34 lines
867 B
PHP
34 lines
867 B
PHP
<?php
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if (!function_exists('checkUserId')) {
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function checkUserId($client_id): bool
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{
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return \auth()->hasUser() && !is_null($client_id);
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}
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}
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if (!function_exists('stats_standard_deviation')) {
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function stats_standard_deviation(array $a, $sample = false): float|bool
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{
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$n = count($a);
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if ($n === 0) {
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trigger_error("The array has zero elements", E_USER_WARNING);
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return false;
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}
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if ($sample && $n === 1) {
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trigger_error("The array has only 1 element", E_USER_WARNING);
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return false;
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}
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$mean = array_sum($a) / $n;
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$carry = 0.0;
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foreach ($a as $val) {
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$d = ((double)$val) - $mean;
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$carry += $d * $d;
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};
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if ($sample) {
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--$n;
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}
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return sqrt($carry / $n);
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}
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}
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