Displaying 2 results from an estimated 2 matches for "newbon".
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newbox
2009 Apr 01
3
How to prevent inclusion of intercept in lme with interaction
...e, I feel ashamed that I cannot get this to work.
Maybe it's a syntax problem, but possibly a lack of understanding.
We have growth curves of new dental bone that can well be modeled by a
linear growth curve, for two different treatments and several subjects as
random parameter. By definition, newbone is zero at t=0, so I tried to force
the curve through 0. In Pinheiro/Bates, this is done by including the -1
term, and it works well when treatment is not included (newbone~t-1), but
seems to have no effect in (newone ~ t*treat-1).
What's wrong? Some bracket missing? I tried a few variants....
2011 Dec 21
3
NEWTON ALGORITHM
...x)
return(out)
}
## 1ST DERIVATIVE
fp=function(x){
out=(2)*(x^2)*exp(x^3)-(10/x)
return(out)
}
## 2ND DERIVATIVE
fpp=function(x){
out=(4)*(x)*exp(x^3)+(6)*(x^4)*exp(x^3)+(10/x^2)
return(out)
}
I am trying to find the "zero" of "fp",my 1st derivative, with my newton
algorithm:
newbon=function(x0,epsi,f,fp){
## where "a" corresponds to x^n et
## "b" corresponds to x^n+1
## We are looking for x^n+1 such that f(x^n+1)=0
## NB: fp(a)*(a-b)=f(a) when f(b)=0
a=x0
b=(fp(a)*a-f(a))/fp(a)
while(abs(-fp(a)*(b-a))>epsi){
a=b
b=(fp(a)*a-f(a))/fp(a)
}
o...