[R] help writing for loop

Jessica Schedlbauer jschedlb at fiu.edu
Wed Nov 25 19:43:59 CET 2009


Hi, 

I’d like to ask for some help in writing a loop.  My situation is the following:

I have a matrix (matrix.A) containing 3 columns and 100 rows.  The columns represent parameter estimates a, b, and c.  The rows contain different values for these parameter estimates.  Each row is unique.

I want to insert these parameter estimates into a model (say, y = a + bx + cx^2) and solve for y given a separate matrix (matrix.B) of x values (where x has a length of 1500).

I want to solve for y 100 times using each set of the parameter estimates in matrix.A once.

At present my code looks like this and it only performs the first iteration.  

For (i in 1:length(matrix.A)) { y <- matrix.A$a[[i]] + matrixA$b[[i]] * matrix.B$x + matrixA$c[[i]] * matrix.B$x^2)

I have not been able to figure out how to loop through the rows of parameter estimates in matrix.A.  I am new to writing loops, so any assistance would be much appreciated.

Regards,
Jessica Schedlbauer




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