Hi,
Not sure if this is what you wanted:
?mat1<- as.matrix(read.table(text="
????? 33??????? 45??? 50
????? NA?????? NA?? 54
",sep="",header=FALSE))
mat2<- as.matrix(read.table(text="
24??????????????? 0.0000000??????? 0.0000000
0.0000000??????? 14??????????????? 0.0000000
0.0000000 0.0000000??????? 10
",sep="",header=FALSE))
?mat1%*%mat2
?# ??? V1? V2? V3
#[1,] 792 630 500
#[2,]? NA? NA? NA
library(Matrix)
mat1m<- as(mat1,"dgCMatrix")
?mat2m<- as(mat2,"dgCMatrix")
tcrossprod(mat1m,mat2m)
#2 x 3 sparse Matrix of class "dgCMatrix"
#???????????????
#[1,] 792 630 500
#[2,]? NA? NA 540
A.K.
>Hi,
>
>I'm looking to multiply two matrices together, one of which may
contain randomly placed NA values (i.e., there's no reason they will be
all in a row or >column), but I still want an output like the example
below: >
>Matrix 1
>[1,] ? ? ?33 ? ? ? ?45 ? ?50
>[2,] ? ? ? NA ? ? ? NA ? 54
>
>Matrix 2
>[1,] A1 ? ? ? ? ? ? ? ?0.0000000 ? ? ? ?0.0000000
>[2,] 0.0000000 ? ? ? ?A2 ? ? ? ? ? ? ? ?0.0000000
>[3,] 0.0000000 0.0000000 ? ? ? ?A3
>
>
>Result
>[1,] ? ? ?33*A1 ? ? ? 45*A2 ? ?50*A3
>[2,] ? ? ? NA ? ? ? NA ? ? ? ? ? ? ?(NA*0 +NA*0 +54*A3)=54*A3
>
>Simply doing Matrix1%*%Matrix2 doesn't give what I want for the
element in Row 2, Column 3 (it gives NA, which makes sense, but not sure
how to >do what I'd like it to do). ?For my purposes, Matrix 2 will
never have NA values, if that changes anything.
