113 lines
2.9 KiB
PHP
113 lines
2.9 KiB
PHP
<?php
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declare(strict_types=1);
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namespace Phpml\SupportVectorMachine;
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use Phpml\Exception\InvalidArgumentException;
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class DataTransformer
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{
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public static function trainingSet(array $samples, array $labels, bool $targets = false): string
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{
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$set = '';
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$numericLabels = [];
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if (!$targets) {
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$numericLabels = self::numericLabels($labels);
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}
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foreach ($labels as $index => $label) {
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$set .= sprintf('%s %s %s', ($targets ? $label : $numericLabels[$label]), self::sampleRow($samples[$index]), PHP_EOL);
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}
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return $set;
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}
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public static function testSet(array $samples): string
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{
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if (count($samples) === 0) {
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throw new InvalidArgumentException('The array has zero elements');
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}
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if (!is_array($samples[0])) {
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$samples = [$samples];
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}
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$set = '';
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foreach ($samples as $sample) {
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$set .= sprintf('0 %s %s', self::sampleRow($sample), PHP_EOL);
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}
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return $set;
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}
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public static function predictions(string $rawPredictions, array $labels): array
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{
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$numericLabels = self::numericLabels($labels);
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$results = [];
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foreach (explode(PHP_EOL, $rawPredictions) as $result) {
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if (isset($result[0])) {
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$results[] = array_search((int) $result, $numericLabels, true);
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}
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}
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return $results;
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}
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public static function probabilities(string $rawPredictions, array $labels): array
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{
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$numericLabels = self::numericLabels($labels);
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$predictions = explode(PHP_EOL, trim($rawPredictions));
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$header = array_shift($predictions);
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$headerColumns = explode(' ', (string) $header);
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array_shift($headerColumns);
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$columnLabels = [];
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foreach ($headerColumns as $numericLabel) {
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$columnLabels[] = array_search((int) $numericLabel, $numericLabels, true);
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}
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$results = [];
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foreach ($predictions as $rawResult) {
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$probabilities = explode(' ', $rawResult);
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array_shift($probabilities);
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$result = [];
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foreach ($probabilities as $i => $prob) {
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$result[$columnLabels[$i]] = (float) $prob;
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}
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$results[] = $result;
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}
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return $results;
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}
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public static function numericLabels(array $labels): array
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{
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$numericLabels = [];
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foreach ($labels as $label) {
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if (isset($numericLabels[$label])) {
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continue;
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}
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$numericLabels[$label] = count($numericLabels);
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}
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return $numericLabels;
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}
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private static function sampleRow(array $sample): string
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{
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$row = [];
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foreach ($sample as $index => $feature) {
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$row[] = sprintf('%s:%F', $index + 1, $feature);
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}
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return implode(' ', $row);
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}
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}
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