192 lines
8 KiB
C
192 lines
8 KiB
C
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/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/log.h"
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#include "libavutil/timer.h"
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#include "libavutil/lfg.h"
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static const double Z_TABLE[31][10] = {
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{0.5000, 0.5040, 0.5080, 0.5120, 0.5160, 0.5199, 0.5239, 0.5279, 0.5319, 0.5359},
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{0.5398, 0.5438, 0.5478, 0.5517, 0.5557, 0.5596, 0.5636, 0.5675, 0.5714, 0.5753},
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{0.5793, 0.5832, 0.5871, 0.5910, 0.5948, 0.5987, 0.6026, 0.6064, 0.6103, 0.6141},
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{0.6179, 0.6217, 0.6255, 0.6293, 0.6331, 0.6368, 0.6406, 0.6443, 0.6480, 0.6517},
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{0.6554, 0.6591, 0.6628, 0.6664, 0.6700, 0.6736, 0.6772, 0.6808, 0.6844, 0.6879},
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{0.6915, 0.6950, 0.6985, 0.7019, 0.7054, 0.7088, 0.7123, 0.7157, 0.7190, 0.7224},
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{0.7257, 0.7291, 0.7324, 0.7357, 0.7389, 0.7422, 0.7454, 0.7486, 0.7517, 0.7549},
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{0.7580, 0.7611, 0.7642, 0.7673, 0.7704, 0.7734, 0.7764, 0.7794, 0.7823, 0.7852},
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{0.7881, 0.7910, 0.7939, 0.7967, 0.7995, 0.8023, 0.8051, 0.8078, 0.8106, 0.8133},
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{0.8159, 0.8186, 0.8212, 0.8238, 0.8264, 0.8289, 0.8315, 0.8340, 0.8365, 0.8389},
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{0.8413, 0.8438, 0.8461, 0.8485, 0.8508, 0.8531, 0.8554, 0.8577, 0.8599, 0.8621},
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{0.8643, 0.8665, 0.8686, 0.8708, 0.8729, 0.8749, 0.8770, 0.8790, 0.8810, 0.8830},
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{0.8849, 0.8869, 0.8888, 0.8907, 0.8925, 0.8944, 0.8962, 0.8980, 0.8997, 0.9015},
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{0.9032, 0.9049, 0.9066, 0.9082, 0.9099, 0.9115, 0.9131, 0.9147, 0.9162, 0.9177},
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{0.9192, 0.9207, 0.9222, 0.9236, 0.9251, 0.9265, 0.9279, 0.9292, 0.9306, 0.9319},
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{0.9332, 0.9345, 0.9357, 0.9370, 0.9382, 0.9394, 0.9406, 0.9418, 0.9429, 0.9441},
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{0.9452, 0.9463, 0.9474, 0.9484, 0.9495, 0.9505, 0.9515, 0.9525, 0.9535, 0.9545},
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{0.9554, 0.9564, 0.9573, 0.9582, 0.9591, 0.9599, 0.9608, 0.9616, 0.9625, 0.9633},
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{0.9641, 0.9649, 0.9656, 0.9664, 0.9671, 0.9678, 0.9686, 0.9693, 0.9699, 0.9706},
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{0.9713, 0.9719, 0.9726, 0.9732, 0.9738, 0.9744, 0.9750, 0.9756, 0.9761, 0.9767},
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{0.9772, 0.9778, 0.9783, 0.9788, 0.9793, 0.9798, 0.9803, 0.9808, 0.9812, 0.9817},
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{0.9821, 0.9826, 0.9830, 0.9834, 0.9838, 0.9842, 0.9846, 0.9850, 0.9854, 0.9857},
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{0.9861, 0.9864, 0.9868, 0.9871, 0.9875, 0.9878, 0.9881, 0.9884, 0.9887, 0.9890},
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{0.9893, 0.9896, 0.9898, 0.9901, 0.9904, 0.9906, 0.9909, 0.9911, 0.9913, 0.9916},
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{0.9918, 0.9920, 0.9922, 0.9925, 0.9927, 0.9929, 0.9931, 0.9932, 0.9934, 0.9936},
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{0.9938, 0.9940, 0.9941, 0.9943, 0.9945, 0.9946, 0.9948, 0.9949, 0.9951, 0.9952},
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{0.9953, 0.9955, 0.9956, 0.9957, 0.9959, 0.9960, 0.9961, 0.9962, 0.9963, 0.9964},
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{0.9965, 0.9966, 0.9967, 0.9968, 0.9969, 0.9970, 0.9971, 0.9972, 0.9973, 0.9974},
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{0.9974, 0.9975, 0.9976, 0.9977, 0.9977, 0.9978, 0.9979, 0.9979, 0.9980, 0.9981},
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{0.9981, 0.9982, 0.9982, 0.9983, 0.9984, 0.9984, 0.9985, 0.9985, 0.9986, 0.9986},
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{0.9987, 0.9987, 0.9987, 0.9988, 0.9988, 0.9989, 0.9989, 0.9989, 0.9990, 0.9990} };
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// Inverse cumulative distribution function
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static double inv_cdf(double u)
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{
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const double a[4] = { 2.50662823884,
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-18.61500062529,
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41.39119773534,
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-25.44106049637};
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const double b[4] = {-8.47351093090,
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23.08336743743,
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-21.06224101826,
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3.13082909833};
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const double c[9] = {0.3374754822726147,
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0.9761690190917186,
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0.1607979714918209,
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0.0276438810333863,
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0.0038405729373609,
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0.0003951896511919,
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0.0000321767881768,
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0.0000002888167364,
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0.0000003960315187};
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double r;
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double x = u - 0.5;
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// Beasley-Springer
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if (fabs(x) < 0.42) {
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double y = x * x;
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r = x * (((a[3]*y+a[2])*y+a[1])*y+a[0]) /
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((((b[3]*y+b[2])*y+b[1])*y+b[0])*y+1.0);
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}
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else {// Moro
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r = u;
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if (x > 0.0)
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r = 1.0 - u;
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r = log(-log(r));
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r = c[0] + r*(c[1]+r*(c[2]+r*(c[3]+r*(c[4]+r*(c[5]+r*(c[6]+
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r*(c[7]+r*c[8])))))));
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if (x < 0.0)
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r = -r;
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}
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return r;
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}
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int main(void)
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{
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int x = 0;
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int i, j;
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AVLFG state;
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av_lfg_init(&state, 0xdeadbeef);
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for (j = 0; j < 10000; j++) {
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for (i = 0; i < 624; i++) {
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//av_log(NULL, AV_LOG_ERROR, "%X\n", av_lfg_get(&state));
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x += av_lfg_get(&state);
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}
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}
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av_log(NULL, AV_LOG_ERROR, "final value:%X\n", x);
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/* BMG usage example */
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{
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double mean = 1000;
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double stddev = 53;
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double samp_mean = 0.0, samp_stddev = 0.0, QH = 0;
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double Z, p_value = -1, tot_samp = 1000;
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double *PRN_arr = av_malloc_array(tot_samp, sizeof(double));
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if (!PRN_arr) {
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fprintf(stderr, "failed to allocate memory!\n");
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return 1;
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}
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av_lfg_init(&state, 42);
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for (i = 0; i < tot_samp; i += 2) {
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double bmg_out[2];
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av_bmg_get(&state, bmg_out);
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PRN_arr[i ] = bmg_out[0] * stddev + mean;
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PRN_arr[i+1] = bmg_out[1] * stddev + mean;
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samp_mean += PRN_arr[i] + PRN_arr[i+1];
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samp_stddev += PRN_arr[i] * PRN_arr[i] + PRN_arr[i+1] * PRN_arr[i+1];
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printf("PRN%d : %f\n"
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"PRN%d : %f\n",
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i, PRN_arr[i], i+1, PRN_arr[i+1]);
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}
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samp_mean /= tot_samp;
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samp_stddev /= (tot_samp - 1);
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samp_stddev -= (tot_samp * 1.0 / (tot_samp - 1))*samp_mean*samp_mean;
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samp_stddev = sqrt(samp_stddev);
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Z = (mean - samp_mean) / (stddev / sqrt(tot_samp));
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{
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int x, y, a, b, flag = 0;
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if (Z < 0.0) {
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flag = !flag;
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Z = Z * -1.0;
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}
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a = (int)(Z * 100);
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b = ((int)Z * 100);
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x = Z * 10;
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y = (b > 0) ? a % b : a;
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y = y % 10;
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if (x > 30 || y > 9) {
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av_log(NULL, AV_LOG_INFO, "error: out of bounds! tried to access"
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"Z_TABLE[%d][%d]\n", x, y);
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goto SKIP;
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}
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p_value = flag ? 1 - Z_TABLE[x][y] : Z_TABLE[x][y];
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}
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SKIP: for (i = 0; i < tot_samp; ++i) {
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if ( i < (tot_samp - 1)) {
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double H_diff;
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H_diff = inv_cdf((i + 2.0 - (3.0/8.0)) / (tot_samp + (1.0/4.0)));
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H_diff -= inv_cdf((i + 1.0 - (3.0/8.0)) / (tot_samp + (1.0/4.0)));
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QH += ((PRN_arr[i + 1] - PRN_arr[i]) / H_diff);
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}
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}
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QH = 1.0 - QH / ((tot_samp - 1.0) * samp_stddev);
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printf("sample mean : %f\n"
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"true mean : %f\n"
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"sample stddev: %f\n"
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"true stddev : %f\n"
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"z-score : %f\n"
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"p-value : %f\n"
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"QH[normality]: %f\n",
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samp_mean, mean, samp_stddev, stddev, Z, p_value, QH);
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av_freep(&PRN_arr);
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}
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return 0;
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}
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