Add NativeUtils.powf()

Change-Id: I0339f39d49bc6390d098017f32d92c776974e03e

2 files changed, 34 insertions, 2 deletions

diff --git a/java/src/com/android/inputmethod/latin/NativeUtils.java b/java/src/com/android/inputmethod/latin/NativeUtils.java
new file mode 100644
index 000000000..9cc2bc02e
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/NativeUtils.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed 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 com.android.inputmethod.latin;
+
+public class NativeUtils {
+    static {
+        JniUtils.loadNativeLibrary();
+    }
+
+    private NativeUtils() {
+        // This utility class is not publicly instantiable.
+    }
+
+    /**
+     * This method just calls up libm's powf() directly.
+     */
+    public static native float powf(float x, float y);
+}
diff --git a/java/src/com/android/inputmethod/latin/UserHistoryForgettingCurveUtils.java b/java/src/com/android/inputmethod/latin/UserHistoryForgettingCurveUtils.java
index 6e71885cc..1de95d7b8 100644
--- a/java/src/com/android/inputmethod/latin/UserHistoryForgettingCurveUtils.java
+++ b/java/src/com/android/inputmethod/latin/UserHistoryForgettingCurveUtils.java
@@ -211,8 +211,8 @@ public class UserHistoryForgettingCurveUtils {
                 }
                 for (int j = 0; j < ELAPSED_TIME_MAX; ++j) {
                     final float elapsedHours = j * ELAPSED_TIME_INTERVAL_HOURS;
-                    final double freq =
-                            initialFreq * Math.pow(initialFreq, elapsedHours / HALF_LIFE_HOURS);
+                    final float freq = initialFreq
+                            * NativeUtils.powf(initialFreq, elapsedHours / HALF_LIFE_HOURS);
                     final int intFreq = Math.min(FC_FREQ_MAX, Math.max(0, (int)freq));
                     SCORE_TABLE[i][j] = intFreq;
                 }