4 results about "Quicksort algorithm" patented technology

This invention provides a method, apparatus, and vehicle for constructing a KD-tree from a vehicle-mounted LiDAR point cloud. The method includes: determining the first median of the point cloud data; performing KD-tree construction steps based on the left and right interval data until the unprocessed data variable is 0, and outputting the KD-tree. Thus, by obtaining the median using a quicksort algorithm, a full sort of the point cloud data is not required. Instead, the data is partitioned into two parts: less than a benchmark value and greater than a benchmark value. The median is then recursively searched, improving the efficiency of finding the first median. Since the first median divides the point cloud data into independent left and right interval data, multi-threaded parallel searching of left and right subtree nodes can be used during KD-tree construction, thereby improving the efficiency of KD-tree construction for the vehicle-mounted LiDAR point cloud and ensuring the response speed and operational sensitivity of the autonomous driving system.

The invention discloses a zero point measuring device of a Coriolis flowmeter and a zero point error compensation method. The device comprises a constant-temperature water tank, a heat preservation tank, a heater, an iron support, electric control ball valves, a Coriolis flow meter, a pipeline supporting frame, a variable-diameter clamping sleeve and an upper computer, and the zero point measurement and error compensation principle is that the upper computer issues a command to control opening and closing of the upstream electric control ball valve and the downstream electric control ball valve in a time-sharing mode, and after it is ensured that pipeline fluid is in a static state, the pipeline fluid is subjected to zero point measurement and error compensation. At the moment, the instantaneous flow collected by the flow meter is a zero value, N zero values are continuously collected according to the set sampling frequency f, the zero values are arranged in an ascending order through a rapid sorting algorithm, then zero correction is conducted through a median value average filtering algorithm, and therefore the compensated zero value Q0 of the Coriolis flow meter is obtained; and zero error compensation is carried out on the instantaneous flow Q1 and the accumulated flow Qm in the T time period. According to the method, the zero point of the Coriolis flowmeter is measured and the zero point error is corrected in a pure software mode, manual participation is not needed, and the zero point measurement efficiency and the flow measurement precision are improved.

The invention discloses a multi-dimensional data sorting method and device based on a chain comparator and a medium. The method comprises the steps that a to-be-sorted data set and a dimension parameter sequence are received; the dimension parameter sequence comprises a plurality of dimension identifiers arranged according to a priority order; analyzing the dimension parameter sequence, generating an attribute extraction logic chain corresponding to the dimension identifiers, and sequentially connecting the single-dimensional comparators corresponding to the dimension identifiers in series based on the attribute extraction logic chain so as to construct a chain type comparator; performing sorting operation on the to-be-sorted data set through a quick sorting algorithm; according to the quick sorting algorithm, a chain comparator is called to perform multi-dimensional data element comparison; and verifying whether the data dimension sequence in the sorting result accords with the priority sequence of the dimension sequence or not, and outputting a corresponding verification result.