R help - Oct 2012 - Parameter Matrix

Hallo,
 I would like to run a model (differential equations)
with a whole bunch of parameter combinations.

I think the best way of doing this is to put the model
function into a loop and set a matrix with the parameters:
Each row will represent the parameters for one loop. 

I know how to compile such a matrix (via another loop,
or by using rbind etc.). However I hope you guys may have 
a much better solution compiling such a matrix very quick
and straightforward.

Example (very simple):

a <- 1:2
b <- 5
c <- seq(1,10,5)

The Matrix should be:

a	b	c
1	5	1
1	5	6
2	5	1
2	5	6


Any ideas?
Cheers,
Simeon

Hi,

Try this:
new1<-as.data.frame(expand.grid(a=a,b=b,c=c))
?mat1<-as.matrix(new1[order(new1$a),])
?row.names(mat1)<-1:nrow(mat1)
mat1
#? a b c
#1 1 5 1
#2 1 5 6
#3 2 5 1
#4 2 5 6
A.K.




----- Original Message -----
From: Simeon Lisovski <simeon.lisovski at me.com>
To: r-help at r-project.org
Cc: 
Sent: Sunday, October 21, 2012 7:05 PM
Subject: [R] Parameter Matrix

Hallo,
I would like to run a model (differential equations)
with a whole bunch of parameter combinations.

I think the best way of doing this is to put the model
function into a loop and set a matrix with the parameters:
Each row will represent the parameters for one loop. 

I know how to compile such a matrix (via another loop,
or by using rbind etc.). However I hope you guys may have 
a much better solution compiling such a matrix very quick
and straightforward.

Example (very simple):

a <- 1:2
b <- 5
c <- seq(1,10,5)

The Matrix should be:

a??? b??? c
1??? 5??? 1
1??? 5??? 6
2??? 5??? 1
2??? 5??? 6


Any ideas?
Cheers,
Simeon

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