fredlund3: R optmisation of Fredlund three-parameter particle size...

In gowusu/vadose: The estimation of saturated hydraulic conductivity and soil water retention Curves in the vadose zone

Description

The function optimises 3 parameters of Fredlund et al (2000) particle size distribution function

Usage

fredlund3(data = NULL, D = NULL, fr = NULL, p = NULL, group = NULL,
  a = 1, m = 1, n = 1)

## Default S3 method:
fredlund3(data = NULL, D = NULL, fr = NULL, p = NULL,
  group = NULL, a = 1, m = 1, n = 1)

## S3 method for class 'fredlund3'
plot(x, main = "Particle Size Distribution Function",
  xlab = "Particle Diameter", ylab = "Fraction", ...)

## S3 method for class 'fredlund3'
coef(object, ...)

## S3 method for class 'fredlund3'
predict(object, D, ...)

Arguments

data	dataframe. It can contain data with column names of "time" and "I"
D	character. The corresponding diameter in the data.
fr	character. The corresponding fraction of the particles.
p	porosity[g/m^3]
group	character. The name of the group variables if the data is from different areas.
a	an initial value of 'a' parameter to be optimised
m	an initial value of 'm' parameter to be optimised
n	an initial value of 'n' parameter to be optimised
x	a return object of the function.
main	Title of the plot
xlab	x label of the plot
ylab	y label of the plot
...	Any other graphical parameter
object	Model output object

Value

• PD: predicted fraction by mass of particles passing a particular diameter

• sand: percentage of sand

• clay: percentage of clay

• silt: percentage of silt

• a: optimised a parameter

• m: optimised m parameter

• n: optimised n parameter

Author(s)

George Owusu

References

Fredlund, M. D., Fredlund, D. G., & Wilson, G. W. (2000). An equation to represent grain-size distribution. Can Geotech J, 65, 638-648.

See Also

zhuang3, zhuang4,lass3,logarithmic, logistic2, logistic3,logistic4,fredlund4, jaky,andersson,gompertz, haverkamp

Other Fredlund functions: fredlund4

Examples

data=read.csv(system.file("ext","sys","soil2.csv",package="vadose"))
single<- subset(data, ID=="30B20_1")
mod=fredlund3 (data=single,p="sand",D="D",fr="Sand.")
plot(mod)

#group simulation
mod2=fredlund3 (data=data,D="D",fr="FractionSand",group="ID")
mod2$coef
#generic function

gowusu/vadose documentation built on May 17, 2019, 7:59 a.m.