weibozhao commented on a change in pull request #24: URL: https://github.com/apache/flink-ml/pull/24#discussion_r765500552
########## File path: flink-ml-core/src/main/java/org/apache/flink/ml/linalg/BLAS.java ########## @@ -0,0 +1,97 @@ +/* + * 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.linalg; + +import org.apache.flink.util.Preconditions; + +/** A utility class that provides BLAS routines over matrices and vectors. */ +public class BLAS { + + private static final dev.ludovic.netlib.BLAS NATIVE_BLAS = + dev.ludovic.netlib.BLAS.getInstance(); + + /** + * \sum_i |x_i| . + * + * @param x x + * @return \sum_i |x_i| + */ + public static double asum(DenseVector x) { + return NATIVE_BLAS.dasum(x.size(), x.values, 0, 1); + } + + /** + * y += a * x . + * + * @param a a + * @param x x + * @param y y + */ + public static void axpy(double a, DenseVector x, DenseVector y) { + Preconditions.checkArgument(x.size() == y.size(), "Array dimension mismatched."); + NATIVE_BLAS.daxpy(x.size(), a, x.values, 1, y.values, 1); + } + + /** + * x \cdot y . + * + * @param x x + * @param y y + * @return x \cdot y + */ + public static double dot(DenseVector x, DenseVector y) { + Preconditions.checkArgument(x.size() == y.size(), "Array dimension mismatched."); + return NATIVE_BLAS.ddot(x.size(), x.values, 1, y.values, 1); + } + + /** + * \sqrt(\sum_i x_i * x_i) . + * + * @param x x + * @return \sqrt(\sum_i x_i * x_i) + */ + public static double norm2(DenseVector x) { + return NATIVE_BLAS.dnrm2(x.size(), x.values, 1); + } + + /** + * x = x * a . + * + * @param a a + * @param x x + */ + public static void scal(double a, DenseVector x) { + NATIVE_BLAS.dscal(x.size(), a, x.values, 1); + } + + /** y := alpha * A * x + beta * y . */ Review comment: OK -- 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. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
