create matrix array from users

    function get_matrix( $depths ) {
        $all_users = $this->get_all_users();
        $depths = [3, 3, 3];
        $matrix = [];

        for ( $level = 0; $level < count( $depths ); $level++ ) {
            $total_members = pow( $depths[$level], $level + 1 );
            $members = json_decode( json_encode( array_splice( $all_users, 0, $total_members ), JSON_FORCE_OBJECT ) );
            $members_arr = json_decode( json_encode( $members ), TRUE );
            $iter = new RecursiveIteratorIterator( new RecursiveArrayIterator( $members ), RecursiveIteratorIterator::SELF_FIRST );

            while ( $iter->valid() ) {
                $arr_depth = $iter->getDepth();
                $iterator_arr = $iter->getSubIterator( $arr_depth )->getArrayCopy();

                if ( pow( $depths[$level], $level ) == 1 && empty( $matrix ) ) {
                    $matrix[] = $iterator_arr;
                    break;
                }

                if ( !empty( $matrix ) && $level > 0 ) {
                    // $matrix_arr = json_decode( json_encode( $matrix, JSON_FORCE_OBJECT ) );
                    $matrix_arr = new ArrayObject( $matrix );
                    $miter = new RecursiveIteratorIterator( new RecursiveArrayIterator( $matrix_arr ), RecursiveIteratorIterator::SELF_FIRST );
                    while ( $miter->valid() ) {
                        $mdepth = $miter->getDepth();
                        $mkey = $miter->key();
                        $mval = $miter->current();
                        $marr = $miter->getInnerIterator()->getArrayCopy();

                        if ( $level == 1 && $mdepth == 1 ) {
                            $user['id'] = $mval;
                            $user['children'] = array_splice( $members_arr, 0, 3 );
                            $this->loop( $user, $miter );

                            for ( $msub = $mdepth; $msub >= 0; $msub-- ) {
                                $subIterator = $miter->getSubIterator( $msub );
                                $sub_arr = $subIterator->getArrayCopy();
                                $sub_val = $subIterator->current();
                                $sub_key = $subIterator->key();
                                if ( $msub == $mdepth ) {
                                    $subIterator->offsetSet( $sub_key, $user );
                                } else {
                                    $parent_arr_copy = $miter->getSubIterator( $msub + 1 )->getArrayCopy();
                                    $subIterator->offsetSet( $sub_key, $parent_arr_copy );
                                }
                            }
                        }

                        if ( $level >= 2 && $mdepth > $level && $mdepth <= count( $depths ) ) {
                            $user['id'] = $mval;
                            $user['children'] = array_splice( $members_arr, 0, 3 );
                            for ( $msub = $mdepth; $msub >= 0; $msub-- ) {
                                $subIterator = $miter->getSubIterator( $msub );
                                $sub_arr = $subIterator->getArrayCopy();
                                $sub_val = $subIterator->current();
                                $sub_key = $subIterator->key();
                                if ( $msub == $mdepth ) {
                                    $subIterator->offsetSet( $sub_key, $user );
                                } else {
                                    $parent_arr_copy = $miter->getSubIterator( $msub + 1 )->getArrayCopy();
                                    $subIterator->offsetSet( $sub_key, $parent_arr_copy );
                                }
                            }
                        }

                        if ( empty( $members_arr ) ) {
                            $matrix = json_decode( json_encode( $matrix_arr, JSON_FORCE_OBJECT ), TRUE );
                            break 2;
                        }

                        if ( $mdepth > $level && $level == 1 ) {
                            $matrix = json_decode( json_encode( $matrix_arr, JSON_FORCE_OBJECT ), TRUE );
                            break;
                        }

                        if ( ($mdepth > $level && $mdepth > count( $depths ) ) && $level != 1 ) {
                            $matrix = json_decode( json_encode( $matrix_arr, JSON_FORCE_OBJECT ), TRUE );
                            break;
                        }

                        $miter->next();
                    }
                }
                $iter->next();
            }
        }

        return $matrix;
    }