Dark (version 0.9.9)

Start: Start

Description

A function to build an array of starting parameters from a dark object.

Usage

Start(obj, Reps)

Value

Output is an array of seven columns and number of rows = 'Reps'.

Arguments

obj

A dark object

Reps

The number of rows in the array.

Author

Jeremiah MF Kelly

Mumac Ltd, SK7 6NR, GB

Details

The array of starting parameters is built from the time and threshold data in the object, obj.

Each parameter is assumed to have a possible range given the data.

Each range is constructed as follows; the time points; alpha (cone-rod transition \(\alpha\) minutes) and beta (rod-rod transition \(\beta\) minutes) are assumed to fall in the first and second halves of the time data respectively (obj$time).

The cone threshold is assumed to be in the upper half of the threshold data (obj$thrs log units). The cone coefficient (log units) or threshold at time zero is presumed to be positive and the same values are used for the time constants (\(tau\) minutes).

The rate of rod recovery S2, and the combined parameter -(S2 + S3) are ranged between -0.6 and 0 log units/minute.

These ranges of possible values are complied into an array by sampling without replacement from each range for each parameter.

Examples

set.seed(1234)
tmp<-TestData(0:20)
Start(tmp, 10)