Dear Kathie,
Try this:

X=matrix(seq(1,4), 2 , 2)
B=matrix(c(0.6,1.0,2.5,1.5) , 2 , 2)
list1 <- expand.grid( i=c(1,2) , y0=c(1,2) , j=c(1,2) )

apply(list1,1,function(x) {
                  i=x[1]
                 y0=x[2]
                  j=x[3]
                  y0*exp(X[i,]%*%B[,j])
                 }
)

# [1]     36.59823    181.27224     73.19647    362.54448   1096.63316
 59874.14172   2193.26632
# [8] 119748.28343

HTH,

Jorge



On Sun, Nov 16, 2008 at 7:49 PM, kathie <kathryn.lord2000@gmail.com> wrote:

>
> Dear R users...
>
> I made this by help of one of R users.
> _________________________________________________________________
>
> X=matrix(seq(1,4), 2 , 2)
> B=matrix(c(0.6,1.0,2.5,1.5) , 2 , 2)
>
> func <- function(i,y0,j) { y0*exp(X[i,]%*%B[,j]) }
> list1 <- expand.grid( i=c(1,2) , y0=c(1,2) , j=c(1,2) )
> results <- do.call( func , list1 )
> _________________________________________________________________
>
> > results
>              [,1]          [,2]         [,3]         [,4]          [,5]
> [,6]          [,7]          [,8]
> [1,]  36.59823  36.59823  36.59823  36.59823   1096.633   1096.633
> 1096.633   1096.633
> [2,] 181.27224 181.27224 181.27224 181.27224  59874.142  59874.142
> 59874.142  59874.142
> [3,]  73.19647  73.19647  73.19647  73.19647   2193.266   2193.266
> 2193.266   2193.266
> [4,] 362.54448 362.54448 362.54448 362.54448 119748.283 119748.283
> 119748.283 119748.283
> [5,]  36.59823  36.59823  36.59823  36.59823   1096.633   1096.633
> 1096.633   1096.633
> [6,] 181.27224 181.27224 181.27224 181.27224  59874.142  59874.142
> 59874.142  59874.142
> [7,]  73.19647  73.19647  73.19647  73.19647   2193.266   2193.266
> 2193.266   2193.266
> [8,] 362.54448 362.54448 362.54448 362.54448 119748.283 119748.283
> 119748.283 119748.283
> _________________________________________________________________
>
>
> However, I expected only this below as you imagine.
>              [,1]
> [1,]  36.59823
> [2,] 181.27224
> [3,]  73.19647
> [4,] 362.54448
>
>                [,5]
> [1,]    1096.633
> [2,]   59874.142
> [3,]    2193.266
> [4,]  119748.283
>
> That is, from "list1",
>
> y0*exp(X[i,]%*%B[,j])
> ------------------------------------
> 1*exp(X[1,]%*%B[,1]) = 36.59823
> 1*exp(X[2,]%*%B[,1]) = 181.27224
> 2*exp(X[1,]%*%B[,1]) = 73.19647
> 2*exp(X[2,]%*%B[,1]) = 362.54448
>
> 1*exp(X[1,]%*%B[,2]) = 1096.633
> 1*exp(X[2,]%*%B[,2]) = 59874.142
> 2*exp(X[1,]%*%B[,2]) = 2193.266
> 2*exp(X[2,]%*%B[,2]) = 119748.283
> ------------------------------------
>
> How could I find only 8 values?  Any suggestion will be greatly
> appreciated.
>
> Kathryn Lord
> --
> View this message in context:
> http://www.nabble.com/results-from-%22do.call%22-function-tp20532136p20532136.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@r-project.org mailing list
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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.
>

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