Add smoothing utils / matrix libs
Bug: 8556775 Change-Id: I7e0516b344937b84b7d57cc4e5009b7f88e7dc98main
Satoshi Kataoka
parent
2115f63cba
commit
c92e87faf3
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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.inputmethod.keyboard.internal;
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import com.android.inputmethod.annotations.UsedForTesting;
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import android.util.Log;
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import java.util.Arrays;
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/**
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* Utilities for matrix operations. Don't instantiate objects inside this class to prevent
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* unexpected performance regressions.
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*/
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@UsedForTesting
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public class MatrixUtils {
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private static final String TAG = MatrixUtils.class.getSimpleName();
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public static class MatrixOperationFailedException extends Exception {
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private static final String TAG = MatrixOperationFailedException.class.getSimpleName();
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private static final long serialVersionUID = 4384485606788583829L;
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public MatrixOperationFailedException(String msg) {
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super(msg);
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Log.d(TAG, msg);
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}
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}
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/**
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* A utility function to inverse matrix.
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* Find a pivot and swap the row of squareMatrix0 and squareMatrix1
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*/
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private static void findPivotAndSwapRow(final int row, final float[][] squareMatrix0,
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final float[][] squareMatrix1, final int size) {
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int ip = row;
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float pivot = Math.abs(squareMatrix0[row][row]);
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for (int i = row + 1; i < size; ++i) {
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if (pivot < Math.abs(squareMatrix0[i][row])) {
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ip = i;
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pivot = Math.abs(squareMatrix0[i][row]);
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}
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}
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if (ip != row) {
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for (int j = 0; j < size; ++j) {
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final float temp0 = squareMatrix0[ip][j];
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squareMatrix0[ip][j] = squareMatrix0[row][j];
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squareMatrix0[row][j] = temp0;
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final float temp1 = squareMatrix1[ip][j];
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squareMatrix1[ip][j] = squareMatrix1[row][j];
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squareMatrix1[row][j] = temp1;
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}
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}
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}
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/**
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* A utility function to inverse matrix. This function calculates answer for each row by
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* sweeping method of Gauss Jordan elimination
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*/
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private static void sweep(final int row, final float[][] squareMatrix0,
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final float[][] squareMatrix1, final int size) throws MatrixOperationFailedException {
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final float pivot = squareMatrix0[row][row];
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if (pivot == 0) {
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throw new MatrixOperationFailedException("Inverse failed. Invalid pivot");
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}
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for (int j = 0; j < size; ++j) {
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squareMatrix0[row][j] /= pivot;
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squareMatrix1[row][j] /= pivot;
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}
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for (int i = 0; i < size; i++) {
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final float sweepTargetValue = squareMatrix0[i][row];
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if (i != row) {
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for (int j = row; j < size; ++j) {
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squareMatrix0[i][j] -= sweepTargetValue * squareMatrix0[row][j];
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}
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for (int j = 0; j < size; ++j) {
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squareMatrix1[i][j] -= sweepTargetValue * squareMatrix1[row][j];
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}
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}
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}
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}
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/**
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* A function to inverse matrix.
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* The inverse matrix of squareMatrix will be output to inverseMatrix. Please notice that
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* the value of squareMatrix is modified in this function and can't be resuable.
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*/
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@UsedForTesting
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public static void inverse(final float[][] squareMatrix,
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final float[][] inverseMatrix) throws MatrixOperationFailedException {
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final int size = squareMatrix.length;
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if (squareMatrix[0].length != size || inverseMatrix.length != size
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|| inverseMatrix[0].length != size) {
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throw new MatrixOperationFailedException(
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"--- invalid length. column should be 2 times larger than row.");
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}
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for (int i = 0; i < size; ++i) {
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Arrays.fill(inverseMatrix[i], 0.0f);
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inverseMatrix[i][i] = 1.0f;
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}
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for (int i = 0; i < size; ++i) {
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findPivotAndSwapRow(i, squareMatrix, inverseMatrix, size);
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sweep(i, squareMatrix, inverseMatrix, size);
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}
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}
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/**
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* A matrix operation to multiply m0 and m1.
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*/
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@UsedForTesting
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public static void multiply(final float[][] m0, final float[][] m1,
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final float[][] retval) throws MatrixOperationFailedException {
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if (m0[0].length != m1.length) {
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throw new MatrixOperationFailedException(
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"--- invalid length for multiply " + m0[0].length + ", " + m1.length);
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}
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final int m0h = m0.length;
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final int m0w = m0[0].length;
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final int m1w = m1[0].length;
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if (retval.length != m0h || retval[0].length != m1w) {
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throw new MatrixOperationFailedException(
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"--- invalid length of retval " + retval.length + ", " + retval[0].length);
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}
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for (int i = 0; i < m0h; i++) {
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Arrays.fill(retval[i], 0);
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for (int j = 0; j < m1w; j++) {
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for (int k = 0; k < m0w; k++) {
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retval[i][j] += m0[i][k] * m1[k][j];
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}
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}
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}
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}
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/**
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* A utility function to dump the specified matrix in a readable way
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*/
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@UsedForTesting
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public static void dump(final String title, final float[][] a) {
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final int column = a[0].length;
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final int row = a.length;
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Log.d(TAG, "Dump matrix: " + title);
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Log.d(TAG, "/*---------------------");
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final StringBuilder sb = new StringBuilder();
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for (int i = 0; i < row; ++i) {
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sb.setLength(0);
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for (int j = 0; j < column; ++j) {
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sb.append(String.format("%4f", a[i][j])).append(' ');
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}
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Log.d(TAG, sb.toString());
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}
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Log.d(TAG, "---------------------*/");
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}
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}
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@ -0,0 +1,102 @@
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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.inputmethod.keyboard.internal;
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import com.android.inputmethod.annotations.UsedForTesting;
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import com.android.inputmethod.keyboard.internal.MatrixUtils.MatrixOperationFailedException;
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import android.util.Log;
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import java.util.Arrays;
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/**
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* Utilities to smooth coordinates. Currently, we calculate 3d least squares formula by using
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* Lagrangian smoothing
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*/
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@UsedForTesting
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public class SmoothingUtils {
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private static final String TAG = SmoothingUtils.class.getSimpleName();
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private static final boolean DEBUG = false;
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private SmoothingUtils() {
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// not allowed to instantiate publicly
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}
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/**
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* Find a most likely 3d least squares formula for specified coordinates.
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* "retval" should be a 1x4 size matrix.
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*/
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@UsedForTesting
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public static void get3DParameters(final float[] xs, final float[] ys,
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final float[][] retval) throws MatrixOperationFailedException {
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final int COEFF_COUNT = 4; // Coefficient count for 3d smoothing
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if (retval.length != COEFF_COUNT || retval[0].length != 1) {
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Log.d(TAG, "--- invalid length of 3d retval " + retval.length + ", "
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+ retval[0].length);
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return;
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}
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final int N = xs.length;
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// TODO: Never isntantiate the matrix
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final float[][] m0 = new float[COEFF_COUNT][COEFF_COUNT];
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final float[][] m0Inv = new float[COEFF_COUNT][COEFF_COUNT];
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final float[][] m1 = new float[COEFF_COUNT][N];
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final float[][] m2 = new float[N][1];
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// m0
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for (int i = 0; i < COEFF_COUNT; ++i) {
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Arrays.fill(m0[i], 0);
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for (int j = 0; j < COEFF_COUNT; ++j) {
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final int pow = i + j;
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for (int k = 0; k < N; ++k) {
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m0[i][j] += (float) Math.pow((double) xs[k], pow);
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}
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}
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}
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// m0Inv
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MatrixUtils.inverse(m0, m0Inv);
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if (DEBUG) {
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MatrixUtils.dump("m0-1", m0Inv);
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}
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// m1
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for (int i = 0; i < COEFF_COUNT; ++i) {
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for (int j = 0; j < N; ++j) {
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m1[i][j] = (i == 0) ? 1.0f : m1[i - 1][j] * xs[j];
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}
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}
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// m2
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for (int i = 0; i < N; ++i) {
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m2[i][0] = ys[i];
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}
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final float[][] m0Invxm1 = new float[COEFF_COUNT][N];
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if (DEBUG) {
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MatrixUtils.dump("a0", m0Inv);
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MatrixUtils.dump("a1", m1);
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}
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MatrixUtils.multiply(m0Inv, m1, m0Invxm1);
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if (DEBUG) {
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MatrixUtils.dump("a2", m0Invxm1);
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MatrixUtils.dump("a3", m2);
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}
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MatrixUtils.multiply(m0Invxm1, m2, retval);
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if (DEBUG) {
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MatrixUtils.dump("result", retval);
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}
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}
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}
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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.inputmethod.keyboard.internal;
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import com.android.inputmethod.keyboard.internal.MatrixUtils.MatrixOperationFailedException;
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import android.test.AndroidTestCase;
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import android.test.suitebuilder.annotation.SmallTest;
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@SmallTest
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public class MatrixUtilsTests extends AndroidTestCase {
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// "run tests" -c com.android.inputmethod.keyboard.internal.MatrixUtilsTests
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private static final boolean DEBUG = false;
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private static final float EPSILON = 0.00001f;
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private static void assertEqualsFloat(float f0, float f1) {
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assertEqualsFloat(f0, f1, EPSILON);
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}
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/* package */ static void assertEqualsFloat(float f0, float f1, float error) {
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assertTrue(Math.abs(f0 - f1) < error);
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}
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public void testMulti() {
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final float[][] matrixA = {{1, 2}, {3, 4}};
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final float[][] matrixB = {{5, 6}, {7, 8}};
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final float[][] retval = new float[2][2];
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try {
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MatrixUtils.multiply(matrixA, matrixB, retval);
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} catch (MatrixOperationFailedException e) {
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assertTrue(false);
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}
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if (DEBUG) {
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MatrixUtils.dump("multi", retval);
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}
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assertEqualsFloat(retval[0][0], 19);
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assertEqualsFloat(retval[0][1], 22);
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assertEqualsFloat(retval[1][0], 43);
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assertEqualsFloat(retval[1][1], 50);
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}
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public void testInverse() {
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final int N = 4;
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final float[][] matrix =
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{{1, 2, 3, 4}, {4, 0, 5, 6}, {6, 4, 2, 0}, {6, 4, 2, 1}};
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final float[][] inverse = new float[N][N];
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final float[][] tempMatrix = new float[N][N];
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for (int i = 0; i < N; ++i) {
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for (int j = 0; j < N; ++j) {
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tempMatrix[i][j] = matrix[i][j];
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}
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}
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final float[][] retval = new float[N][N];
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try {
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MatrixUtils.inverse(tempMatrix, inverse);
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} catch (MatrixOperationFailedException e) {
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assertTrue(false);
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}
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try {
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MatrixUtils.multiply(matrix, inverse, retval);
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} catch (MatrixOperationFailedException e) {
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assertTrue(false);
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}
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for (int i = 0; i < N; ++i) {
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for (int j = 0; j < N; ++j) {
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assertEqualsFloat(((i == j) ? 1.0f : 0.0f), retval[i][j]);
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}
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}
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}
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}
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@ -0,0 +1,45 @@
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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.inputmethod.keyboard.internal;
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import com.android.inputmethod.keyboard.internal.MatrixUtils.MatrixOperationFailedException;
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import android.test.AndroidTestCase;
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import android.test.suitebuilder.annotation.SmallTest;
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@SmallTest
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public class SmoothingUtilsTests extends AndroidTestCase {
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// "run tests" -c com.android.inputmethod.keyboard.internal.SmoothingUtilsTests
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private static final boolean DEBUG = false;
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public void testGet3DParamaters() {
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final float[] xs = new float[] {0, 1, 2, 3, 4};
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final float[] ys = new float[] {1, 4, 15, 40, 85}; // y = x^3 + x^2 + x + 1
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final float[][] retval = new float[4][1];
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try {
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SmoothingUtils.get3DParameters(xs, ys, retval);
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if (DEBUG) {
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MatrixUtils.dump("3d", retval);
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}
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for (int i = 0; i < 4; ++i) {
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MatrixUtilsTests.assertEqualsFloat(retval[i][0], 1.0f, 0.001f);
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}
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} catch (MatrixOperationFailedException e) {
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assertTrue(false);
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}
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}
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}
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