baro5 {drc} | R Documentation |
'baro5' allows specification of the baroreflex 5-parameter dose response function, under various constraints on the parameters.
baro5(lowerc = c(-Inf, -Inf, -Inf, -Inf, -Inf), upperc = c(Inf, Inf, Inf, Inf, Inf), fixed = c(NA, NA, NA, NA, NA), names = c("b1", "b2", "c", "d", "e"), scaleDose = TRUE, useDer = FALSE)
lowerc |
numeric vector. The lower bound on parameters. Default is minus infinity. |
upperc |
numeric vector. The upper bound on parameters. Default is plus infinity. |
fixed |
numeric vector. Specifies which parameters are fixed and at what value they are fixed. NAs for parameter that are not fixed. |
names |
a vector of character strings giving the names of the parameters (should not contain ":"). The default is reasonable (see under 'Usage'). The order of the parameters is: b1, b2, c, d, e (see under 'Details'). |
scaleDose |
logical. If TRUE dose values are scaled around 1 during estimation; this is required for datasets where all dose values are small. |
useDer |
logical. If TRUE derivatives are supplied, otherwise they are not supplied. Not implemented. |
The five-parameter function given by the expression
y = c + frac{d-c}{1+fexp(b1(log(x)-log(e))) + (1-f)exp(b2(log(x)-log(e)))}
f = 1/( 1 + exp((2b1b2/|b1+b2|)(log(x)-log(e))))
If the difference between the parameters b1 and b2 is different from 0 then the function is asymmetric.
The value returned by the 'baro5' is a list with the following components
fct |
The dose response function. |
ssfct |
The self starter function. |
deriv1 |
The first derivative. Not available. |
deriv2 |
The second derivative. Not available. |
lowerc |
The lower bounds on the parameters. |
upperc |
The upper bounds on the parameters. |
edfct |
The ED function. Not available. |
sifct |
The SI function. Not available. |
Christian Ritz
Ricketts, J. H. and Head, G. A. (1999) A five-parameter logistic equation for investigating asymmetry of curvature in baroreflex studies. Am. J. Physiol. (Regulatory Integrative Comp. Physiol. 46), 277, 441–454.
## See the example for the heartrate dataset