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Cleanup SFINAE in Array/Matrix(initializer_list) ctors and minor doc editing.

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Gael Guennebaud
2019-01-22 17:08:47 +01:00
parent db152b9ee6
commit 80f81f9c4b
10 changed files with 109 additions and 97 deletions
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doc/TutorialMatrixClass.dox
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@@ -101,38 +101,39 @@ Matrix3f a(3,3);
\endcode
and is a no-operation.
Additionally, we also offer some constructors to initialize the coefficients of small fixed-size vectors up to size 4:
Matrices and vectors can also be initialized from lists of coefficients.
Prior to C++11, this feature is limited to small fixed-size column or vectors up to size 4:
\code
Vector2d a(5.0, 6.0);
Vector3d b(5.0, 6.0, 7.0);
Vector4d c(5.0, 6.0, 7.0, 8.0);
\endcode
If C++11 is enabled, matrices can be constructed and initialized using initializer lists. In the case of fixed-sized vectors
and rowvectors a simple initializer list can be passed:
If C++11 is enabled, fixed-size column or row vectors of arbitrary size can be initialized through a single initializer list (\link Matrix::Matrix(const std::initializer_list<Scalar>&) details \endlink):
\code
Vector2i a {1, 2}; // A vector containing the elements {1, 2}
Matrix<int, 4, 1> b {1, 2, 3, 4}; // A row-vector containing the elements {1, 2, 3, 4}
Matrix<int, 1, 4> c {1, 2, 3, 4}; // A vector containing the elements {1, 2, 3, 4}
Vector2i a {1, 2}; // A column vector containing the elements {1, 2}
Matrix<int, 5, 1> b {1, 2, 3, 4, 5}; // A row-vector containing the elements {1, 2, 3, 4, 5}
Matrix<int, 1, 5> c {1, 2, 3, 4, 5}; // A column vector containing the elements {1, 2, 3, 4, 5}
\endcode
In the case of fixed or dynamically sized matrices an initializer list containing an initializer list for each row
can be passed. If the matrix is fixed-sized, the number of elements that are passed must match the dimensions.
In the general case of matrices and vectors with either fixed or runtime sizes,
coefficients have to be grouped by rows and passed as an initializer list of initializer list (\link Matrix::Matrix(const std::initializer_list<std::initializer_list<Scalar>>&) details \endlink):
\code
MatrixXi a {
MatrixXi a { // construct a 2x2 matrix
{1, 2}, // first row
{3, 4} // second row
};
Matrix<double, 2, 3> b {
{2.0, 3.0, 4.0},
{5.0, 6.0, 7.0},
{2, 3, 4},
{5, 6, 7},
};
\endcode
In the case of vectors and rowvectors, the following shorthand notation can be used:
For column or row vectors, implicit transposition is allowed.
This means that a column vector can be initialized from a single row:
\code
VectorXd a {{1.5, 2.5, 3.5}}; // A vector with 3 rows
RowVectorXd b {{1.0, 2.0, 3.0, 4.0}}; // A rowvector with 4 columns
VectorXd a {{1.5, 2.5, 3.5}}; // A column-vector with 3 coefficients
RowVectorXd b {{1.0, 2.0, 3.0, 4.0}}; // A row-vector with 4 coefficients
\endcode
\section TutorialMatrixCoeffAccessors Coefficient accessors