soilphysics (version 5.0)

SSlbc: Self-Starting Nls Load Bearing Capacity Model

Description

A selfStart model that evaluates the Load Bearing Capacity (Dias Jr., 1994) function and its gradient. It has an initial attribute that creates initial estimates of the parameters b0 and b1.

Usage

SSlbc(theta, b0, b1)

Arguments

theta

a numeric vector of soil moisture values at which to evaluate the model.

b0

a numeric parameter.

b1

a numeric parameter.

Value

a numeric vector with the same length of theta. It is the value of the expression \(10^{(b0 + b1 * \theta)}\). Also, the gradient matrix with respect to the parameters is attached as an attribute named gradient.

References

Dias Junior, M. S. (1994). Compression of three soils under longterm tillage and wheel traffic. 1994. 114p. Ph.D. Thesis - Michigan State University, East Lansing.

See Also

getInitiallbc, fitlbc, selfStart, nls, sigmaP

Examples

# NOT RUN {
data(compaction)
attach(compaction)
ss <- SSlbc(Mois, 2.79, -2.33)
ss[1:50] # prediction
PS # original data of preconsolidation stress
ss # prediction and gradient

# End (not run)
# }