From f24fd147184ba6b2c6a6cb41aad1fa861f000486 Mon Sep 17 00:00:00 2001
From: Gilles Sadowski <gilleseran@gmail.com>
Date: Mon, 31 May 2021 03:47:57 +0200
Subject: [PATCH] MATH-1596: Removed dependency on "RandomVectorGenerator".

---
 .../random/CorrelatedRandomVectorGenerator.java     | 13 ++++++-------
 .../random/CorrelatedRandomVectorGeneratorTest.java |  6 +++---
 .../regression/GLSMultipleLinearRegressionTest.java |  2 +-
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/random/CorrelatedRandomVectorGenerator.java b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/random/CorrelatedRandomVectorGenerator.java
index 0338f5f38..789c05aad 100644
--- a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/random/CorrelatedRandomVectorGenerator.java
+++ b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/random/CorrelatedRandomVectorGenerator.java
@@ -17,13 +17,15 @@
 
 package org.apache.commons.math4.legacy.random;
 
+import java.util.function.Supplier;
+
 import org.apache.commons.math4.legacy.exception.DimensionMismatchException;
 import org.apache.commons.math4.legacy.linear.RealMatrix;
 import org.apache.commons.math4.legacy.linear.RectangularCholeskyDecomposition;
 
 /**
- * A {@link RandomVectorGenerator} that generates vectors with with
- * correlated components.
+ * Generates vectors with with correlated components.
+ *
  * <p>Random vectors with correlated components are built by combining
  * the uncorrelated components of another random vector in such a way that
  * the resulting correlations are the ones specified by a positive
@@ -57,8 +59,7 @@ import org.apache.commons.math4.legacy.linear.RectangularCholeskyDecomposition;
  * @since 1.2
  */
 
-public class CorrelatedRandomVectorGenerator
-    implements RandomVectorGenerator {
+public class CorrelatedRandomVectorGenerator implements Supplier<double[]> {
     /** Mean vector. */
     private final double[] mean;
     /** Underlying generator. */
@@ -162,8 +163,7 @@ public class CorrelatedRandomVectorGenerator
      * is created at each call, the caller can do what it wants with it.
      */
     @Override
-    public double[] nextVector() {
-
+    public double[] get() {
         // generate uncorrelated vector
         for (int i = 0; i < normalized.length; ++i) {
             normalized[i] = generator.nextNormalizedDouble();
@@ -181,5 +181,4 @@ public class CorrelatedRandomVectorGenerator
         return correlated;
 
     }
-
 }
diff --git a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/CorrelatedRandomVectorGeneratorTest.java b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/CorrelatedRandomVectorGeneratorTest.java
index 273e12638..1010c6476 100644
--- a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/CorrelatedRandomVectorGeneratorTest.java
+++ b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/random/CorrelatedRandomVectorGeneratorTest.java
@@ -89,7 +89,7 @@ public class CorrelatedRandomVectorGeneratorTest {
         double[] max = new double[mean.length];
         Arrays.fill(max, Double.NEGATIVE_INFINITY);
         for (int i = 0; i < 10; i++) {
-            double[] generated = sg.nextVector();
+            double[] generated = sg.get();
             for (int j = 0; j < generated.length; ++j) {
                 min[j] = FastMath.min(min[j], generated[j]);
                 max[j] = FastMath.max(max[j], generated[j]);
@@ -118,7 +118,7 @@ public class CorrelatedRandomVectorGeneratorTest {
         VectorialMean meanStat = new VectorialMean(mean.length);
         VectorialCovariance covStat = new VectorialCovariance(mean.length, true);
         for (int i = 0; i < 5000; ++i) {
-            double[] v = generator.nextVector();
+            double[] v = generator.get();
             meanStat.increment(v);
             covStat.increment(v);
         }
@@ -181,7 +181,7 @@ public class CorrelatedRandomVectorGeneratorTest {
 
         StorelessCovariance cov = new StorelessCovariance(covMatrix.length);
         for (int i = 0; i < samples; ++i) {
-            cov.increment(sampler.nextVector());
+            cov.increment(sampler.get());
         }
 
         double[][] sampleCov = cov.getData();
diff --git a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/regression/GLSMultipleLinearRegressionTest.java b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/regression/GLSMultipleLinearRegressionTest.java
index f507be2eb..0e7bf3ffa 100644
--- a/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/regression/GLSMultipleLinearRegressionTest.java
+++ b/commons-math-legacy/src/test/java/org/apache/commons/math4/legacy/stat/regression/GLSMultipleLinearRegressionTest.java
@@ -276,7 +276,7 @@ public class GLSMultipleLinearRegressionTest extends MultipleLinearRegressionAbs
         for (int i = 0; i < nModels; i++) {
 
             // Generate y = xb + u with u cov
-            RealVector u = MatrixUtils.createRealVector(gen.nextVector());
+            RealVector u = MatrixUtils.createRealVector(gen.get());
             double[] y = u.add(x.operate(b)).toArray();
 
             // Estimate OLS parameters