Re: [R] R problem nls

2012-04-09 Thread Carlos Ortega
Hi, And regarding how to extend the nls algorithm to a larger dataset it is a question of indicating in the nls() functions which data.frame to use. In you example you were using a small set of x's ad y's, so if you want to use a large set put it in a new data.frame and pass it to nls(). And if y

Re: [R] R problem nls

2012-04-09 Thread Jean V Adams
Your formula could be simplified to y ~ 1 + a * exp(-b * x) Solve this equation for x x = ln[(y - 1)/a]/b Use this equation to find the intersection point at a given value of y. For example, when y = 1.01 x = ln(0.01/a)/b Jean Karen Vandepoel wrote on 04/09/2012 0

[R] R problem nls

2012-04-09 Thread Karen Vandepoel
Hi, I will try to explain what it is I need to do, how far I am in doing it yet and where my problem is: I have a lot of x,y values I need to fit a non linear function through. Subsequently, I need to find the intersection point of this fitted curve with y=1.01 The problem is I have a lot of val