From ligges at statistik.tu-dortmund.de  Fri Jul 15 15:10:21 2011
From: ligges at statistik.tu-dortmund.de (Uwe Ligges)
Date: Fri, 15 Jul 2011 15:10:21 +0200
Subject: [Rd] fuzzy c-means algorithm in e1071
In-Reply-To: <1310717482041-3669374.post@n4.nabble.com>
References: <1310717482041-3669374.post@n4.nabble.com>
Message-ID: <4E203C3D.10406@statistik.tu-dortmund.de>

Since you are talking about a contributed package: Please send feature 
requests to the package maintainer:

 > maintainer("e1071")
[1] "Friedrich Leisch <Friedrich.Leisch at R-project.org>"


It is even a better idea to send him your own code suggestions so that 
it will be quicker to add the requested features to the package.

Best,
Uwe Ligges




On 15.07.2011 10:11, Tim Smyth wrote:
> I was wondering if it was possible to add an extra option to the cmeans
> function please?  In a recent paper by Moore et al.,(2009) they state:
>
> "The fuzzy membership function is: 1 - F(Z2), where Z2 is a squared
> Mahalanobis distance and F is a cumulative chi-square distribution.  The
> Mahalanobis distance is the multivariate equivalent of the standardised
> random variable Z = (X - M)/S, which is the distance of the univariate
> random variable X from its mean M normalised by the standard deviation S.
> In other words, the Mahalanobis distance is a weighted form of the
> Euclidean, and is preferable because it incorporates the shape of the the
> distribution of points around the cluster centre (i.e., the geometric shape
> of the point cloud expressed in terms of variance). The fuzzy membership
> ranges from 0 to 1 ..."
>
> so as well as having a dist = "euclidean" option, would it be possible to
> have a dist = "mahalanobis" option please?  I realise that this is quite an
> ask - you could even point me in the right direction of where to start
> editing code and getting it compiled on my own machine.
>
> Tim Smyth
>
> ref: T.S. Moore et al. Remote Sensing of Environment 113 (2009) 2424-2430
>
> --
> View this message in context: http://r.789695.n4.nabble.com/fuzzy-c-means-algorithm-in-e1071-tp3669374p3669374.html
> Sent from the R devel mailing list archive at Nabble.com.
>
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[Rd] fuzzy c-means algorithm in e1071
Uwe Ligges