Add spellcheck and word suggestion to the prediction service

third_party/android_prediction/suggest/core/layout/normal_distribution_2d.h

Index: third_party/android_prediction/suggest/core/layout/normal_distribution_2d.h
diff --git a/third_party/android_prediction/suggest/core/layout/normal_distribution_2d.h b/third_party/android_prediction/suggest/core/layout/normal_distribution_2d.h
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+/*
+ * Copyright (C) 2014 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.
+ */
+
+#ifndef LATINIME_NORMAL_DISTRIBUTION_2D_H
+#define LATINIME_NORMAL_DISTRIBUTION_2D_H
+
+#include <cmath>
+
+#include "third_party/android_prediction/defines.h"
+#include "third_party/android_prediction/suggest/core/layout/geometry_utils.h"
+#include "third_party/android_prediction/suggest/core/layout/normal_distribution.h"
+
+namespace latinime {
+
+// Normal distribution on a 2D plane. The covariance is always zero, but the distribution can be
+// rotated.
+class NormalDistribution2D {
+ public:
+    NormalDistribution2D(const float uX, const float sigmaX, const float uY, const float sigmaY,
+            const float theta)
+            : mXDistribution(0.0f, sigmaX), mYDistribution(0.0f, sigmaY), mUX(uX), mUY(uY),
+              mSinTheta(sinf(theta)), mCosTheta(cosf(theta)) {}
+
+    float getProbabilityDensity(const float x, const float y) const {
+        // Shift
+        const float shiftedX = x - mUX;
+        const float shiftedY = y - mUY;
+        // Rotate
+        const float rotatedShiftedX = mCosTheta * shiftedX + mSinTheta * shiftedY;
+        const float rotatedShiftedY = -mSinTheta * shiftedX + mCosTheta * shiftedY;
+        return mXDistribution.getProbabilityDensity(rotatedShiftedX)
+                * mYDistribution.getProbabilityDensity(rotatedShiftedY);
+    }
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(NormalDistribution2D);
+
+    const NormalDistribution mXDistribution;
+    const NormalDistribution mYDistribution;
+    const float mUX;
+    const float mUY;
+    const float mSinTheta;
+    const float mCosTheta;
+};
+} // namespace latinime
+#endif // LATINIME_NORMAL_DISTRIBUTION_2D_H