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| author | Anton Luka Šijanec <anton@sijanec.eu> | 2022-01-11 12:35:47 +0100 |
|---|---|---|
| committer | Anton Luka Šijanec <anton@sijanec.eu> | 2022-01-11 12:35:47 +0100 |
| commit | 19985dbb8c0aa66dc4bf7905abc1148de909097d (patch) | |
| tree | 2cd5a5d20d7e80fc2a51adf60d838d8a2c40999e /admin/survey/excel/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php | |
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Diffstat (limited to 'admin/survey/excel/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php')
| -rw-r--r-- | admin/survey/excel/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/admin/survey/excel/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php b/admin/survey/excel/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php new file mode 100644 index 0000000..27c8937 --- /dev/null +++ b/admin/survey/excel/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php @@ -0,0 +1,59 @@ +<?php
+
+require_once "../Matrix.php";
+
+/**
+ * Given n points (x0,y0)...(xn-1,yn-1), the following methid computes
+ * the polynomial factors of the n-1't degree polynomial passing through
+ * the n points.
+ *
+ * Example: Passing in three points (2,3) (1,4) and (3,7) will produce
+ * the results [2.5, -8.5, 10] which means that the points are on the
+ * curve y = 2.5x² - 8.5x + 10.
+ *
+ * @see http://geosoft.no/software/lagrange/LagrangeInterpolation.java.html
+ * @author Jacob Dreyer
+ * @author Paul Meagher (port to PHP and minor changes)
+ *
+ * @param x[] float
+ * @param y[] float
+ */
+class LagrangeInterpolation {
+
+ public function findPolynomialFactors($x, $y) {
+ $n = count($x);
+
+ $data = array(); // double[n][n];
+ $rhs = array(); // double[n];
+
+ for ($i = 0; $i < $n; ++$i) {
+ $v = 1;
+ for ($j = 0; $j < $n; ++$j) {
+ $data[$i][$n-$j-1] = $v;
+ $v *= $x[$i];
+ }
+ $rhs[$i] = $y[$i];
+ }
+
+ // Solve m * s = b
+ $m = new Matrix($data);
+ $b = new Matrix($rhs, $n);
+
+ $s = $m->solve($b);
+
+ return $s->getRowPackedCopy();
+ } // function findPolynomialFactors()
+
+} // class LagrangeInterpolation
+
+
+$x = array(2.0, 1.0, 3.0);
+$y = array(3.0, 4.0, 7.0);
+
+$li = new LagrangeInterpolation;
+$f = $li->findPolynomialFactors($x, $y);
+
+
+for ($i = 0; $i < 3; ++$i) {
+ echo $f[$i]."<br />";
+}
|