search for: dx2x

Displaying 3 results from an estimated 3 matches for "dx2x".

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2012 Nov 16
1
How to get the result of eval()
I just discover the deriv function but I have a minor problem at the end when using its result: For example: dx2x <- deriv(~ A*x^2, "x") ; dx2x # it works fine: # expression({ # .value <- A * x^2 # .grad <- array(0, c(length(.value), 1L), list(NULL, c("x"))) # .grad[, "x"] <- A * (2 * x) # attr(.value, "gradient") <- .grad # .value # }) A <- 3 x <-...
2003 Nov 14
3
Expressions and Functions
Dear R People: When the D function is used for a symbolic derivative, an expression is returned, which is fine. How do you change that expression to a function, please? I've been experimenting with substitute and deparse, but no success yet. This is R 1.8.0 for Windows. thanks in advance for the help! Sincerely, Erin Hodgess mailto: hodgess at gator.uhd.edu
2009 May 10
4
Partial Derivatives in R
Quick question: Which function do you use to calculate partial derivatives from a model equation? I've looked at deriv(), but think it gives derivatives, not partial derivatives. Of course my equation isn't this simple, but as an example, I'm looking for something that let's you control whether it's a partial or not, such as: somefunction(y~a+bx, with respect to x,