问代码从Matlab到C#的转换
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Stack Overflow用户

提问于 2017-09-15 13:47:15

回答 1查看 82关注 0票数 1

我正在尝试将这个函数从matlab转换为C#

这些C#语句的等效matlab是什么？下面的C#部分显示了我不知道如何移植到C#的matlab代码部分

   res(res == 0) = p * scale * unit(res == 0);
   W = min(unit, scale * p * (abs(res)).^ (-1));

整个matlab部分，以及我移植它的尝试

function W = huber(res, scale, param)
% function W = huber(res, scale, param)
%
% computes Huber's weight function for robust regression:
% min( 1, param/(|res|/scale) )
% 
% arguments:
%       res:    vector of residuals
%       scale:  robust estimate of scale, such as MAD
%       param:  parameter of the Huber function; the
%           default value is 2.5.
%
% returns:
%       W:  the vector of Huber weights
%
%
% P.B. Stark  stark@stat.berkeley.edu
% 9 July 1997.

p = 2.5;        % default parameter
if (nargin == 3),
    if (param > 0),
        p = param;
    else
        error('parameter must be positive')
    end
end

unit = ones(size(res));
res(res == 0 ) = p*scale*unit(res==0);
W = min(unit, scale*p*(abs(res)).^(-1));
return;

C#码。

public static double Hueber(double[] residuals, double scale, double param)
{
        //Calculation of the mean estimate for a given range using Huber's weights
        //The Huber's function is defined as min( 1, param/(|residuals|/scale))
        //param: a given parameter - affects the range where weights = 1
        //residuals: deviation from the mean estimate (I used the median as the first approximation)
        //scale: estimate of variation. Some use 1.483*(median absolute deviation, or MAD,
        // of the deviations of the data from their median). I used std, i.e. dblAveVar
        //See http://www.stat.berkeley.edu/~stark/Preprints/Oersted/writeup.htm

        double p = 2.5;        //default parameter
        if (param > 0)
            p = param;
        else
            throw new Exception("parameter must be positive");

        double[] unit = Ones(residuals.Length);

        // What is the C# of this?
        //res(res == 0) = p * scale * unit(res == 0);
        //W = min(unit, scale * p * (abs(res)).^ (-1));

        return W;
    }

    public static double[] Ones(int length)
    {
        double[] ones = new double[length];

        ones.Populate(1.0);

        return ones;
    }

matlab

回答 1

Stack Overflow用户

回答已采纳

发布于 2017-09-15 14:20:55

//res(res == 0) = p * scale * unit(res == 0);
//W = min(unit, scale * p * (abs(res)).^ (-1));

代码如下：

public static double Hueber(double[] residuals, double scale, double param)
{
  double p = 2.5;        //default parameter
  if (param > 0)
     p = param;
  else
     throw new Exception("parameter must be positive");

  for ( int i = 0; i < residuals.Length ; i++) {
     if ( residuals[i] == 0) {
         residuals[i] = p * scale * 1;  // res(res == 0 ) = p*scale*unit(res==0)
     }
     // Then we can do smae step in this loop W = min(unit, scale*p*(abs(res)).^(-1))
     residuals[i] = Math.Min(1, scale*p*Math.Abs(1/residuals[i]));
  }

  return residuals; // w = residuals[]
  }