DVDoug\BoxPacker\Packer::setItems PHP Method

    public function setItems($items)
    {
        if ($items instanceof ItemList) {
            $this->items = clone $items;
        } else {
            $this->items = new ItemList();
            foreach ($items as $item) {
                $this->items->insert($item);
            }
        }
    }

 /**
  * Given a solution set of packed boxes, repack them to achieve optimum weight distribution
  *
  * @param PackedBoxList $aPackedBoxes
  * @return PackedBoxList
  */
 public function redistributeWeight(PackedBoxList $aPackedBoxes)
 {
     $targetWeight = $aPackedBoxes->getMeanWeight();
     $this->logger->log(LogLevel::DEBUG, "repacking for weight distribution, weight variance {$aPackedBoxes->getWeightVariance()}, target weight {$targetWeight}");
     $packedBoxes = new PackedBoxList();
     $overWeightBoxes = [];
     $underWeightBoxes = [];
     foreach ($aPackedBoxes as $packedBox) {
         $boxWeight = $packedBox->getWeight();
         if ($boxWeight > $targetWeight) {
             $overWeightBoxes[] = $packedBox;
         } else {
             if ($boxWeight < $targetWeight) {
                 $underWeightBoxes[] = $packedBox;
             } else {
                 $packedBoxes->insert($packedBox);
                 //target weight, so we'll keep these
             }
         }
     }
     do {
         //Keep moving items from most overweight box to most underweight box
         $tryRepack = false;
         $this->logger->log(LogLevel::DEBUG, 'boxes under/over target: ' . count($underWeightBoxes) . '/' . count($overWeightBoxes));
         foreach ($underWeightBoxes as $u => $underWeightBox) {
             foreach ($overWeightBoxes as $o => $overWeightBox) {
                 $overWeightBoxItems = $overWeightBox->getItems()->asArray();
                 //For each item in the heavier box, try and move it to the lighter one
                 foreach ($overWeightBoxItems as $oi => $overWeightBoxItem) {
                     if ($underWeightBox->getWeight() + $overWeightBoxItem->getWeight() > $targetWeight) {
                         continue;
                         //skip if moving this item would hinder rather than help weight distribution
                     }
                     $newItemsForLighterBox = clone $underWeightBox->getItems();
                     $newItemsForLighterBox->insert($overWeightBoxItem);
                     $newLighterBoxPacker = new Packer();
                     //we may need a bigger box
                     $newLighterBoxPacker->setBoxes($this->boxes);
                     $newLighterBoxPacker->setItems($newItemsForLighterBox);
                     $newLighterBox = $newLighterBoxPacker->doVolumePacking()->extract();
                     if ($newLighterBox->getItems()->count() === $newItemsForLighterBox->count()) {
                         //new item fits
                         unset($overWeightBoxItems[$oi]);
                         //now packed in different box
                         $newHeavierBoxPacker = new Packer();
                         //we may be able to use a smaller box
                         $newHeavierBoxPacker->setBoxes($this->boxes);
                         $newHeavierBoxPacker->setItems($overWeightBoxItems);
                         $overWeightBoxes[$o] = $newHeavierBoxPacker->doVolumePacking()->extract();
                         $underWeightBoxes[$u] = $newLighterBox;
                         $tryRepack = true;
                         //we did some work, so see if we can do even better
                         usort($overWeightBoxes, [$packedBoxes, 'reverseCompare']);
                         usort($underWeightBoxes, [$packedBoxes, 'reverseCompare']);
                         break 3;
                     }
                 }
             }
         }
     } while ($tryRepack);
     //Combine back into a single list
     $packedBoxes->insertFromArray($overWeightBoxes);
     $packedBoxes->insertFromArray($underWeightBoxes);
     return $packedBoxes;
 }