log_derivative_lpridge

Source: R/utilities.R

Function to calculate the derivative of the drawdown with respect to the derivative of log time using local ridge regression of the measured data.

log_derivative_lpridge(t, s, return.pos = T, log = T)

Arguments

t

Numeric vector with the time
s

Numeric vector with the drawdown
return.pos

Logical flag to return only the positive values of the log-derivative (default = TRUE)
log

Logical flag to indicate that natural logarithm (a log to the base e) is used in the derivative calculation (default = TRUE). Logarithm to the base 10 is used if FALSE.

Value

A list with

  • x: Numeric vector with the x coordinates where the log-derivative is evaluated

  • y: Numeric vector with the value of the log-derivative

  • res: A LPRIDGE Regression object

See also

Other log_derivative functions: log_derivative_bourdet, log_derivative_central, log_derivative_horner, log_derivative_kernelreg, log_derivative_locpol, log_derivative_lokern, log_derivative_smoothspline, log_derivative_spane, log_derivative_spline, log_derivative

Examples

data(boulton)
t <- boulton$t
s <- boulton$s
ptest <- pumping_test('Well1', Q = 0.03, r = 20, t = t, s = s)
#
dptest.lp <- log_derivative_lpridge(ptest$t, ptest$s)
plot(t, s, type = "p", log = "xy", ylim = c(1e-3,2))
points(dptest.lp$x, dptest.lp$y, col = "red")