Merge "Add smoothing utils / matrix libs" (a2d8d30f) · Commits · e / os / android_packages_inputmethods_LatinIME

java/src/com/android/inputmethod/keyboard/internal/MatrixUtils.java

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		/*
		* Copyright (C) 2013 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.keyboard.internal;

		import com.android.inputmethod.annotations.UsedForTesting;

		import android.util.Log;

		import java.util.Arrays;

		/**
		* Utilities for matrix operations. Don't instantiate objects inside this class to prevent
		* unexpected performance regressions.
		*/
		@UsedForTesting
		public class MatrixUtils {
		private static final String TAG = MatrixUtils.class.getSimpleName();
		public static class MatrixOperationFailedException extends Exception {
		private static final String TAG = MatrixOperationFailedException.class.getSimpleName();
		private static final long serialVersionUID = 4384485606788583829L;

		public MatrixOperationFailedException(String msg) {
		super(msg);
		Log.d(TAG, msg);
		}
		}

		/**
		* A utility function to inverse matrix.
		* Find a pivot and swap the row of squareMatrix0 and squareMatrix1
		*/
		private static void findPivotAndSwapRow(final int row, final float[][] squareMatrix0,
		final float[][] squareMatrix1, final int size) {
		int ip = row;
		float pivot = Math.abs(squareMatrix0[row][row]);
		for (int i = row + 1; i < size; ++i) {
		if (pivot < Math.abs(squareMatrix0[i][row])) {
		ip = i;
		pivot = Math.abs(squareMatrix0[i][row]);
		}
		}
		if (ip != row) {
		for (int j = 0; j < size; ++j) {
		final float temp0 = squareMatrix0[ip][j];
		squareMatrix0[ip][j] = squareMatrix0[row][j];
		squareMatrix0[row][j] = temp0;
		final float temp1 = squareMatrix1[ip][j];
		squareMatrix1[ip][j] = squareMatrix1[row][j];
		squareMatrix1[row][j] = temp1;
		}
		}
		}

		/**
		* A utility function to inverse matrix. This function calculates answer for each row by
		* sweeping method of Gauss Jordan elimination
		*/
		private static void sweep(final int row, final float[][] squareMatrix0,
		final float[][] squareMatrix1, final int size) throws MatrixOperationFailedException {
		final float pivot = squareMatrix0[row][row];
		if (pivot == 0) {
		throw new MatrixOperationFailedException("Inverse failed. Invalid pivot");
		}
		for (int j = 0; j < size; ++j) {
		squareMatrix0[row][j] /= pivot;
		squareMatrix1[row][j] /= pivot;
		}
		for (int i = 0; i < size; i++) {
		final float sweepTargetValue = squareMatrix0[i][row];
		if (i != row) {
		for (int j = row; j < size; ++j) {
		squareMatrix0[i][j] -= sweepTargetValue * squareMatrix0[row][j];
		}
		for (int j = 0; j < size; ++j) {
		squareMatrix1[i][j] -= sweepTargetValue * squareMatrix1[row][j];
		}
		}
		}
		}

		/**
		* A function to inverse matrix.
		* The inverse matrix of squareMatrix will be output to inverseMatrix. Please notice that
		* the value of squareMatrix is modified in this function and can't be resuable.
		*/
		@UsedForTesting
		public static void inverse(final float[][] squareMatrix,
		final float[][] inverseMatrix) throws MatrixOperationFailedException {
		final int size = squareMatrix.length;
		if (squareMatrix[0].length != size \|\| inverseMatrix.length != size
		\|\| inverseMatrix[0].length != size) {
		throw new MatrixOperationFailedException(
		"--- invalid length. column should be 2 times larger than row.");
		}
		for (int i = 0; i < size; ++i) {
		Arrays.fill(inverseMatrix[i], 0.0f);
		inverseMatrix[i][i] = 1.0f;
		}
		for (int i = 0; i < size; ++i) {
		findPivotAndSwapRow(i, squareMatrix, inverseMatrix, size);
		sweep(i, squareMatrix, inverseMatrix, size);
		}
		}

		/**
		* A matrix operation to multiply m0 and m1.
		*/
		@UsedForTesting
		public static void multiply(final float[][] m0, final float[][] m1,
		final float[][] retval) throws MatrixOperationFailedException {
		if (m0[0].length != m1.length) {
		throw new MatrixOperationFailedException(
		"--- invalid length for multiply " + m0[0].length + ", " + m1.length);
		}
		final int m0h = m0.length;
		final int m0w = m0[0].length;
		final int m1w = m1[0].length;
		if (retval.length != m0h \|\| retval[0].length != m1w) {
		throw new MatrixOperationFailedException(
		"--- invalid length of retval " + retval.length + ", " + retval[0].length);
		}

		for (int i = 0; i < m0h; i++) {
		Arrays.fill(retval[i], 0);
		for (int j = 0; j < m1w; j++) {
		for (int k = 0; k < m0w; k++) {
		retval[i][j] += m0[i][k] * m1[k][j];
		}
		}
		}
		}

		/**
		* A utility function to dump the specified matrix in a readable way
		*/
		@UsedForTesting
		public static void dump(final String title, final float[][] a) {
		final int column = a[0].length;
		final int row = a.length;
		Log.d(TAG, "Dump matrix: " + title);
		Log.d(TAG, "/*---------------------");
		final StringBuilder sb = new StringBuilder();
		for (int i = 0; i < row; ++i) {
		sb.setLength(0);
		for (int j = 0; j < column; ++j) {
		sb.append(String.format("%4f", a[i][j])).append(' ');
		}
		Log.d(TAG, sb.toString());
		}
		Log.d(TAG, "---------------------*/");
		}
		}

java/src/com/android/inputmethod/keyboard/internal/SmoothingUtils.java

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		/*
		* Copyright (C) 2013 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.keyboard.internal;

		import com.android.inputmethod.annotations.UsedForTesting;
		import com.android.inputmethod.keyboard.internal.MatrixUtils.MatrixOperationFailedException;

		import android.util.Log;

		import java.util.Arrays;

		/**
		* Utilities to smooth coordinates. Currently, we calculate 3d least squares formula by using
		* Lagrangian smoothing
		*/
		@UsedForTesting
		public class SmoothingUtils {
		private static final String TAG = SmoothingUtils.class.getSimpleName();
		private static final boolean DEBUG = false;

		private SmoothingUtils() {
		// not allowed to instantiate publicly
		}

		/**
		* Find a most likely 3d least squares formula for specified coordinates.
		* "retval" should be a 1x4 size matrix.
		*/
		@UsedForTesting
		public static void get3DParameters(final float[] xs, final float[] ys,
		final float[][] retval) throws MatrixOperationFailedException {
		final int COEFF_COUNT = 4; // Coefficient count for 3d smoothing
		if (retval.length != COEFF_COUNT \|\| retval[0].length != 1) {
		Log.d(TAG, "--- invalid length of 3d retval " + retval.length + ", "
		+ retval[0].length);
		return;
		}
		final int N = xs.length;
		// TODO: Never isntantiate the matrix
		final float[][] m0 = new float[COEFF_COUNT][COEFF_COUNT];
		final float[][] m0Inv = new float[COEFF_COUNT][COEFF_COUNT];
		final float[][] m1 = new float[COEFF_COUNT][N];
		final float[][] m2 = new float[N][1];

		// m0
		for (int i = 0; i < COEFF_COUNT; ++i) {
		Arrays.fill(m0[i], 0);
		for (int j = 0; j < COEFF_COUNT; ++j) {
		final int pow = i + j;
		for (int k = 0; k < N; ++k) {
		m0[i][j] += (float) Math.pow((double) xs[k], pow);
		}
		}
		}
		// m0Inv
		MatrixUtils.inverse(m0, m0Inv);
		if (DEBUG) {
		MatrixUtils.dump("m0-1", m0Inv);
		}

		// m1
		for (int i = 0; i < COEFF_COUNT; ++i) {
		for (int j = 0; j < N; ++j) {
		m1[i][j] = (i == 0) ? 1.0f : m1[i - 1][j] * xs[j];
		}
		}

		// m2
		for (int i = 0; i < N; ++i) {
		m2[i][0] = ys[i];
		}

		final float[][] m0Invxm1 = new float[COEFF_COUNT][N];
		if (DEBUG) {
		MatrixUtils.dump("a0", m0Inv);
		MatrixUtils.dump("a1", m1);
		}
		MatrixUtils.multiply(m0Inv, m1, m0Invxm1);
		if (DEBUG) {
		MatrixUtils.dump("a2", m0Invxm1);
		MatrixUtils.dump("a3", m2);
		}
		MatrixUtils.multiply(m0Invxm1, m2, retval);
		if (DEBUG) {
		MatrixUtils.dump("result", retval);
		}
		}
		}

tests/src/com/android/inputmethod/keyboard/internal/MatrixUtilsTests.java

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		/*
		* Copyright (C) 2013 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.keyboard.internal;

		import com.android.inputmethod.keyboard.internal.MatrixUtils.MatrixOperationFailedException;

		import android.test.AndroidTestCase;
		import android.test.suitebuilder.annotation.SmallTest;

		@SmallTest
		public class MatrixUtilsTests extends AndroidTestCase {
		// "run tests" -c com.android.inputmethod.keyboard.internal.MatrixUtilsTests
		private static final boolean DEBUG = false;
		private static final float EPSILON = 0.00001f;

		private static void assertEqualsFloat(float f0, float f1) {
		assertEqualsFloat(f0, f1, EPSILON);
		}

		/* package */ static void assertEqualsFloat(float f0, float f1, float error) {
		assertTrue(Math.abs(f0 - f1) < error);
		}

		public void testMulti() {
		final float[][] matrixA = {{1, 2}, {3, 4}};
		final float[][] matrixB = {{5, 6}, {7, 8}};
		final float[][] retval = new float[2][2];
		try {
		MatrixUtils.multiply(matrixA, matrixB, retval);
		} catch (MatrixOperationFailedException e) {
		assertTrue(false);
		}
		if (DEBUG) {
		MatrixUtils.dump("multi", retval);
		}
		assertEqualsFloat(retval[0][0], 19);
		assertEqualsFloat(retval[0][1], 22);
		assertEqualsFloat(retval[1][0], 43);
		assertEqualsFloat(retval[1][1], 50);
		}

		public void testInverse() {
		final int N = 4;
		final float[][] matrix =
		{{1, 2, 3, 4}, {4, 0, 5, 6}, {6, 4, 2, 0}, {6, 4, 2, 1}};
		final float[][] inverse = new float[N][N];
		final float[][] tempMatrix = new float[N][N];
		for (int i = 0; i < N; ++i) {
		for (int j = 0; j < N; ++j) {
		tempMatrix[i][j] = matrix[i][j];
		}
		}
		final float[][] retval = new float[N][N];
		try {
		MatrixUtils.inverse(tempMatrix, inverse);
		} catch (MatrixOperationFailedException e) {
		assertTrue(false);
		}
		try {
		MatrixUtils.multiply(matrix, inverse, retval);
		} catch (MatrixOperationFailedException e) {
		assertTrue(false);
		}
		for (int i = 0; i < N; ++i) {
		for (int j = 0; j < N; ++j) {
		assertEqualsFloat(((i == j) ? 1.0f : 0.0f), retval[i][j]);
		}
		}
		}
		}

tests/src/com/android/inputmethod/keyboard/internal/SmoothingUtilsTests.java

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		/*
		* Copyright (C) 2013 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.keyboard.internal;

		import com.android.inputmethod.keyboard.internal.MatrixUtils.MatrixOperationFailedException;

		import android.test.AndroidTestCase;
		import android.test.suitebuilder.annotation.SmallTest;

		@SmallTest
		public class SmoothingUtilsTests extends AndroidTestCase {
		// "run tests" -c com.android.inputmethod.keyboard.internal.SmoothingUtilsTests
		private static final boolean DEBUG = false;

		public void testGet3DParamaters() {
		final float[] xs = new float[] {0, 1, 2, 3, 4};
		final float[] ys = new float[] {1, 4, 15, 40, 85}; // y = x^3 + x^2 + x + 1
		final float[][] retval = new float[4][1];
		try {
		SmoothingUtils.get3DParameters(xs, ys, retval);
		if (DEBUG) {
		MatrixUtils.dump("3d", retval);
		}
		for (int i = 0; i < 4; ++i) {
		MatrixUtilsTests.assertEqualsFloat(retval[i][0], 1.0f, 0.001f);
		}
		} catch (MatrixOperationFailedException e) {
		assertTrue(false);
		}
		}
		}