Fixed Vector linspace precision

Author: andrewdalpino

CHANGELOG.md

@@ -1,5 +1,6 @@
-- Unreleased
-    - Changed percentile method changed to quantile
+- 2.0.5
+    - Percentile method changed to quantile
+    - Fixed Vector linspace precision
 
 - 2.0.4
     - Individual Arithmetic and Comparison methods now public

ext/include/conversion.c

@@ -0,0 +1,16 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "php.h"
+#include "kernel/operators.h"
+
+void hashmap_to_c_array(zval *return_value, zval *values)
+{
+    zval *current;
+    zend_ulong index;
+
+    ZEND_HASH_FOREACH_NUM_KEY_VAL(Z_ARRVAL_P(values), index, current) {
+
+    }
+}

src/Vector.php

@@ -242,26 +242,34 @@ public static function range($start, $end, $interval = 1) : self
     }
 
     /**
-     * Return evenly spaced numbers over a specified interval.
+     * Return n evenly spaced numbers between minimum and maximum.
      *
-     * @param float $start
-     * @param float $end
+     * @param float $min
+     * @param float $max
      * @param int $n
      * @throws \InvalidArgumentException
      * @return self
      */
-    public static function linspace(float $start, float $end, int $n) : self
+    public static function linspace(float $min, float $max, int $n) : self
     {
-        if ($n < 1) {
-            throw new InvalidArgumentException('The number of elements'
-                . " must be greater than 0, $n given.");
+        if ($n < 2) {
+            throw new InvalidArgumentException('Number of elements'
+                . " must be greater than 1, $n given.");
         }
 
-        $range = abs($end - $start);
+        $k = $n - 1;
+
+        $interval = abs($max - $min) / $k;
+
+        $a = [$min];
+
+        while (count($a) < $k) {
+            $a[] = end($a) + $interval;
+        }
 
-        $interval = ($range / ($n - 1)) - (EPSILON * $range);
+        $a[] = $max;
 
-        return static::range($start, $end, $interval);
+        return self::quick($a);
     }
 
     /**

tests/VectorTest.php

@@ -158,9 +158,9 @@ public function uniform() : void
      */
     public function range() : void
     {
-        $z = Vector::range(5.0, 12.0, 2.);
+        $z = Vector::range(5.0, 12.0, 2.0);
 
-        $expected = [5.0, 7.0, 9.0, 11.];
+        $expected = [5.0, 7.0, 9.0, 11.0];
 
         $this->assertInstanceOf(Vector::class, $z);
         $this->assertEquals($expected, $z->asArray());
@@ -171,15 +171,15 @@ public function range() : void
      */
     public function linspace() : void
     {
-        $z = Vector::linspace(-5, 5, 9);
+        $z = Vector::linspace(-5, 5, 10);
 
         $expected = [
-            -5.0, -3.7500001000000003, -2.5000002, -1.2500003, -4.0000000023354687E-7,
-            1.2499994999999995, 2.4999994, 3.749999299999999, 4.9999991999999995,
+            -5.0, -3.888888888888889, -2.7777777777777777, -1.6666666666666665, -0.5555555555555554,
+            0.5555555555555558, 1.666666666666667, 2.777777777777778, 3.8888888888888893, 5.0,
         ];
 
         $this->assertInstanceOf(Vector::class, $z);
-        $this->assertCount(9, $z);
+        $this->assertCount(10, $z);
         $this->assertEquals($expected, $z->asArray());
     }