void mexFunction (int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
unsigned char *X8, *B8; double *X, *B; int N;
int k;
double *y;
//--
// UINT8 image
//--
if (mxIsUint8(prhs[0])) {
//--
// INPUT
//--
// input image
X8 = (unsigned char *) mxGetPr(prhs[0]);
N = mxGetM(prhs[0]) * mxGetN(prhs[0]);
//--
// OUTPUT
//--
// median
y = mxGetPr(plhs[0] = mxCreateDoubleMatrix(1,1,mxREAL));
//--
// COMPUTATION
//--
// buffer image
B8 = mxCalloc(N,sizeof(unsigned char));
for (k = 0; k < N; k++) {
*(B8 + k) = *(X8 + k);
}
// compute median
if (N % 2) {
*y = (double) median_uint8(B8,N);
} else {
*y = ((double) kth_smallest_uint8(B8,N,N/2 - 1) +
(double) kth_smallest_uint8(B8,N,N/2)) / 2.0;
}
} else {
//--
// INPUT
//--
// input image
X = mxGetPr(prhs[0]);
N = mxGetM(prhs[0]) * mxGetN(prhs[0]);
//--
// OUTPUT
//--
// median
y = mxGetPr(plhs[0] = mxCreateDoubleMatrix(1,1,mxREAL));
//--
// COMPUTATION
//--
// buffer image
B = mxCalloc(N,sizeof(double));
for (k = 0; k < N; k++) {
*(B + k) = *(X + k);
}
// compute median
if (N % 2) {
*y = median_double(B,N);
} else {
*y = (kth_smallest_double(B,N,N/2 - 1) + kth_smallest_double(B,N,N/2)) / 2.0;
}
}
}
/** Look through the routerlist, the Mean Time Between Failure history, and
* the Weighted Fractional Uptime history, and use them to set thresholds for
* the Stable, Fast, and Guard flags. Update the fields stable_uptime,
* stable_mtbf, enough_mtbf_info, guard_wfu, guard_tk, fast_bandwidth,
* guard_bandwidth_including_exits, and guard_bandwidth_excluding_exits.
*
* Also, set the is_exit flag of each router appropriately. */
void
dirserv_compute_performance_thresholds(digestmap_t *omit_as_sybil)
{
int n_active, n_active_nonexit, n_familiar;
uint32_t *uptimes, *bandwidths_kb, *bandwidths_excluding_exits_kb;
long *tks;
double *mtbfs, *wfus;
smartlist_t *nodelist;
time_t now = time(NULL);
const or_options_t *options = get_options();
/* Require mbw? */
int require_mbw =
(dirserv_get_last_n_measured_bws() >
options->MinMeasuredBWsForAuthToIgnoreAdvertised) ? 1 : 0;
/* initialize these all here, in case there are no routers */
stable_uptime = 0;
stable_mtbf = 0;
fast_bandwidth_kb = 0;
guard_bandwidth_including_exits_kb = 0;
guard_bandwidth_excluding_exits_kb = 0;
guard_tk = 0;
guard_wfu = 0;
nodelist_assert_ok();
nodelist = nodelist_get_list();
/* Initialize arrays that will hold values for each router. We'll
* sort them and use that to compute thresholds. */
n_active = n_active_nonexit = 0;
/* Uptime for every active router. */
uptimes = tor_calloc(smartlist_len(nodelist), sizeof(uint32_t));
/* Bandwidth for every active router. */
bandwidths_kb = tor_calloc(smartlist_len(nodelist), sizeof(uint32_t));
/* Bandwidth for every active non-exit router. */
bandwidths_excluding_exits_kb =
tor_calloc(smartlist_len(nodelist), sizeof(uint32_t));
/* Weighted mean time between failure for each active router. */
mtbfs = tor_calloc(smartlist_len(nodelist), sizeof(double));
/* Time-known for each active router. */
tks = tor_calloc(smartlist_len(nodelist), sizeof(long));
/* Weighted fractional uptime for each active router. */
wfus = tor_calloc(smartlist_len(nodelist), sizeof(double));
/* Now, fill in the arrays. */
SMARTLIST_FOREACH_BEGIN(nodelist, node_t *, node) {
if (options->BridgeAuthoritativeDir &&
node->ri &&
node->ri->purpose != ROUTER_PURPOSE_BRIDGE)
continue;
routerinfo_t *ri = node->ri;
if (ri) {
node->is_exit = (!router_exit_policy_rejects_all(ri) &&
exit_policy_is_general_exit(ri->exit_policy));
}
if (router_counts_toward_thresholds(node, now, omit_as_sybil,
require_mbw)) {
const char *id = node->identity;
uint32_t bw_kb;
/* resolve spurious clang shallow analysis null pointer errors */
tor_assert(ri);
uptimes[n_active] = (uint32_t)real_uptime(ri, now);
mtbfs[n_active] = rep_hist_get_stability(id, now);
tks [n_active] = rep_hist_get_weighted_time_known(id, now);
bandwidths_kb[n_active] = bw_kb = dirserv_get_credible_bandwidth_kb(ri);
if (!node->is_exit || node->is_bad_exit) {
bandwidths_excluding_exits_kb[n_active_nonexit] = bw_kb;
++n_active_nonexit;
}
++n_active;
}
} SMARTLIST_FOREACH_END(node);
/* Now, compute thresholds. */
if (n_active) {
/* The median uptime is stable. */
stable_uptime = median_uint32(uptimes, n_active);
/* The median mtbf is stable, if we have enough mtbf info */
stable_mtbf = median_double(mtbfs, n_active);
/* The 12.5th percentile bandwidth is fast. */
fast_bandwidth_kb = find_nth_uint32(bandwidths_kb, n_active, n_active/8);
/* (Now bandwidths is sorted.) */
if (fast_bandwidth_kb < RELAY_REQUIRED_MIN_BANDWIDTH/(2 * 1000))
fast_bandwidth_kb = bandwidths_kb[n_active/4];
guard_bandwidth_including_exits_kb =
third_quartile_uint32(bandwidths_kb, n_active);
guard_tk = find_nth_long(tks, n_active, n_active/8);
}
if (guard_tk > TIME_KNOWN_TO_GUARANTEE_FAMILIAR)
guard_tk = TIME_KNOWN_TO_GUARANTEE_FAMILIAR;
{
/* We can vote on a parameter for the minimum and maximum. */
#define ABSOLUTE_MIN_VALUE_FOR_FAST_FLAG 4
int32_t min_fast_kb, max_fast_kb, min_fast, max_fast;
min_fast = networkstatus_get_param(NULL, "FastFlagMinThreshold",
ABSOLUTE_MIN_VALUE_FOR_FAST_FLAG,
ABSOLUTE_MIN_VALUE_FOR_FAST_FLAG,
INT32_MAX);
if (options->TestingTorNetwork) {
min_fast = (int32_t)options->TestingMinFastFlagThreshold;
}
max_fast = networkstatus_get_param(NULL, "FastFlagMaxThreshold",
INT32_MAX, min_fast, INT32_MAX);
min_fast_kb = min_fast / 1000;
max_fast_kb = max_fast / 1000;
if (fast_bandwidth_kb < (uint32_t)min_fast_kb)
fast_bandwidth_kb = min_fast_kb;
if (fast_bandwidth_kb > (uint32_t)max_fast_kb)
fast_bandwidth_kb = max_fast_kb;
}
/* Protect sufficiently fast nodes from being pushed out of the set
* of Fast nodes. */
if (options->AuthDirFastGuarantee &&
fast_bandwidth_kb > options->AuthDirFastGuarantee/1000)
fast_bandwidth_kb = (uint32_t)options->AuthDirFastGuarantee/1000;
/* Now that we have a time-known that 7/8 routers are known longer than,
* fill wfus with the wfu of every such "familiar" router. */
n_familiar = 0;
SMARTLIST_FOREACH_BEGIN(nodelist, node_t *, node) {
if (router_counts_toward_thresholds(node, now,
omit_as_sybil, require_mbw)) {
routerinfo_t *ri = node->ri;
const char *id = ri->cache_info.identity_digest;
long tk = rep_hist_get_weighted_time_known(id, now);
if (tk < guard_tk)
continue;
wfus[n_familiar++] = rep_hist_get_weighted_fractional_uptime(id, now);
}
} SMARTLIST_FOREACH_END(node);
if (n_familiar)
guard_wfu = median_double(wfus, n_familiar);
if (guard_wfu > WFU_TO_GUARANTEE_GUARD)
guard_wfu = WFU_TO_GUARANTEE_GUARD;
enough_mtbf_info = rep_hist_have_measured_enough_stability();
if (n_active_nonexit) {
guard_bandwidth_excluding_exits_kb =
find_nth_uint32(bandwidths_excluding_exits_kb,
n_active_nonexit, n_active_nonexit*3/4);
}
log_info(LD_DIRSERV,
"Cutoffs: For Stable, %lu sec uptime, %lu sec MTBF. "
"For Fast: %lu kilobytes/sec. "
"For Guard: WFU %.03f%%, time-known %lu sec, "
"and bandwidth %lu or %lu kilobytes/sec. "
"We%s have enough stability data.",
(unsigned long)stable_uptime,
(unsigned long)stable_mtbf,
(unsigned long)fast_bandwidth_kb,
guard_wfu*100,
(unsigned long)guard_tk,
(unsigned long)guard_bandwidth_including_exits_kb,
(unsigned long)guard_bandwidth_excluding_exits_kb,
enough_mtbf_info ? "" : " don't");
tor_free(uptimes);
tor_free(mtbfs);
tor_free(bandwidths_kb);
tor_free(bandwidths_excluding_exits_kb);
tor_free(tks);
tor_free(wfus);
}
/** Run unit tests for getting the median of a list. */
static void
test_container_order_functions(void *arg)
{
int lst[25], n = 0;
uint32_t lst_2[25];
// int a=12,b=24,c=25,d=60,e=77;
#define median() median_int(lst, n)
(void)arg;
lst[n++] = 12;
tt_int_op(12,OP_EQ, median()); /* 12 */
lst[n++] = 77;
//smartlist_shuffle(sl);
tt_int_op(12,OP_EQ, median()); /* 12, 77 */
lst[n++] = 77;
//smartlist_shuffle(sl);
tt_int_op(77,OP_EQ, median()); /* 12, 77, 77 */
lst[n++] = 24;
tt_int_op(24,OP_EQ, median()); /* 12,24,77,77 */
lst[n++] = 60;
lst[n++] = 12;
lst[n++] = 25;
//smartlist_shuffle(sl);
tt_int_op(25,OP_EQ, median()); /* 12,12,24,25,60,77,77 */
#undef median
#define third_quartile() third_quartile_uint32(lst_2, n)
n = 0;
lst_2[n++] = 1;
tt_int_op(1,OP_EQ, third_quartile()); /* ~1~ */
lst_2[n++] = 2;
tt_int_op(2,OP_EQ, third_quartile()); /* 1, ~2~ */
lst_2[n++] = 3;
lst_2[n++] = 4;
lst_2[n++] = 5;
tt_int_op(4,OP_EQ, third_quartile()); /* 1, 2, 3, ~4~, 5 */
lst_2[n++] = 6;
lst_2[n++] = 7;
lst_2[n++] = 8;
lst_2[n++] = 9;
tt_int_op(7,OP_EQ, third_quartile()); /* 1, 2, 3, 4, 5, 6, ~7~, 8, 9 */
lst_2[n++] = 10;
lst_2[n++] = 11;
/* 1, 2, 3, 4, 5, 6, 7, 8, ~9~, 10, 11 */
tt_int_op(9,OP_EQ, third_quartile());
#undef third_quartile
double dbls[] = { 1.0, 10.0, 100.0, 1e4, 1e5, 1e6 };
tt_double_eq(1.0, median_double(dbls, 1));
tt_double_eq(1.0, median_double(dbls, 2));
tt_double_eq(10.0, median_double(dbls, 3));
tt_double_eq(10.0, median_double(dbls, 4));
tt_double_eq(100.0, median_double(dbls, 5));
tt_double_eq(100.0, median_double(dbls, 6));
time_t times[] = { 5, 10, 20, 25, 15 };
tt_assert(5 == median_time(times, 1));
tt_assert(5 == median_time(times, 2));
tt_assert(10 == median_time(times, 3));
tt_assert(10 == median_time(times, 4));
tt_assert(15 == median_time(times, 5));
int32_t int32s[] = { -5, -10, -50, 100 };
tt_int_op(-5, ==, median_int32(int32s, 1));
tt_int_op(-10, ==, median_int32(int32s, 2));
tt_int_op(-10, ==, median_int32(int32s, 3));
tt_int_op(-10, ==, median_int32(int32s, 4));
long longs[] = { -30, 30, 100, -100, 7 };
tt_int_op(7, ==, find_nth_long(longs, 5, 2));
done:
;
}
double median(int n, double *data)
{
return median_double(n, data);
}
