Inspired by Q Elbow / Knee Search on Curve I started playing with smooth.spline().
In particular, I want to imagine how a parameter df(degree of freedom) affects the approximation and the first and second derivatives. Note that this Q is not about approximation, but about a specific problem (or edge case) when visualizing with ggplot2.
First try: simple facet_grid()
library(ggplot2)
ggplot(ap, aes(x, y)) +
geom_point(data = dp, alpha = 0.2) +
geom_line() +
facet_grid(deriv ~ df, scales = "free_y", labeller = label_both) +
theme_bw()

dp- this is a data table containing data points for which approximation is requested, and ap- a data table with approximated data and derivatives (data are given below).
facet_grid() scales = "free_y" , . , "", . , " ".
"" coord_cartesian()
ggplot(ap, aes(x, y)) +
geom_point(data = dp, alpha = 0.2) +
geom_line() +
facet_grid(deriv ~ df, scales = "free_y", labeller = label_both) +
theme_bw() +
coord_cartesian(ylim = c(-200, 50))

3- . . , 1 .
coord_cartesian() ( , , rollise) . , ggplot?
: cowplot
cowplot:
g0 <- ggplot(ap[deriv == 0], aes(x, y)) +
geom_point(data = dp, alpha = 0.2) +
geom_line() +
facet_grid(deriv ~ df, scales = "free_y", labeller = label_both) +
theme_bw()
g1 <- ggplot(ap[deriv == 1], aes(x, y)) +
geom_line() +
facet_grid(deriv ~ df, scales = "free_y", labeller = label_both) +
theme_bw() +
coord_cartesian(ylim = c(-50, 50))
g2 <- ggplot(ap[deriv == 2], aes(x, y)) +
geom_line() +
facet_grid(deriv ~ df, scales = "free_y", labeller = label_both) +
theme_bw() +
coord_cartesian(ylim = c(-200, 100))
cowplot::plot_grid(g0, g1, g2, ncol = 1, align = "v")

,
facet_wrap() ?
facet_wrap() facet_grid():
ggplot(ap, aes(x, y)) +
# geom_point(data = dp, alpha = 0.2) + # this line causes error message
geom_line() +
facet_wrap(~ deriv + df, scales = "free_y", labeller = label_both, nrow = 3) +
theme_bw()

y , . , " " , coord_cartesian() .
,
geom_point(data = dp, alpha = 0.2)
gList ( (x = 0,5, y = 0,5, width = 1, height = 1, just = "center",: "grobs" "gList"
, , , .
library(data.table)
dp <- data.table(
x = c(6.6260, 6.6234, 6.6206, 6.6008, 6.5568, 6.4953, 6.4441, 6.2186,
6.0942, 5.8833, 5.7020, 5.4361, 5.0501, 4.7440, 4.1598, 3.9318,
3.4479, 3.3462, 3.1080, 2.8468, 2.3365, 2.1574, 1.8990, 1.5644,
1.3072, 1.1579, 0.95783, 0.82376, 0.67734, 0.34578, 0.27116, 0.058285),
y = 1:32,
deriv = 0)
ap <- rbindlist(
lapply(seq(2, length(dp$x), length.out = 4),
function(df) {
rbindlist(
lapply(0:2,
function(deriv) {
result <- as.data.table(
predict(smooth.spline(dp$x, dp$y, df = df), deriv = deriv))
result[, c("df", "deriv") := list(df, deriv)]
})
)
})
)