R help - Aug 2005 - interpolation function

On Fri, 2005-05-08 at 12:12 +0000,   wrote:
> Hi,
> I have a sparse matrix.I want to fill values into the entries whose value 
> is 0.The new generated values should come from the interpolation of the 
> values have existed.Does R provide such interpolation functions which 
> operate on Matrix, for example ,such a matrix below
>  0  0  0  0  2.3  0 0  0  0 
>  0  0 3.1 0   0   0 0 1.4 0
>  0  0  0  0   0   0 0  0  0
> 1.1 0  0  0   0   0 0  0  0
>  0  0  0  4   0   0 0  0  6
>  0  0  0  0   0   0 0  0  0
>  0  0  0  0   0   7 0  0  0
>  0  3  0  0   0   0 6  0  0
>  0  0  0  0   9   0 0  0  0
> thanks a lot
> hao wu
Does this look like an answer? If anyone knows a better way please tell
me.
> d<-c(0,2,3,2,0,3,4,0,0,0,0,0)
> d.mat<-matrix(data=d,nrow=4,ncol=3,byrow=TRUE)
> for(i in 1:length(d.mat[1,])){
+ d.mat[,i][d.mat[,i]==0]<-mean(d.mat[,i][d.mat[,i]>0])
+ }

Thanks
Tom

Hi,
I have a sparse matrix.I want to fill values into the entries whose value 
is 0.The new generated values should come from the interpolation of the 
values have existed.Does R provide such interpolation functions which 
operate on Matrix, for example ,such a matrix below
 0  0  0  0  2.3  0 0  0  0 
 0  0 3.1 0   0   0 0 1.4 0
 0  0  0  0   0   0 0  0  0
1.1 0  0  0   0   0 0  0  0
 0  0  0  4   0   0 0  0  6
 0  0  0  0   0   0 0  0  0
 0  0  0  0   0   7 0  0  0
 0  3  0  0   0   0 6  0  0
 0  0  0  0   9   0 0  0  0
thanks a lot
hao wu

What you intend strikes me as being pretty silly.  Do not expect R to
work magic for you.  Even if there were such a function as you desire
in R, the results it would give would be effectively meaningless for
data such as you exhibited.

			cheers,

				Rolf Turner
				rolf at math.unb.ca

I do not understand your question. If this was not a sparse matrix, then
I would have asked you refer into the missing value literature. Even
there, people generally remove any columns/rows that have too many
missing values to avoid unreliable results. 

And since this is a sparse matrix, you are going to have too many
missing values on all rows and columns. I could be wrong but if I am,
someone will tell me that soon enough.

Regards, Adai



On Fri, 2005-08-05 at 12:12 +0000,   wrote:
> Hi,
> I have a sparse matrix.I want to fill values into the entries whose value 
> is 0.The new generated values should come from the interpolation of the 
> values have existed.Does R provide such interpolation functions which 
> operate on Matrix, for example ,such a matrix below
>  0  0  0  0  2.3  0 0  0  0 
>  0  0 3.1 0   0   0 0 1.4 0
>  0  0  0  0   0   0 0  0  0
> 1.1 0  0  0   0   0 0  0  0
>  0  0  0  4   0   0 0  0  6
>  0  0  0  0   0   0 0  0  0
>  0  0  0  0   0   7 0  0  0
>  0  3  0  0   0   0 6  0  0
>  0  0  0  0   9   0 0  0  0
> thanks a lot
> hao wu
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html

I don't know if what Hao wanted to do is to hang himself, but if so, perhaps
here is one possible rope:
> idx <- which(m > 0, arr.ind=TRUE)
> m.nz <- m[idx]
> library(akima)
> (m.int <- interp.new(idx[,1], idx[,2], m.nz, xo=1:9, yo=1:9,
extrap=TRUE))
$x
[1] 1 2 3 4 5 6 7 8 9

$y
[1] 1 2 3 4 5 6 7 8 9

$z
              [,1]      [,2]      [,3]       [,4]       [,5]       [,6]
[,7]
 [1,]   57.1356740  55.18522 38.413800  18.086957   2.300000   0.737908  22.
544616
 [2,]   18.8241001  19.35348  3.100000 -20.355403 -41.610566 -51.308028 -40.
090327
 [3,]    3.2234619   8.63630 -5.312670 -29.221287 -53.732091 -69.487619 -67.
130408
 [4,]    1.1000000  13.75521  4.290890 -17.935507 -43.566514 -63.244671 -67.
612515
 [5,]    3.2013295  25.25298 22.408739   4.000000 -20.615776 -42.081126 -51.
038588
 [6,]    0.2005624  33.62766 39.538938  27.083292   5.618185 -15.498922 -26.
910566
 [7,]  -17.2478151  29.37731 46.179546  41.812431  25.633428   7.000000  -4.
730390
 [8,]  -58.4893169   3.00000 32.828625  38.685475  29.928013  15.913700   6.
000000
 [9,] -130.5161684 -53.43667 -9.550716   8.258617   9.000000   1.817369  -3.
604296
             [,8]       [,9]
 [1,]  76.7287988 170.407375
 [2,]   1.4000000  80.913745
 [3,] -37.3029968  28.876027
 [4,] -47.3125835   6.953079
 [5,] -38.1307000   6.000000
 [6,] -19.2592860  16.750369
 [7,]  -0.2080329  29.451691
 [8,]   9.3350825  34.229953
 [9,]   0.8303142  21.211142

Note how wild the interpolated/extrapolated values can be...

Andy

> From: Adaikalavan Ramasamy
> 
> I do not understand your question. If this was not a sparse 
> matrix, then
> I would have asked you refer into the missing value literature. Even
> there, people generally remove any columns/rows that have too many
> missing values to avoid unreliable results. 
> 
> And since this is a sparse matrix, you are going to have too many
> missing values on all rows and columns. I could be wrong but if I am,
> someone will tell me that soon enough.
> 
> Regards, Adai
> 
> 
> 
> On Fri, 2005-08-05 at 12:12 +0000, 佄佲 侁伝 wrote:
> > Hi,
> > I have a sparse matrix.I want to fill values into the 
> entries whose value 
> > is 0.The new generated values should come from the 
> interpolation of the 
> > values have existed.Does R provide such interpolation 
> functions which 
> > operate on Matrix, for example ,such a matrix below
> >  0  0  0  0  2.3  0 0  0  0 
> >  0  0 3.1 0   0   0 0 1.4 0
> >  0  0  0  0   0   0 0  0  0
> > 1.1 0  0  0   0   0 0  0  0
> >  0  0  0  4   0   0 0  0  6
> >  0  0  0  0   0   0 0  0  0
> >  0  0  0  0   0   7 0  0  0
> >  0  3  0  0   0   0 6  0  0
> >  0  0  0  0   9   0 0  0  0
> > thanks a lot
> > hao wu
> > 
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
>