Matlab重新缩放命令的本征等效项

问题描述

我想在Eigen中重新创建Matlab重新缩放命令

I'd like to recreate the Matlab rescale command in Eigen

我尝试翻译，但不确定。我的Eigen知识仍然太有限了……

I've tried to translate but not sure about it. My Eigen knowledge is too limited still...

  auto rescale = [&](
    Eigen::MatrixXd mat,
    Eigen::VectorXd inmin,
    Eigen::VectorXd inmax,
    Eigen::VectorXd l,
    Eigen::VectorXd u
    ) -> Eigen::MatrixXd {

    auto val = l.array() + (
      ((mat - inmin).array()) / ((
        ((inmax - inmin).array()) * ((u - l).array())
      ).array())
    );

    return val;
  };

这可行吗？

推荐答案

否。您的尺寸不匹配。您正在混合 ArrayXd 和 ArrayXXd 。这更像您想要的，带有一个用于标量的版本和一个用于矢量的版本。调整逐行 / 逐行以匹配不同版本的matlab 重新缩放。

No. Your dimensions don't match. You're mixing ArrayXd and ArrayXXd. This is more like what you want, with a version for scalars and another for vectors. Adjust the rowwise/colwise to match the different versions of matlabs rescale.

#include <Eigen/Core>
#include <iostream>

int main()
{

    auto rescale = [&](
        Eigen::MatrixXd mat,
        double l,
        double u
        ) -> Eigen::MatrixXd {

        double min = mat.minCoeff();
        double max = mat.maxCoeff();
        auto val = l + (mat.array() - min) * ((u - l) / (max - min));
        return val;
    };

    Eigen::MatrixXd mat(4,4);
    Eigen::Map<Eigen::VectorXd>(mat.data(), mat.size()).setLinSpaced(1, mat.size());

    std::cout << mat << "\n\n";

    auto rescaled = rescale(mat, 2, 5);

    std::cout << rescaled << "\n\n";

    auto rescale2 = [&](
        Eigen::MatrixXd mat,
        Eigen::VectorXd l,
        Eigen::VectorXd u
        ) -> Eigen::MatrixXd {

        Eigen::ArrayXd  min = mat.colwise().minCoeff();
        Eigen::ArrayXd  max = mat.colwise().maxCoeff();
        auto val = l.array().replicate(1, mat.cols())
            + ((mat.array().rowwise() - min.transpose()).rowwise() *
               ((u - l).array() / (max - min)).transpose());
        return val;
    };

    Eigen::VectorXd mn, mx;

    mn.resize(mat.cols());
    mx.resize(mat.cols());

    mn.setConstant(1.3);
    mx << 2, 5, 6, 9;
    rescaled = rescale2(mat, mn, mx);

    std::cout << rescaled << "\n\n";



    return 0;
}

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