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With inspiration from other libraries
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.commons.math3.linear;
import java.text.FieldPosition;
import java.text.NumberFormat;
import java.text.ParsePosition;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import org.apache.commons.math3.exception.MathParseException;
import org.apache.commons.math3.util.CompositeFormat;
/**
* Formats a {@code nxm} matrix in components list format
* "{{a00,a01, ...,
* a0m-1},{a10,
* a11, ..., a1m-1},{...},{
* an-10, an-11, ...,
* an-1m-1}}".
* The prefix and suffix "{" and "}", the row prefix and suffix "{" and "}",
* the row separator "," and the column separator "," can be replaced by any
* user-defined strings. The number format for components can be configured.
*
* White space is ignored at parse time, even if it is in the prefix, suffix
* or separator specifications. So even if the default separator does include a space
* character that is used at format time, both input string "{{1,1,1}}" and
* " { { 1 , 1 , 1 } } " will be parsed without error and the same matrix will be
* returned. In the second case, however, the parse position after parsing will be
* just after the closing curly brace, i.e. just before the trailing space.
*
* Note: the grouping functionality of the used {@link NumberFormat} is
* disabled to prevent problems when parsing (e.g. 1,345.34 would be a valid number
* but conflicts with the default column separator).
*
* @since 3.1
*/
public class RealMatrixFormat {
/** The default prefix: "{". */
private static final String DEFAULT_PREFIX = "{";
/** The default suffix: "}". */
private static final String DEFAULT_SUFFIX = "}";
/** The default row prefix: "{". */
private static final String DEFAULT_ROW_PREFIX = "{";
/** The default row suffix: "}". */
private static final String DEFAULT_ROW_SUFFIX = "}";
/** The default row separator: ",". */
private static final String DEFAULT_ROW_SEPARATOR = ",";
/** The default column separator: ",". */
private static final String DEFAULT_COLUMN_SEPARATOR = ",";
/** Prefix. */
private final String prefix;
/** Suffix. */
private final String suffix;
/** Row prefix. */
private final String rowPrefix;
/** Row suffix. */
private final String rowSuffix;
/** Row separator. */
private final String rowSeparator;
/** Column separator. */
private final String columnSeparator;
/** The format used for components. */
private final NumberFormat format;
/**
* Create an instance with default settings.
* The instance uses the default prefix, suffix and row/column separator:
* "[", "]", ";" and ", " and the default number format for components.
*/
public RealMatrixFormat() {
this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ROW_PREFIX, DEFAULT_ROW_SUFFIX,
DEFAULT_ROW_SEPARATOR, DEFAULT_COLUMN_SEPARATOR, CompositeFormat.getDefaultNumberFormat());
}
/**
* Create an instance with a custom number format for components.
* @param format the custom format for components.
*/
public RealMatrixFormat(final NumberFormat format) {
this(DEFAULT_PREFIX, DEFAULT_SUFFIX, DEFAULT_ROW_PREFIX, DEFAULT_ROW_SUFFIX,
DEFAULT_ROW_SEPARATOR, DEFAULT_COLUMN_SEPARATOR, format);
}
/**
* Create an instance with custom prefix, suffix and separator.
* @param prefix prefix to use instead of the default "{"
* @param suffix suffix to use instead of the default "}"
* @param rowPrefix row prefix to use instead of the default "{"
* @param rowSuffix row suffix to use instead of the default "}"
* @param rowSeparator tow separator to use instead of the default ";"
* @param columnSeparator column separator to use instead of the default ", "
*/
public RealMatrixFormat(final String prefix, final String suffix,
final String rowPrefix, final String rowSuffix,
final String rowSeparator, final String columnSeparator) {
this(prefix, suffix, rowPrefix, rowSuffix, rowSeparator, columnSeparator,
CompositeFormat.getDefaultNumberFormat());
}
/**
* Create an instance with custom prefix, suffix, separator and format
* for components.
* @param prefix prefix to use instead of the default "{"
* @param suffix suffix to use instead of the default "}"
* @param rowPrefix row prefix to use instead of the default "{"
* @param rowSuffix row suffix to use instead of the default "}"
* @param rowSeparator tow separator to use instead of the default ";"
* @param columnSeparator column separator to use instead of the default ", "
* @param format the custom format for components.
*/
public RealMatrixFormat(final String prefix, final String suffix,
final String rowPrefix, final String rowSuffix,
final String rowSeparator, final String columnSeparator,
final NumberFormat format) {
this.prefix = prefix;
this.suffix = suffix;
this.rowPrefix = rowPrefix;
this.rowSuffix = rowSuffix;
this.rowSeparator = rowSeparator;
this.columnSeparator = columnSeparator;
this.format = format;
// disable grouping to prevent parsing problems
this.format.setGroupingUsed(false);
}
/**
* Get the set of locales for which real vectors formats are available.
* This is the same set as the {@link NumberFormat} set.
* @return available real vector format locales.
*/
public static Locale[] getAvailableLocales() {
return NumberFormat.getAvailableLocales();
}
/**
* Get the format prefix.
* @return format prefix.
*/
public String getPrefix() {
return prefix;
}
/**
* Get the format suffix.
* @return format suffix.
*/
public String getSuffix() {
return suffix;
}
/**
* Get the format prefix.
* @return format prefix.
*/
public String getRowPrefix() {
return rowPrefix;
}
/**
* Get the format suffix.
* @return format suffix.
*/
public String getRowSuffix() {
return rowSuffix;
}
/**
* Get the format separator between rows of the matrix.
* @return format separator for rows.
*/
public String getRowSeparator() {
return rowSeparator;
}
/**
* Get the format separator between components.
* @return format separator between components.
*/
public String getColumnSeparator() {
return columnSeparator;
}
/**
* Get the components format.
* @return components format.
*/
public NumberFormat getFormat() {
return format;
}
/**
* Returns the default real vector format for the current locale.
* @return the default real vector format.
*/
public static RealMatrixFormat getInstance() {
return getInstance(Locale.getDefault());
}
/**
* Returns the default real vector format for the given locale.
* @param locale the specific locale used by the format.
* @return the real vector format specific to the given locale.
*/
public static RealMatrixFormat getInstance(final Locale locale) {
return new RealMatrixFormat(CompositeFormat.getDefaultNumberFormat(locale));
}
/**
* This method calls {@link #format(RealMatrix,StringBuffer,FieldPosition)}.
*
* @param m RealMatrix object to format.
* @return a formatted matrix.
*/
public String format(RealMatrix m) {
return format(m, new StringBuffer(), new FieldPosition(0)).toString();
}
/**
* Formats a {@link RealMatrix} object to produce a string.
* @param matrix the object to format.
* @param toAppendTo where the text is to be appended
* @param pos On input: an alignment field, if desired. On output: the
* offsets of the alignment field
* @return the value passed in as toAppendTo.
*/
public StringBuffer format(RealMatrix matrix, StringBuffer toAppendTo,
FieldPosition pos) {
pos.setBeginIndex(0);
pos.setEndIndex(0);
// format prefix
toAppendTo.append(prefix);
// format rows
final int rows = matrix.getRowDimension();
for (int i = 0; i < rows; ++i) {
toAppendTo.append(rowPrefix);
for (int j = 0; j < matrix.getColumnDimension(); ++j) {
if (j > 0) {
toAppendTo.append(columnSeparator);
}
CompositeFormat.formatDouble(matrix.getEntry(i, j), format, toAppendTo, pos);
}
toAppendTo.append(rowSuffix);
if (i < rows - 1) {
toAppendTo.append(rowSeparator);
}
}
// format suffix
toAppendTo.append(suffix);
return toAppendTo;
}
/**
* Parse a string to produce a {@link RealMatrix} object.
*
* @param source String to parse.
* @return the parsed {@link RealMatrix} object.
* @throws MathParseException if the beginning of the specified string
* cannot be parsed.
*/
public RealMatrix parse(String source) {
final ParsePosition parsePosition = new ParsePosition(0);
final RealMatrix result = parse(source, parsePosition);
if (parsePosition.getIndex() == 0) {
throw new MathParseException(source,
parsePosition.getErrorIndex(),
Array2DRowRealMatrix.class);
}
return result;
}
/**
* Parse a string to produce a {@link RealMatrix} object.
*
* @param source String to parse.
* @param pos input/ouput parsing parameter.
* @return the parsed {@link RealMatrix} object.
*/
public RealMatrix parse(String source, ParsePosition pos) {
int initialIndex = pos.getIndex();
final String trimmedPrefix = prefix.trim();
final String trimmedSuffix = suffix.trim();
final String trimmedRowPrefix = rowPrefix.trim();
final String trimmedRowSuffix = rowSuffix.trim();
final String trimmedColumnSeparator = columnSeparator.trim();
final String trimmedRowSeparator = rowSeparator.trim();
// parse prefix
CompositeFormat.parseAndIgnoreWhitespace(source, pos);
if (!CompositeFormat.parseFixedstring(source, trimmedPrefix, pos)) {
return null;
}
// parse components
List> matrix = new ArrayList>();
List rowComponents = new ArrayList();
for (boolean loop = true; loop;){
if (!rowComponents.isEmpty()) {
CompositeFormat.parseAndIgnoreWhitespace(source, pos);
if (!CompositeFormat.parseFixedstring(source, trimmedColumnSeparator, pos)) {
if (trimmedRowSuffix.length() != 0 &&
!CompositeFormat.parseFixedstring(source, trimmedRowSuffix, pos)) {
return null;
} else {
CompositeFormat.parseAndIgnoreWhitespace(source, pos);
if (CompositeFormat.parseFixedstring(source, trimmedRowSeparator, pos)) {
matrix.add(rowComponents);
rowComponents = new ArrayList();
continue;
} else {
loop = false;
}
}
}
} else {
CompositeFormat.parseAndIgnoreWhitespace(source, pos);
if (trimmedRowPrefix.length() != 0 &&
!CompositeFormat.parseFixedstring(source, trimmedRowPrefix, pos)) {
return null;
}
}
if (loop) {
CompositeFormat.parseAndIgnoreWhitespace(source, pos);
Number component = CompositeFormat.parseNumber(source, format, pos);
if (component != null) {
rowComponents.add(component);
} else {
if (rowComponents.isEmpty()) {
loop = false;
} else {
// invalid component
// set index back to initial, error index should already be set
pos.setIndex(initialIndex);
return null;
}
}
}
}
if (!rowComponents.isEmpty()) {
matrix.add(rowComponents);
}
// parse suffix
CompositeFormat.parseAndIgnoreWhitespace(source, pos);
if (!CompositeFormat.parseFixedstring(source, trimmedSuffix, pos)) {
return null;
}
// do not allow an empty matrix
if (matrix.isEmpty()) {
pos.setIndex(initialIndex);
return null;
}
// build vector
double[][] data = new double[matrix.size()][];
int row = 0;
for (List rowList : matrix) {
data[row] = new double[rowList.size()];
for (int i = 0; i < rowList.size(); i++) {
data[row][i] = rowList.get(i).doubleValue();
}
row++;
}
return MatrixUtils.createRealMatrix(data);
}
}