1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
5 // Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
6 //
7 // This Source Code Form is subject to the terms of the Mozilla
8 // Public License v. 2.0. If a copy of the MPL was not distributed
9 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
10
11 #ifndef EIGEN_IO_H
12 #define EIGEN_IO_H
13
14 namespace Eigen {
15
16 enum { DontAlignCols = 1 };
17 enum { StreamPrecision = -1,
18 FullPrecision = -2 };
19
20 namespace internal {
21 template<typename Derived>
22 std::ostream & print_matrix(std::ostream & s, const Derived& _m, const IOFormat& fmt);
23 }
24
25 /** \class IOFormat
26 * \ingroup Core_Module
27 *
28 * \brief Stores a set of parameters controlling the way matrices are printed
29 *
30 * List of available parameters:
31 * - \b precision number of digits for floating point values, or one of the special constants \c StreamPrecision and \c FullPrecision.
32 * The default is the special value \c StreamPrecision which means to use the
33 * stream's own precision setting, as set for instance using \c cout.precision(3). The other special value
34 * \c FullPrecision means that the number of digits will be computed to match the full precision of each floating-point
35 * type.
36 * - \b flags an OR-ed combination of flags, the default value is 0, the only currently available flag is \c DontAlignCols which
37 * allows to disable the alignment of columns, resulting in faster code.
38 * - \b coeffSeparator string printed between two coefficients of the same row
39 * - \b rowSeparator string printed between two rows
40 * - \b rowPrefix string printed at the beginning of each row
41 * - \b rowSuffix string printed at the end of each row
42 * - \b matPrefix string printed at the beginning of the matrix
43 * - \b matSuffix string printed at the end of the matrix
44 *
45 * Example: \include IOFormat.cpp
46 * Output: \verbinclude IOFormat.out
47 *
48 * \sa DenseBase::format(), class WithFormat
49 */
50 struct IOFormat
51 {
52 /** Default constructor, see class IOFormat for the meaning of the parameters */
53 IOFormat(int _precision = StreamPrecision, int _flags = 0,
54 const std::string& _coeffSeparator = " ",
55 const std::string& _rowSeparator = "\n", const std::string& _rowPrefix="", const std::string& _rowSuffix="",
56 const std::string& _matPrefix="", const std::string& _matSuffix="")
matPrefixIOFormat57 : matPrefix(_matPrefix), matSuffix(_matSuffix), rowPrefix(_rowPrefix), rowSuffix(_rowSuffix), rowSeparator(_rowSeparator),
58 rowSpacer(""), coeffSeparator(_coeffSeparator), precision(_precision), flags(_flags)
59 {
60 // TODO check if rowPrefix, rowSuffix or rowSeparator contains a newline
61 // don't add rowSpacer if columns are not to be aligned
62 if((flags & DontAlignCols))
63 return;
64 int i = int(matSuffix.length())-1;
65 while (i>=0 && matSuffix[i]!='\n')
66 {
67 rowSpacer += ' ';
68 i--;
69 }
70 }
71 std::string matPrefix, matSuffix;
72 std::string rowPrefix, rowSuffix, rowSeparator, rowSpacer;
73 std::string coeffSeparator;
74 int precision;
75 int flags;
76 };
77
78 /** \class WithFormat
79 * \ingroup Core_Module
80 *
81 * \brief Pseudo expression providing matrix output with given format
82 *
83 * \tparam ExpressionType the type of the object on which IO stream operations are performed
84 *
85 * This class represents an expression with stream operators controlled by a given IOFormat.
86 * It is the return type of DenseBase::format()
87 * and most of the time this is the only way it is used.
88 *
89 * See class IOFormat for some examples.
90 *
91 * \sa DenseBase::format(), class IOFormat
92 */
93 template<typename ExpressionType>
94 class WithFormat
95 {
96 public:
97
WithFormat(const ExpressionType & matrix,const IOFormat & format)98 WithFormat(const ExpressionType& matrix, const IOFormat& format)
99 : m_matrix(matrix), m_format(format)
100 {}
101
102 friend std::ostream & operator << (std::ostream & s, const WithFormat& wf)
103 {
104 return internal::print_matrix(s, wf.m_matrix.eval(), wf.m_format);
105 }
106
107 protected:
108 typename ExpressionType::Nested m_matrix;
109 IOFormat m_format;
110 };
111
112 namespace internal {
113
114 // NOTE: This helper is kept for backward compatibility with previous code specializing
115 // this internal::significant_decimals_impl structure. In the future we should directly
116 // call digits10() which has been introduced in July 2016 in 3.3.
117 template<typename Scalar>
118 struct significant_decimals_impl
119 {
runsignificant_decimals_impl120 static inline int run()
121 {
122 return NumTraits<Scalar>::digits10();
123 }
124 };
125
126 /** \internal
127 * print the matrix \a _m to the output stream \a s using the output format \a fmt */
128 template<typename Derived>
print_matrix(std::ostream & s,const Derived & _m,const IOFormat & fmt)129 std::ostream & print_matrix(std::ostream & s, const Derived& _m, const IOFormat& fmt)
130 {
131 if(_m.size() == 0)
132 {
133 s << fmt.matPrefix << fmt.matSuffix;
134 return s;
135 }
136
137 typename Derived::Nested m = _m;
138 typedef typename Derived::Scalar Scalar;
139
140 Index width = 0;
141
142 std::streamsize explicit_precision;
143 if(fmt.precision == StreamPrecision)
144 {
145 explicit_precision = 0;
146 }
147 else if(fmt.precision == FullPrecision)
148 {
149 if (NumTraits<Scalar>::IsInteger)
150 {
151 explicit_precision = 0;
152 }
153 else
154 {
155 explicit_precision = significant_decimals_impl<Scalar>::run();
156 }
157 }
158 else
159 {
160 explicit_precision = fmt.precision;
161 }
162
163 std::streamsize old_precision = 0;
164 if(explicit_precision) old_precision = s.precision(explicit_precision);
165
166 bool align_cols = !(fmt.flags & DontAlignCols);
167 if(align_cols)
168 {
169 // compute the largest width
170 for(Index j = 0; j < m.cols(); ++j)
171 for(Index i = 0; i < m.rows(); ++i)
172 {
173 std::stringstream sstr;
174 sstr.copyfmt(s);
175 sstr << m.coeff(i,j);
176 width = std::max<Index>(width, Index(sstr.str().length()));
177 }
178 }
179 s << fmt.matPrefix;
180 for(Index i = 0; i < m.rows(); ++i)
181 {
182 if (i)
183 s << fmt.rowSpacer;
184 s << fmt.rowPrefix;
185 if(width) s.width(width);
186 s << m.coeff(i, 0);
187 for(Index j = 1; j < m.cols(); ++j)
188 {
189 s << fmt.coeffSeparator;
190 if (width) s.width(width);
191 s << m.coeff(i, j);
192 }
193 s << fmt.rowSuffix;
194 if( i < m.rows() - 1)
195 s << fmt.rowSeparator;
196 }
197 s << fmt.matSuffix;
198 if(explicit_precision) s.precision(old_precision);
199 return s;
200 }
201
202 } // end namespace internal
203
204 /** \relates DenseBase
205 *
206 * Outputs the matrix, to the given stream.
207 *
208 * If you wish to print the matrix with a format different than the default, use DenseBase::format().
209 *
210 * It is also possible to change the default format by defining EIGEN_DEFAULT_IO_FORMAT before including Eigen headers.
211 * If not defined, this will automatically be defined to Eigen::IOFormat(), that is the Eigen::IOFormat with default parameters.
212 *
213 * \sa DenseBase::format()
214 */
215 template<typename Derived>
216 std::ostream & operator <<
217 (std::ostream & s,
218 const DenseBase<Derived> & m)
219 {
220 return internal::print_matrix(s, m.eval(), EIGEN_DEFAULT_IO_FORMAT);
221 }
222
223 } // end namespace Eigen
224
225 #endif // EIGEN_IO_H
226