" : "false");
+ }
+ }
+ if (!strcmp(body, "all") || !strcmp(body, "knapsack")) {
+ uint32_t items = 100, capacity = 50000, in[2] = {items, capacity};
+ uint32_t *weight = malloc(4 * items), *worth = malloc(4 * items), *best = malloc(4 * (capacity + 1));
+ minstd_x = 1;
+ for (uint32_t i = 0; i < items; ++i) weight[i] = minstd_next() % 1000 + 1, worth[i] = minstd_next() % 1000;
+ c_knapsack(in, out);
+ double want = out[0];
+ for (int w = 0; w < 3; ++w) {
+ const char *name = w == 0 ? "program" : w == 1 ? "direct" : "c";
+ if (!all && strcmp(way, name)) continue;
+ double got = 0;
+ uint64_t work = 0;
+ for (int r = 0; r < rounds; ++r) {
+ memset(best, 0, 4 * (capacity + 1));
+ double t = now();
+ if (w == 0) got = knapsack_program(items, capacity, weight, worth, best, &work);
+ else if (w == 1) got = knapsack_direct(items, capacity, weight, worth, best);
+ else c_knapsack(in, out), got = out[0];
+ ms[r] = now() - t;
+ }
+ qsort(ms, rounds, sizeof(double), cmp);
+ printf("{\"body\":\"knapsack\",\"way\":\"%s\",\"ms\":%.3f,\"same\":%s}\n", name, ms[rounds / 2], got == want ? "true" : "false");
+ }
+ }
+ return 0;
+}