.getDefaultNlsValues {MicrobialGrowth}R Documentation

Default NLS values

Description

Gives default values for NLS regression from x and y values. The method of calculating default values differs depending on the amount of data available in y. Default values can be pre-set by providing them in the start, lower and upper arguments.

Usage

.getDefaultNlsValues(x, y, start = list(), lower = list(), upper = list())

Arguments

x

index series or time series.

y

values or list of values to regress (should not be logged, must be strictly greater than zero).

start

a named list of starting estimates. The coefficients specified in this list will not be calculated.

lower

a named list of lower bounds. The coefficients specified in this list will not be calculated.

upper

a named list of upper bounds. The coefficients specified in this list will not be calculated.

Details

default values are calculated as follows:

Note that it is possible, particularly when there is little data, that linear regression for start$mu is not possible, hence the presence of condition with THRESHOLD_FEW_DATA.

Value

the default values of start, lower and upper for NLS regression.

Examples

# Example data
x = c(0.00, 5.26, 10.53, 15.79, 21.05, 26.32, 31.58, 36.84, 42.11, 47.37, 52.63,
      57.89, 63.16, 68.42, 73.68, 78.95, 84.21, 89.47, 94.74, 100.00)
y = c(0.15, 0.15, 0.15, 0.16, 0.19, 0.26, 0.38, 0.58, 0.85, 1.18, 1.53, 1.86,
      2.15, 2.38, 2.55, 2.66, 2.78, 2.85, 2.89, 2.93)

# Simple example
values = .getDefaultNlsValues(x, y)
cat("N0=", values$start$N0, " with limits [", values$lower$N0, ", ", values$upper$N0,"]", sep="")
## N0=0.15 with limits [5.562685e-309, 1.4315]

# Example with specifying a starting value (which will therefore not be calculated)
values = .getDefaultNlsValues(x, y, start=list(N0=0.1))
cat("N0=", values$start$N0, " with limits [", values$lower$N0, ", ", values$upper$N0,"]", sep="")
## N0=0.1 with limits [5.562685e-309, 1.4315]

[Package MicrobialGrowth version 1.0.0 Index]