Hello,
>
> I must be missing something very obvious, but I just cannot see it.
>
The hardest to find errors.
Wrong manual calculation in t1, powers have precedence right to left and
before additions.
t1b <- 10^(params[1]-xx)^params[2]
t3b <- 1 + t1b
t4b <- t2/t3b
t5b <- params[4] + t4b
all.equal
On Wed, May 02, 2012 at 11:42:27AM -0400, Rajarshi Guha wrote:
> Hi, I'm running a calculation in two ways. The first way is to employ
> vectors and evaluate a function in one go. The second way is to break
> down the function into pieces and combine the pieces to the final
> answer.
>
> Algebraic
Your multistep approach corresponds to the following, which has one
more set of parentheses than you used
yy <- params[4] + (params[3] - params[4])/((1 + 10^(params[1]-xx))^params[2])
In R lingo, both of your approaches are vectorized and you probably won't find
a huge difference in speed betwee
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