From 27eab001af295008ed09ece35e4663cd21bf8fa9 Mon Sep 17 00:00:00 2001
From: zhengruifeng <ruifengz@foxmail.com>
Date: Mon, 12 Oct 2020 15:48:16 +0800
Subject: [PATCH 1/3] check code

---
 .../org/apache/spark/ml/classification/LogisticRegression.scala | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala b/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala
index 4d763cbd29d3c..b535ed59497ad 100644
--- a/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala
+++ b/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala
@@ -1104,6 +1104,7 @@ class LogisticRegressionModel private[spark] (
   private var _rawThreshold = Double.NaN
 
   updateBinaryThreshold()
+  log.warn(s"_threshold=${_threshold}, _rawThreshold=${_rawThreshold}")
 
   private def updateBinaryThreshold(): Unit = {
     if (!isMultinomial) {
@@ -1205,6 +1206,7 @@ class LogisticRegressionModel private[spark] (
     super.predict(features)
   } else {
     // Note: We should use _threshold instead of $(threshold) since getThreshold is overridden.
+    log.warn(s"_threshold=${_threshold}, _rawThreshold=${_rawThreshold}")
     if (score(features) > _threshold) 1 else 0
   }
 

From 49690ebc06855231394000704a59e9f53cc69c5c Mon Sep 17 00:00:00 2001
From: zhengruifeng <ruifengz@foxmail.com>
Date: Mon, 12 Oct 2020 16:04:33 +0800
Subject: [PATCH 2/3] use lazy array

use lazy array
---
 .../classification/LogisticRegression.scala   | 28 ++++++++++---------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala b/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala
index b535ed59497ad..a43ad466a7c80 100644
--- a/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala
+++ b/mllib/src/main/scala/org/apache/spark/ml/classification/LogisticRegression.scala
@@ -1100,21 +1100,24 @@ class LogisticRegressionModel private[spark] (
 
   private lazy val _intercept = interceptVector(0)
   private lazy val _interceptVector = interceptVector.toDense
-  private var _threshold = Double.NaN
-  private var _rawThreshold = Double.NaN
-
-  updateBinaryThreshold()
-  log.warn(s"_threshold=${_threshold}, _rawThreshold=${_rawThreshold}")
+  private lazy val _binaryThresholdArray = {
+    val array = Array(Double.NaN, Double.NaN)
+    updateBinaryThresholds(array)
+    array
+  }
+  private def _threshold: Double = _binaryThresholdArray(0)
+  private def _rawThreshold: Double = _binaryThresholdArray(1)
 
-  private def updateBinaryThreshold(): Unit = {
+  private def updateBinaryThresholds(array: Array[Double]): Unit = {
     if (!isMultinomial) {
-      _threshold = getThreshold
+      val _threshold = getThreshold
+      array(0) = _threshold
       if (_threshold == 0.0) {
-        _rawThreshold = Double.NegativeInfinity
+        array(1) = Double.NegativeInfinity
       } else if (_threshold == 1.0) {
-        _rawThreshold = Double.PositiveInfinity
+        array(1) = Double.PositiveInfinity
       } else {
-        _rawThreshold = math.log(_threshold / (1.0 - _threshold))
+        array(1) = math.log(_threshold / (1.0 - _threshold))
       }
     }
   }
@@ -1122,7 +1125,7 @@ class LogisticRegressionModel private[spark] (
   @Since("1.5.0")
   override def setThreshold(value: Double): this.type = {
     super.setThreshold(value)
-    updateBinaryThreshold()
+    updateBinaryThresholds(_binaryThresholdArray)
     this
   }
 
@@ -1132,7 +1135,7 @@ class LogisticRegressionModel private[spark] (
   @Since("1.5.0")
   override def setThresholds(value: Array[Double]): this.type = {
     super.setThresholds(value)
-    updateBinaryThreshold()
+    updateBinaryThresholds(_binaryThresholdArray)
     this
   }
 
@@ -1206,7 +1209,6 @@ class LogisticRegressionModel private[spark] (
     super.predict(features)
   } else {
     // Note: We should use _threshold instead of $(threshold) since getThreshold is overridden.
-    log.warn(s"_threshold=${_threshold}, _rawThreshold=${_rawThreshold}")
     if (score(features) > _threshold) 1 else 0
   }
 

From 7a1749c2e4c40ded1546c7ce3f0a6b190c340c84 Mon Sep 17 00:00:00 2001
From: zhengruifeng <ruifengz@foxmail.com>
Date: Tue, 13 Oct 2020 09:56:06 +0800
Subject: [PATCH 3/3] update testsuite

---
 .../spark/ml/classification/LogisticRegressionSuite.scala      | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mllib/src/test/scala/org/apache/spark/ml/classification/LogisticRegressionSuite.scala b/mllib/src/test/scala/org/apache/spark/ml/classification/LogisticRegressionSuite.scala
index 56eadff6df078..51a6ae3c7e49b 100644
--- a/mllib/src/test/scala/org/apache/spark/ml/classification/LogisticRegressionSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/ml/classification/LogisticRegressionSuite.scala
@@ -400,10 +400,9 @@ class LogisticRegressionSuite extends MLTest with DefaultReadWriteTest {
   }
 
   test("thresholds prediction") {
-    val blr = new LogisticRegression().setFamily("binomial")
+    val blr = new LogisticRegression().setFamily("binomial").setThreshold(1.0)
     val binaryModel = blr.fit(smallBinaryDataset)
 
-    binaryModel.setThreshold(1.0)
     testTransformer[(Double, Vector)](smallBinaryDataset.toDF(), binaryModel, "prediction") {
       row => assert(row.getDouble(0) === 0.0)
     }