baro5.Rd'baro5' allows specification of the baroreflex 5-parameter dose response function, under various constraints on the parameters.
baro5(fixed = c(NA, NA, NA, NA, NA), names = c("b1", "b2", "c", "d", "e"), method = c("1", "2", "3", "4"), ssfct = NULL)
| 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 order of the parameters is: b1, b2, c, d, e (see under 'Details'). |
| method | character string indicating the self starter function to use. |
| ssfct | a self starter function to be used. |
The five-parameter function given by the expression
$$ y = c + \frac{d-c}{1+f\exp(b1(\log(x)-\log(e))) + (1-f)\exp(b2(\log(x)-\log(e)))}$$
$$ f = 1/( 1 + \exp((2b1b2/|b1+b2|)(\log(x)-\log(e))))$$
If the difference between the parameters b1 and b2 is different from 0 then the function is asymmetric.
The value returned is a list containing the nonlinear model function, the self starter function and the parameter names.
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.