Eigen实现matlab中的reshape

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已于 2022-06-01 11:46:11 修改 · 468 阅读

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于 2022-06-01 11:34:01 首次发布

本文详细介绍了Eigen库在3.4版本中如何进行矩阵重塑，包括2D视图的重塑和1D线性视图的创建。通过DenseBase::reshaped()函数，可以方便地将矩阵转换为不同尺寸的视图，而不改变原始数据。同时，也讨论了原地重排（resize）操作，需要注意其依赖于输入的存储顺序。示例代码展示了各种重塑和重排的方法及其效果。

https://eigen.tuxfamily.org/dox-devel/group__TutorialReshape.html

注意，需要Eigen3.4版本

Since the version 3.4, Eigen exposes convenient methods to reshape a matrix to another matrix of different sizes or vector. All cases are handled via the DenseBase::reshaped(NRowsType,NColsType) and DenseBase::reshaped() functions. Those functions do not perform in-place reshaping, but instead return a view on the input expression.

Reshaped 2D views 2维矩阵的重排

The more general reshaping transformation is handled via: reshaped(nrows,ncols). Here is an example reshaping a 4x4 matrix to a 2x8 one:

例子1

code:注意，默认是列优先，matlab的reshape是列优先

Matrix4i m = Matrix4i::Random();
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Here is m.reshaped(2, 8):" << endl << m.reshaped(2, 8) << endl;
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