ex00 commented on a change in pull request #8631: [FLINK-12745][ml] add sparse and dense vector class, and dense matrix class with basic operations. URL: https://github.com/apache/flink/pull/8631#discussion_r312855074
########## File path: flink-ml-parent/flink-ml-lib/src/main/java/org/apache/flink/ml/common/linalg/Vector.java ########## @@ -0,0 +1,159 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.flink.ml.common.linalg; + +import org.apache.commons.lang3.StringUtils; + +import java.io.Serializable; + +/** + * The Vector class defines some common methods for both DenseVector and + * SparseVector. + */ +public abstract class Vector implements Serializable { + /** + * Get the size of the vector. + */ + public abstract int size(); + + /** + * Get the i-th element of the vector. + */ + public abstract double get(int i); + + /** + * Set the i-th element of the vector to value "val". + */ + public abstract void set(int i, double val); + + /** + * Add the i-th element of the vector by value "val". + */ + public abstract void add(int i, double val); + + /** + * Return the L1 norm of the vector. + */ + public abstract double normL1(); + + /** + * Return the Inf norm of the vector. + */ + public abstract double normInf(); + + /** + * Return the L2 norm of the vector. + */ + public abstract double normL2(); + + /** + * Return the square of L2 norm of the vector. + */ + public abstract double normL2Square(); + + /** + * Scale the vector by value "v" and create a new vector to store the result. + */ + public abstract Vector scale(double v); + + /** + * Scale the vector by value "v". + */ + public abstract void scaleEqual(double v); + + /** + * Normalize the vector. + */ + public abstract void normalizeEqual(double p); + + /** + * Standardize the vector. + */ + public abstract void standardizeEqual(double mean, double stdvar); + + /** + * Create a new vector by adding an element to the head of the vector. + */ + public abstract Vector prefix(double v); + + /** + * Create a new vector by adding an element to the end of the vector. + */ + public abstract Vector append(double v); + + /** + * Create a new vector by plussing another vector. + */ + public abstract Vector plus(Vector vec); + + /** + * Create a new vector by subtracting another vector. + */ + public abstract Vector minus(Vector vec); + + /** + * Compute the dot product with another vector. + */ + public abstract double dot(Vector vec); + + /** + * Get the iterator of the vector. + */ + public abstract VectorIterator iterator(); + + /** + * Serialize the vector to a string. + */ + public abstract String serialize(); + + /** + * Slice the vector. + */ + public abstract Vector slice(int[] indexes); + + /** + * Compute the outer product with itself. + * + * @return The outer product matrix. + */ + public abstract DenseMatrix outer(); + + /** + * Parse either a {@link SparseVector} or a {@link DenseVector} from a formatted string. + * + * <p>The format of a dense vector is comma separated values such as "1 2 3 4". + * The format of a sparse vector is comma separated index-value pairs, such as "0:1 2:3 3:4". + * If the sparse vector has determined vector size, the size is prepended to the head. For example, + * the string "$4$0:1 2:3 3:4" represents a sparse vector with size 4. + * + * @param str A formatted string representing a vector. + * @return The parsed vector. + */ + public static Vector parse(String str) { + boolean isSparse = org.apache.flink.util.StringUtils.isNullOrWhitespaceOnly(str) + || StringUtils.indexOf(str, SparseVector.INDEX_VALUE_DELIMITER) != -1 + || StringUtils.indexOf(str, SparseVector.HEADER_DELIMITER) != -1; + if (isSparse) { + return SparseVector.deserialize(str); Review comment: Please do not use child classes in the parent class. The circular dependency is not good practice. I suggest renaming this method to `deserialize` and keep implementation in child classes only. Or move this method to some util class. Also I assume `SparseVector` also can parse dense vector and store it as sparse. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
