weibozhao commented on a change in pull request #24:
URL: https://github.com/apache/flink-ml/pull/24#discussion_r767395937
##########
File path: flink-ml-core/src/main/java/org/apache/flink/ml/linalg/BLAS.java
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@@ -22,13 +22,84 @@
/** A utility class that provides BLAS routines over matrices and vectors. */
public class BLAS {
+
/** For level-1 function dspmv, use javaBLAS for better performance. */
private static final dev.ludovic.netlib.BLAS JAVA_BLAS =
dev.ludovic.netlib.JavaBLAS.getInstance();
- /** y += a * x . */
+ /**
+ * \sum_i |x_i| .
+ *
+ * @param x x
+ * @return \sum_i |x_i|
+ */
+ public static double asum(DenseVector x) {
+ return JAVA_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(), "Vector size
mismatched.");
JAVA_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(), "Vector size
mismatched.");
+ return JAVA_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 JAVA_BLAS.dnrm2(x.size(), x.values, 1);
+ }
+
+ /**
+ * x = x * a .
+ *
+ * @param a a
+ * @param x x
+ */
+ public static void scal(double a, DenseVector x) {
+ JAVA_BLAS.dscal(x.size(), a, x.values, 1);
+ }
+
+ /**
+ * y := alpha * A * x + beta * y.
+ *
+ * @param matA m x n matrix A.
+ * @param transA transform matrix or not.
+ * @param x dense vector with size n.
+ * @param y dense vector with size m.
+ */
+ public static void gemv(
Review comment:
OK
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