[R] Algebraic operation on the missing values

[Joanna Procelewska]

Thanks for the answer.

The problem is I have to perform a forward selection on the set and in every
step construct an orthonormal base for the subspace spanned on the selected
vectors. This means that I can use only the "full" vectors for the constructing
a base, or? 

Joanna

--- Petr Pikal <petr.pikal at precheza.cz> schrieb:

> Hi
> 
> see
> ?complete.cases and/or ?is.na for evaluating non missing entries. 
> 
> However in any operation in which you use NA value, result shall be 
> NA as you do not know what actually is NA.
> 
> HTH
> Petr
> 
> > Hi all,
> > 
> > I have a large set of descriptors, which are stored as the vectors,
> > each one containing about 450 elements. Now I have to perform some
> > algebraical operations on this set to eliminate the redundant ones.
> > The problem is, that not all vales in the vectors are known. Are there
> > any norm defined how should I process such vectors? Simple example:
> > having two vectors:
> > 
> > a      b
> > 3      4
> > 2      null
> > 3      6
> > 
> > I can imagine that a+b is [7 null 9]', but what about scalar product?
> > Is it null or have it a value? I don't want to replace missing values
> > with the concrete ones, but they significantly complicate my
> > computations. 
> > 
> > Does anyone know whether there are any ways to solve this problem?
> > Please share some experience. Really appreciate the help!
> > 
> > Sincerely,
> > 
> > Joanna
> > 
> > ______________________________________________
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> > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html and provide commented,
> > minimal, self-contained, reproducible code.
> 
> Petr Pikal
> petr.pikal at precheza.cz
> 
>