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I'm trying to print a vector field based on a matrix multiplication. The problem is that the function that will print values to make the matrix multiplication can only take a single number. When a range of number is put into the all.p function, the output is not usable to do the matrix multiplication. Is there a way to change all.p so that with multiple inputs, the matrix multiplication can still be valid, and the vector field can be computed? The code fails at the vectorfield function as this function with put the values into the range 0 to 1, but the all.p can't take multiple inputs.
geno.fit = matrix(c(0.791,1.000,0.834,
0.670,1.006,0.901,
0.657,0.657,1.067),
nrow = 3,
ncol = 3,
byrow = T)
all.p <- function(p) {
if (length(p)>1) {
stop("More numbers in input than expected")
}
P = p^2
PQ = 2*p*(1-p)
Q = (1-p)^2
return(list=c(P=P,PQ=PQ,Q=Q))
}
library(pracma)
f <- function(x, y) all.p(x) %*% geno.fit %*% all.p(y)
xx <- c(0, 1); yy <- c(0, 1)
vectorfield(fun = f, xlim = xx, ylim = yy, scale = 0.1)
for (xs in seq(0, 1, by = 0.25)) {
sol <- rk4(f, 0, 1, xs, 100)
lines(sol$x, sol$y, col="darkgreen")
}
grid()
I also tried to use a for loop.
f <- function(x, y, n = 16) {
space3 = matrix(NA,nrow = n,ncol = n)
for (i in 1:(length(x))) {
for (j in 1:(length(y))) {
# Calculate mean fitness
space3[i,j] = all.p(x[i]) %*% geno.fit %*% all.p(y[j])
}
}
return(space3)
}
xx <- c(0, 1); yy <- c(0, 1)
f(seq(0,1,length.out = 16), seq(0,1,length.out = 16))
vectorfield(fun = f, xlim = xx, ylim = yy, scale = 0.1)
Below is the code to make the gradient ascend (without the vectors).
library(fields) # for image.plot
res = 0.01
seq.x = seq(0,1,by = res)
space = outer(seq.x,seq.x,"*")
pace2 = space
for (i in 1:length(seq.x)) {
for (j in 1:length(seq.x)) {
space[i,j] = all.p(1-seq.x[i]) %*% geno.fit %*% all.p(1-seq.x[j])
}
}
round(t(space),3)
new.space = t(space)
image.plot(new.space)
by.text = 8
for (i in seq(1,length(seq.x),by = by.text)) {
for (j in seq(1,length(seq.x),by = by.text)) {
text(seq.x[i],seq.x[j],
labels = round(new.space[i,j],4),
cex = new.space[i,j]/2,
col = "black")
}
}
contour(new.space,ylim=c(1,0),add = T, nlevels = 50)
I was able to make the vector field function work, but it's not showing what I was expecting from the previous gradient ascend vector field:
How can the 2 be reconciled? (i.e., plotting the vectors on the gradient ascend image which would show the proper direction of the vectors in the steepest ascend)
Here is my solution:
library(fields) # for image.plot
library(plotly)
library(raster)
# Genotype fitness matrix -------------------------------------------------
geno.fit = matrix(c(0.791,1.000,0.834,
0.670,1.006,0.901,
0.657,0.657,1.067),
nrow = 3,
ncol = 3,
byrow = T)
# Resolution
res = 0.01
# Sequence of X
seq.x = seq(0,1,by = res)
# Make a matrix
space = outer(seq.x,seq.x,"*")
# Function to calculate the AVERAGE fitness for a given frequency of an allele to get the expected frequency of genotypes in a population
all.p <- function(p) { # Takes frequency of an allele in the population
if (length(p)>1) { # Has to be only 1 number
stop("More numbers in input than expected")
}
P = p^2 # Gets the AA
PQ = 2*p*(1-p) # gets the Aa
Q = (1-p)^2 # Gets the aa
return(list=c(P=P, # Return the values
PQ=PQ,
Q=Q))
}
# Examples
all.p(0)
all.p(1)
# Plot the matrix of all combinations of genotype frequencies
image.plot(space,
ylim=c(1.05,-0.05),
ylab= "Percentage of Chromosome EF of TD form",
xlab= "Percentage of Chromosome CD of BL form")
# Backup the data
space2 = space
# calculate the average fitness for EVERY combination of frequency of 2 genotypes
for (i in 1:length(seq.x)) {
for (j in 1:length(seq.x)) {
# Calculate mean fitness
space[i,j] = all.p(1-seq.x[i]) %*% geno.fit %*% all.p(1-seq.x[j])
}
}
# Show the result
round(t(space),3)
# Transform the space
new.space = t(space)
image.plot(new.space,
# ylim=c( 1.01,-0.01),
ylab= "Percentage of Chromosome EF of TD (Tidbinbilla) form",
xlab= "Percentage of Chromosome CD of BL (Blundell) form")
# Add the numbers to get a better sense of the average fitness values at each point
by.text = 8
for (i in seq(1,length(seq.x),by = by.text)) {
for (j in seq(1,length(seq.x),by = by.text)) {
text(seq.x[i],seq.x[j],
labels = round(new.space[i,j],4),
cex = new.space[i,j]/2,
col = "black") # col = "gray70"
}
}
# Add contour lines
contour(new.space,ylim=c(1,0),add = T, nlevels = 50)
# Plotly 3D graph --------------------------------------------------------
# To get the 3D plane in an INTERACTIVE graph
xyz=cbind(expand.grid(seq.x,
seq.x),
as.vector(new.space))
plot_ly(x = xyz[,1],y = xyz[,2],z = xyz[,3],
color = xyz[,3])
# Vector field on the Adaptive landscape ----------------------------------
library(tidyverse)
library(ggquiver)
raster2quiver <- function(rast, aggregate = 50, colours = terrain.colors(6), contour.breaks = 200)
{
names(rast) <- "z"
quiv <- aggregate(rast, aggregate)
terr <- terrain(quiv, opt = c('slope', 'aspect'))
quiv$u <- -terr$slope[] * sin(terr$aspect[])
quiv$v <- -terr$slope[] * cos(terr$aspect[])
quiv_df <- as.data.frame(quiv, xy = TRUE)
rast_df <- as.data.frame(rast, xy = TRUE)
print(ggplot(mapping = aes(x = x, y = y, fill = z)) +
geom_raster(data = rast_df, na.rm = TRUE) +
geom_contour(data = rast_df,
aes(z=z, color=..level..),
breaks = seq(0,3, length.out = contour.breaks),
size = 1.4)+
scale_color_gradient(low="blue", high="red")+
geom_quiver(data = quiv_df, aes(u = u, v = v), vecsize = 1.5) +
scale_fill_gradientn(colours = colours, na.value = "transparent") +
theme_bw())
return(quiv_df)
}
r <-raster(
space,
xmn=range(seq.x)[1], xmx=range(seq.x)[2],
ymn=range(seq.x)[1], ymx=range(seq.x)[2],
crs=CRS("+proj=utm +zone=11 +datum=NAD83")
)
# Draw the adaptive landscape
raster2quiver(rast = r, aggregate = 2, colours = tim.colors(100))
Not exactly what I wanted, but it does what I was looking for!
How can I make this red polygon partially transparent so I can see the points underneath it?
library(ks)
set.seed(1234)
x <- runif(1000) + -150
y <- runif(1000) + 20
my.data <- data.frame(x,y)
my.matrix <- as.matrix(my.data)
my_gps_hpi <- Hpi(x = my.matrix, pilot = "samse", pre = "scale")
my.fhat <- kde(x = my.matrix, compute.cont = TRUE, h = my_gps_hpi,
xmin = c(min(my.data$x), min(my.data$y)),
xmax = c(max(my.data$x), max(my.data$y)),
bgridsize = c(100, 100))
my.contours <- c(75)
contourLevels(my.fhat, cont = my.contours)
contourSizes(my.fhat, cont = my.contours, approx = TRUE)
plot(my.data$x, my.data$y)
plot(my.fhat, lwd = 3, display = "filled.contour", cont = my.contours, add = TRUE)
png(file="transparent_polygon_June21_2021.png")
plot(my.data$x, my.data$y)
plot(my.fhat, lwd = 3, display = "filled.contour", cont = my.contours, add = TRUE)
dev.off()
I think I have figured out a solution by digging around in the source code in the file kde.R.
I made several changes to my code.
Changed my.fhat to fhat because the source code might want fhat.
Changed my.contours to contours for the same reason.
Changed contourLevels(my.fhat, cont = my.contours) to hts <- contourLevels(fhat, cont = contours) for the same reason.
Extracted the col.fun from the source code and changed it to return the color of my choice: col.fun <- function(n) {rgb(255, 0, 0, 127, maxColorValue=255)}.
Modified the plot statement to that shown in the code below.
Here is the modified R code:
setwd('C:/Users/mark_/Documents/ctmm/density_in_R/')
set.seed(1234)
library(ks)
x <- runif(1000) + -150
y <- runif(1000) + 20
my.data <- data.frame(x,y)
my.matrix <- as.matrix(my.data)
gps_hpi <- Hpi(x = my.matrix, pilot = "samse", pre = "scale")
fhat <- kde(x = my.matrix, compute.cont = TRUE, h = gps_hpi,
xmin = c(min(my.data$x), min(my.data$y)),
xmax = c(max(my.data$x), max(my.data$y)),
bgridsize = c(100, 100))
contours <- c(75)
hts <- contourLevels(fhat, cont = contours)
contourSizes(fhat, cont = contours, approx = TRUE)
col.fun <- function(n) {rgb(255, 0, 0, 127, maxColorValue=255)}
col.fun(1)
plot(fhat, lwd = 3, display = "filled.contour", cont = contours, col.fun = col.fun(1), drawpoints=TRUE)
png(file="transparent_polygon_June22_2021.png")
plot(fhat, lwd = 3, display = "filled.contour", cont = contours, col.fun = col.fun(1), drawpoints=TRUE)
dev.off()
I needed to include in the code below, a vertical line,
for example, in position x = 5 and that all points smaller than 5 have another color,
for example blue.
The values of a variable can be read from the x-axis, and the y-axis shows the order of the observations in the variable (from bottom to top). Isolated points as the far ends, and on either side in a plot, suggest potentional outliers
Thanks
library(dplyr)
library(lattice)
n = 1000
df <- tibble(
xx1 = runif(n, min = 3, max = 10),
xx2 = runif(n, min = 3, max = 10),
xx3 = runif(n, min = 3, max = 10)
)
MyVar <- c("xx1","xx2","xx3")
MydotplotBR <- function(DataSelected){
P <- dotplot(as.matrix(as.matrix(DataSelected)),
groups=FALSE,
strip = strip.custom(bg = 'white',
par.strip.text = list(cex = 1.2)),
scales = list(x = list(relation = "same",tck = 1,
draw = TRUE, at=seq(0,10,1)),x=list(at=seq),
y = list(relation = "free", draw = FALSE),
auto.key = list(x =1)),
col=10,
axes = FALSE,
cex = 0.4, pch = 5,
xlim=c(0,10),
xlab = list(label = "Variable Value", cex = 1.5),
ylab = list(label = "Order of data in the file", cex = 1.5))
print(P)
}
(tempoi <- Sys.time())
Vertemp <- MydotplotBR(df[,MyVar])
(tempof <- Sys.time()-tempoi)
I find it weird that you want a color dependent only on the x-axis when values are also used on the y-axis of other plots.
Nevertheless, here's a homemade pairs_cutoff() function doing what you want.
pairs_cutoff <- function(data, cutoff, cols = c("red", "blue"),
only.lower = F, ...){
data <- as.data.frame(data)
cns <- colnames(data)
nc <- ncol(data)
layout(matrix(seq_len(nc^2), ncol = nc))
invisible(
sapply(seq_len(nc), function(i){
sapply(seq_len(nc), function(j){
if(i == j){
plot.new()
legend("center", bty = "n", title = cns[i], cex = 1.5, text.font = 2, legend = "")
} else {
if(j < i & only.lower)
plot.new()
else{
if(is.null(cutoff))
cols <- cols[1]
plot(data[,i], data[,j], col = cols[(data[,i] < cutoff) + 1],
xlab = cns[i], ylab = cns[j], ...)
}
}
})
})
)
}
Using your suggested data :
n = 1000
dat <- tibble(
xx1 = runif(n, min = 3, max = 10),
xx2 = runif(n, min = 3, max = 10),
xx3 = runif(n, min = 3, max = 10)
)
pairs_cutoff(dat, cutoff = 5, only.lower = T)
outputs the following plot :
You can specify extra parameters to the plot function (eg. pch) directly to pairs_cutoff.
Also, if you want the full symmetric grid of plots, set only.lower = F.
I am trying to use a Gaussian Process Regression (GPR) model to predict hourly streamflow discharges in a river. I've got good results applying the caret::kernlab train () function (thanks Kuhn!).
Since the uncertainty idea is one of the main inherent ones advantages of the GPR, I would like to know if anyone could help me to access the results related to the prediction inteval of the test dataset.
I'll put an extract of the code I've been working. Since my real data are huge (and sincerely, I don't know how to put it here), I'll example with the data(airquality). The main goal in this particular example is to predict airquality$Ozone, using as predictos the lag-variables of airquality$Temperature.
rm(list = ls())
data(airquality)
airquality = na.omit(as.data.frame(airquality)); str(airquality)
library(tidyverse)
library(magrittr)
airquality$Ozone %>% plot(type = 'l')
lines(airquality$Temp, col = 2)
legend("topleft", legend = c("Ozone", "Temperature"),
col=c(1, 2), lty = 1:1, cex = 0.7, text.font = 4, inset = 0.01,
box.lty=0, lwd = 1)
attach(airquality)
df_lags <- airquality %>%
mutate(Temp_lag1 = lag(n = 1L, Temp)) %>%
na.omit()
ESM_train = data.frame(df_lags[1:81, ]) # Training Observed 75% dataset
ESM_test = data.frame(df_lags[82:nrow(df_lags), ]) # Testing Observed 25% dataset
grid_gaussprRadial = expand.grid(.sigma = c(0.001, 0.01, 0.05, 0.1, 0.5, 1, 2)) # Sigma parameters searching for GPR
# TRAIN MODEL ############################
# Tuning set
library(caret)
set.seed(111)
cvCtrl <- trainControl(
method ="repeatedcv",
repeats = 1,
number = 20,
allowParallel = TRUE,
verboseIter = TRUE,
savePredictions = "final")
# Train (aprox. 4 seconds time-simulation)
attach(ESM_train)
set.seed(111)
system.time(Model_train <- caret::train(Ozone ~ Temp + Temp_lag1,
trControl = cvCtrl,
data = ESM_train,
metric = "MAE", # Using MAE since I intend minimum values are my focus
preProcess = c("center", "scale"),
method = "gaussprRadial", # Setting RBF kernel function
tuneGrid = grid_gaussprRadial,
maxit = 1000,
linout = 1)) # Regression type
plot(Model_train)
Model_train
ESM_results_train <- Model_train$resample %>% mutate(Model = "") # K-fold Training measures
# Select the interested TRAIN data and arrange them as dataframe
Ozone_Obs_Tr = Model_train$pred$obs
Ozone_sim = Model_train$pred$pred
Resid = Ozone_Obs_Tr - Ozone_sim
train_results = data.frame(Ozone_Obs_Tr,
Ozone_sim,
Resid)
# Plot Obs x Simulated train results
library(ggplot2)
ggplot(data = train_results, aes(x = Ozone_Obs_Tr, y = Ozone_sim)) +
geom_point() +
geom_abline(intercept = 0, slope = 1, color = "black")
# TEST MODEL ############################
# From "ESM_test" dataframe, we predict ESM Ozone time series, adding it in "ESM_forecasted" dataframe
ESM_forecasted = ESM_test %>%
mutate(Ozone_Pred = predict(Model_train, newdata = ESM_test, variance.model = TRUE))
str(ESM_forecasted)
# Select the interested TEST data and arrange them as a dataframe
Ozone_Obs = ESM_forecasted$Ozone
Ozone_Pred = ESM_forecasted$Ozone_Pred
# Plot Obs x Predicted TEST results
ggplot(data = ESM_forecasted, aes(x = Ozone_Obs, y = Ozone_Pred)) +
geom_point() +
geom_abline(intercept = 0, slope = 1, color = "black")
# Model performance #####
library(hydroGOF)
gof_TR = gof(Ozone_sim, Ozone_Obs_Tr)
gof_TEST = gof(Ozone_Pred,Ozone_Obs)
Performances = data.frame(
Train = gof_TR,
Test = gof_TEST
); Performances
# Plot the TEST prediction
attach(ESM_forecasted)
plot(Ozone_Obs, type = "l", xlab = "", ylab = "", ylim = range(Ozone_Obs, Ozone_Pred))
lines(Ozone_Pred , col = "coral2", lty = 2, lwd = 2)
legend("top", legend = c("Ozone Obs Test", "Ozone Pred Test"),
col=c(1, "coral2"), lty = 1:2, cex = 0.7, text.font = 4, inset = 0.01, box.lty=0, lwd = 2)
These last lines generate the following plot:
The next, and last, step would be to extract the prediction intervals, which is based on a gaussian distribution around each prediction point, to plot it together with this last plot.
The caret::kernlab train() appliance returned better prediction than, for instance, just kernlab::gaussprRadial(), or even tgp::bgp() packages. For both of them I could find the prediction interval.
For example, to pick up the prediction intervals via tgp::bgp(), it could be done typing:
Upper_Bound <- Ozone_Pred$ZZ.q2 #Ozone_Pred - 2 * sigma^2
Lower_Bound <- Ozone_Pred$ZZ.q1 #Ozone_Pred + 2 * sigma^2
Therefore, via caret::kernlab train(), I hope the required standard deviations could be found typing something as
Model_train$...
or maybe, with
Ozone_Pred$...
Moreover, at link: https://stats.stackexchange.com/questions/414079/can-mad-median-absolute-deviation-or-mae-mean-absolute-error-be-used-to-calc,
Stephan Kolassa author explained that we could estimate the prediction intervals through MAE, or even RMSE. But I didn't understand if this is my point, since the MAE I got is just the comparison between Obs x Predicted Ozone data, in this example.
Please, this solution is very important to me! I think I am near to obtain my main results, but I don't know anymore how to try.
Thanks a lot, friends!
I don't really know how the caret framework works, but getting a prediction interval for a GP regression with a Gaussian likelihood is easy enough to do manually.
First we just need a function for the squared exponential kernel, also called the radial basis function kernel, which is what you were using. sf here is the scale factor (unused in the kernlab implementation), and ell is the length scale, called sigma in the kernlab implementation:
covSEiso <- function(x1, x2 = x1, sf = 1.0, ell = 1.0) {
sf <- sf^2
ell <- -0.5 * (1 / (ell^2))
n <- nrow(x1)
m <- nrow(x2)
d <- ncol(x1)
result <- matrix(0, nrow = n, ncol = m)
for ( j in 1:m ) {
for ( i in 1:n ) {
result[i, j] <- sf * exp(ell * sum((x1[i, ] - x2[j, ])^2))
}
}
return(result)
}
I'm not sure what your code says about which length scale to use; below I will use a length scale of 25 and scale factor of 50 (obtained via GPML's hyperparameter optimization routines). Then we use the covSEiso() function above to get the relevant covariances, and the rest is application of basic Gaussian identities. I would refer you to Chapter 2 of Rasmussen and Williams (2006) (graciously provided for free online).
data(airquality)
library(tidyverse)
library(magrittr)
df_lags <- airquality %>%
mutate(Temp_lag1 = lag(n = 1L, Temp)) %>%
na.omit()
ESM_train <- data.frame(df_lags[1:81, ]) # Training Data 75% dataset
ESM_test <- data.frame(df_lags[82:nrow(df_lags), ]) # Testing Data 25% dataset
## For convenience I'll define separately the training and test inputs
X <- ESM_train[ , c("Temp", "Temp_lag1")]
Xstar <- ESM_test[ , c("Temp", "Temp_lag1")]
## Get the kernel manually
K <- covSEiso(X, ell = 25, sf = 50)
## We also need covariance between the test cases
Kstar <- covSEiso(Xstar, X, ell = 25, sf = 50)
Ktest <- covSEiso(Xstar, ell = 25, sf = 50)
## Now the 95% credible region for the posterior is
predictive_mean <- Kstar %*% solve(K + diag(nrow(K))) %*% ESM_train$Ozone
predictive_var <- Ktest - (Kstar %*% solve(K + diag(nrow(K))) %*% t(Kstar))
## Then for the prediction interval we only need to add the observation noise
z <- sqrt(diag(predictive_var)) + 25
interval_high <- predictive_mean + 2 * z
interval_low <- predictive_mean - 2 * z
Then we can check out the prediction intervals
This all is pretty easy to do via my gplmr package (available on GitHub) which can call GPML from R if you have Octave installed:
data(airquality)
library(tidyverse)
library(magrittr)
library(gpmlr)
df_lags <- airquality %>%
mutate(Temp_lag1 = lag(n = 1L, Temp)) %>%
na.omit()
ESM_train <- data.frame(df_lags[1:81, ]) # Training Data 75% dataset
ESM_test <- data.frame(df_lags[82:nrow(df_lags), ]) # Testing Data 25% dataset
X <- as.matrix(ESM_train[ , c("Temp", "Temp_lag1")])
y <- ESM_train$Ozone
Xs <- as.matrix(ESM_test[ , c("Temp", "Temp_lag1")])
ys <- ESM_test$Ozone
hyp0 <- list(mean = numeric(), cov = c(0, 0), lik = 0)
hyp <- set_hyperparameters(hyp0, "infExact", "meanZero", "covSEiso","likGauss",
X, y)
gp_res <- gp(hyp, "infExact", "meanZero", "covSEiso", "likGauss", X, y, Xs, ys)
predictive_mean <- gp_res$YMU
interval_high <- gp_res$YMU + 2 * sqrt(gp_res$YS2)
interval_low <- gp_res$YMU - 2 * sqrt(gp_res$YS2)
Then just plot the predictions, as above:
plot(NULL, xlab = "", ylab = "", xaxt = "n", yaxt = "n",
xlim = range(ESM_test$Temp), ylim = range(c(interval_high, interval_low)))
axis(1, tick = FALSE, line = -0.75)
axis(2, tick = FALSE, line = -0.75)
mtext("Temp", 1, 1.5)
mtext("Ozone", 2, 1.5)
idx <- order(ESM_test$Temp)
polygon(c(ESM_test$Temp[idx], rev(ESM_test$Temp[idx])),
c(interval_high[idx], rev(interval_low[idx])),
border = NA, col = "#80808080")
lines(ESM_test$Temp[idx], predictive_mean[idx])
points(ESM_test$Temp, ESM_test$Ozone, pch = 19)
plot(NULL, xlab = "", ylab = "", xaxt = "n", yaxt = "n",
xlim = range(ESM_test$Temp_lag1), ylim = range(c(interval_high, interval_low)))
axis(1, tick = FALSE, line = -0.75)
axis(2, tick = FALSE, line = -0.75)
mtext("Temp_lag1", 1, 1.5)
mtext("Ozone", 2, 1.5)
idx <- order(ESM_test$Temp_lag1)
polygon(c(ESM_test$Temp_lag1[idx], rev(ESM_test$Temp_lag1[idx])),
c(interval_high[idx], rev(interval_low[idx])),
border = NA, col = "#80808080")
lines(ESM_test$Temp_lag1[idx], predictive_mean[idx])
points(ESM_test$Temp_lag1, ESM_test$Ozone, pch = 19)
I would like to add a gradient of colours following the fitted values (e.g. higher fitted values darker colours, lower fitted values lighter colours) in my three-dimensional dependence plots.
I have used the example presented in dismo package:
library(dismo)
data(Anguilla_train)
angaus.tc5.lr01 <- gbm.step(data=Anguilla_train, gbm.x = 3:13, gbm.y = 2,
family = "bernoulli", tree.complexity = 5, learning.rate = 0.01,
bag.fraction = 0.5)
# Find interactions in the gbm model:
find.int <- gbm.interactions( angaus.tc5.lr01)
find.int$interactions
find.int$rank.list
I have only managed to add the same colour to the whole plot:
gbm.perspec( angaus.tc5.lr01, 7, 1,
x.label = "USRainDays",
y.label = "SegSumT",
z.label = "Fitted values",
z.range=c(0,0.435),
col="blue")
Or to add a gradient colour but not following the fitted values:
gbm.perspec( angaus.tc5.lr01, 7, 1,
x.label = "USRainDays",
y.label = "SegSumT",
z.label = "Fitted values",
col=heat.colors(50),
z.range=c(0,0.435))
I also checked the code of function gbm.perspec, and If I understood correctly the fitted values are call inside the formula as "prediction", and later on are part of the "pred.matrix" that is passed to the final plotting: persp(x = x.var, y = y.var, z = pred.matrix...), but I have no managed to access them from the gbm.perspec formula. I tried to modified the gbm.perpec function by adding "col=heat.colors(100)[round(pred.matrix*100, 0)]" into the persp() inside the function, but it does not do what I am looking for:
persp(x = x.var, y = y.var, z = pred.matrix, zlim = z.range,
xlab = x.label, ylab = y.label, zlab = z.label,
theta = theta, phi = phi, r = sqrt(10), d = 3,
ticktype = ticktype,
col=heat.colors(100)[round(pred.matrix*100, 0)],
mgp = c(4, 1, 0), ...)
I believe the solution might come from modifying the gbm.perpec function, do you know how?
Thank you for your time!
Modifying the gbm.perspec function is certainly an option, although if you use the predicted values from the gbm model and plot them onto a 3D scatterplot from another package you should be able to achieve it as well.
Here's an option using the plot3Drgl package, original code was provided by #Fabrice.
library(dismo); library(plot3Drgl); library(devEMF)
data(Anguilla_train)
angaus.tc5.lr01 <- gbm.step(data=Anguilla_train, gbm.x = 3:13, gbm.y = 2,
family = "bernoulli", tree.complexity = 5, learning.rate = 0.01,
bag.fraction = 0.5)
# Find interactions in the gbm model:
find.int <- gbm.interactions( angaus.tc5.lr01)
find.int$interactions
find.int$rank.list
d<-plot(angaus.tc5.lr01,c(1,7),return.grid=T)
x <- d$SegSumT
y <- d$USRainDays
z <- d$y
grid.lines = 30
elevation.site = loess(z ~ x*y, data=d, span=1, normalize = FALSE)
x.pred <- seq(min(x), max(x), length.out = grid.lines) # x grid
y.pred <- seq(min(y), max(y), length.out = grid.lines) # y grid
xy <- expand.grid( x = x.pred, y = y.pred) # final grid combined
z.site=matrix(predict(elevation.site, newdata = xy), nrow = grid.lines, ncol = grid.lines) # predicedt matrix
scatter3D(x, y, z, theta = 160, phi = 35, # x y z coords and angle of plot
clab = c(""), # Needs moving - label legend
colkey = list(side = 4, length = 0.65,
adj.clab = 0.15, dist = -0.15, cex.clab = 0.6, cex.axis = 0.6), # change the location and length of legend, change position of label and legend
clim = c(-4,0.1),
bty = "b", # type of box
col = ramp.col(col = c("grey", "blue"), 200),
pch = 19, cex = 0.55, # shape and size of points
xlab = "SegSumT",
xlim=c(10,20),ylim=c(0,3.5), zlim=c(-4,0.1), d= 2,
ylab = "USRaindays",
zlab= "Fitted values", #axes labels
cex.lab = 0.8, font.lab = 1, cex.axis = 0.6, font.axis= 1, # size and font of axes and ticks
ticktype = "detailed", nticks = 5, # ticks and numer of ticks
#type = "h", # vertical lines
surf = list(x = x.pred, y = y.pred, z = z.site,
facets = NA, CI=NULL))
enter image description here
By tweaking with grid.lines and reversing the x axis you should be able to produce exactly what you want.
By incorporating some of the code found here into the gbm.perspec() source code you can create the desired effect.
First run
# Color palette (100 colors)
col.pal<-colorRampPalette(c("blue", "red"))
colors<-col.pal(100)
Then, add z.facet.center to gbm.perspec() source code after else and change the z in the code to pred.matrixas follows,
# and finally plot the result
#
if (!perspective) {
image(x = x.var, y = y.var, z = pred.matrix, zlim = z.range)
} else {
z.facet.center <- (pred.matrix[-1, -1] + pred.matrix[-1, -ncol(pred.matrix)] +
pred.matrix[-nrow(pred.matrix), -1] + pred.matrix[-nrow(pred.matrix), -ncol(pred.matrix)])/4
# Range of the facet center on a 100-scale (number of colors)
z.facet.range<-cut(z.facet.center, 100)
persp(x=x.var, y=y.var, z=pred.matrix, zlim= z.range, # input vars
xlab = x.label, ylab = y.label, zlab = z.label, # labels
theta=theta, phi=phi, r = sqrt(10), d = 3,
col=colors[z.facet.range],# viewing pars
ticktype = ticktype, mgp = c(4,1,0), ...) #
which will give you a plot like this (please note, this is not plotted using the sample dataset which is why the interaction effect is different than the plot in the question).
Alternatively, you can create a new function. The following example modifies gbm.perspec() to give a white-to-red gradient. Simply run the code in R, then change gbm.perspec() to gbm.perspec2()
# interaction function
# Color palette (100 colors)
col.pal<-colorRampPalette(c("white", "pink", "red"))
colors<-col.pal(100)
gbm.perspec2 <- function(gbm.object,
x = 1, # the first variable to be plotted
y = 2, # the second variable to be plotted
pred.means = NULL, # allows specification of values for other variables
x.label = NULL, # allows manual specification of the x label
x.range = NULL, # manual range specification for the x variable
y.label = NULL, # and y la seminar committeebel
z.label = "fitted value", #default z label
y.range = NULL, # and the y
z.range = NULL, # allows control of the vertical axis
leg.coords = NULL, #can specify coords (x, y) for legend
ticktype = "detailed",# specifiy detailed types - otherwise "simple"
theta = 55, # rotation
phi=40, # and elevation
smooth = "none", # controls smoothing of the predicted surface
mask = FALSE, # controls masking using a sample intensity model
perspective = TRUE, # controls whether a contour or perspective plot is drawn
...) # allows the passing of additional arguments to plotting routine
# useful options include shade, ltheta, lphi for controlling illumination
# and cex for controlling text size - cex.axis and cex.lab have no effect
{
if (! requireNamespace('gbm') ) { stop('you need to install the gbm package to use this function') }
requireNamespace('splines')
#get the boosting model details
gbm.call <- gbm.object$gbm.call
gbm.x <- gbm.call$gbm.x
n.preds <- length(gbm.x)
gbm.y <- gbm.call$gbm.y
pred.names <- gbm.call$predictor.names
family = gbm.call$family
# and now set up range variables for the x and y preds
have.factor <- FALSE
x.name <- gbm.call$predictor.names[x]
if (is.null(x.label)) {
x.label <- gbm.call$predictor.names[x]
}
y.name <- gbm.call$predictor.names[y]
if (is.null(y.label)) {
y.label <- gbm.call$predictor.names[y]
}
data <- gbm.call$dataframe[ , gbm.x, drop=FALSE]
n.trees <- gbm.call$best.trees
# if marginal variable is a vector then create intervals along the range
if (is.vector(data[,x])) {
if (is.null(x.range)) {
x.var <- seq(min(data[,x],na.rm=T),max(data[,x],na.rm=T),length = 50)
} else {
x.var <- seq(x.range[1],x.range[2],length = 50)
}
} else {
x.var <- names(table(data[,x]))
have.factor <- TRUE
}
if (is.vector(data[,y])) {
if (is.null(y.range)) {
y.var <- seq(min(data[,y],na.rm=T),max(data[,y],na.rm=T),length = 50)
} else {y.var <- seq(y.range[1],y.range[2],length = 50)}
} else {
y.var <- names(table(data[,y]))
if (have.factor) { #check that we don't already have a factor
stop("at least one marginal predictor must be a vector!")
} else {have.factor <- TRUE}
}
pred.frame <- expand.grid(list(x.var,y.var))
names(pred.frame) <- c(x.name,y.name)
pred.rows <- nrow(pred.frame)
#make sure that the factor variable comes first
if (have.factor) {
if (is.factor(pred.frame[,2])) { # swap them about
pred.frame <- pred.frame[,c(2,1)]
x.var <- y.var
}
}
j <- 3
# cycle through the predictors
# if a non-target variable find the mean
for (i in 1:n.preds) {
if (i != x & i != y) {
if (is.vector(data[,i])) {
m <- match(pred.names[i],names(pred.means))
if (is.na(m)) {
pred.frame[,j] <- mean(data[,i],na.rm=T)
} else pred.frame[,j] <- pred.means[m]
}
if (is.factor(data[,i])) {
m <- match(pred.names[i],names(pred.means))
temp.table <- table(data[,i])
if (is.na(m)) {
pred.frame[,j] <- rep(names(temp.table)[2],pred.rows)
} else {
pred.frame[,j] <- pred.means[m]
}
pred.frame[,j] <- factor(pred.frame[,j],levels=names(temp.table))
}
names(pred.frame)[j] <- pred.names[i]
j <- j + 1
}
}
#
# form the prediction
#
#assign("pred.frame", pred.frame, pos=1)
prediction <- gbm::predict.gbm(gbm.object,pred.frame,n.trees = n.trees, type="response")
#assign("prediction", prediction, pos=1, immediate =T)
# model smooth if required
if (smooth == "model") {
pred.glm <- glm(prediction ~ ns(pred.frame[,1], df = 8) * ns(pred.frame[,2], df = 8), data=pred.frame,family=poisson)
prediction <- fitted(pred.glm)
}
# report the maximum value and set up realistic ranges for z
max.pred <- max(prediction)
message("maximum value = ",round(max.pred,2),"\n")
if (is.null(z.range)) {
if (family == "bernoulli") {
z.range <- c(0,1)
} else if (family == "poisson") {
z.range <- c(0,max.pred * 1.1)
} else {
z.min <- min(data[,y],na.rm=T)
z.max <- max(data[,y],na.rm=T)
z.delta <- z.max - z.min
z.range <- c(z.min - (1.1 * z.delta), z.max + (1.1 * z.delta))
}
}
# now process assuming both x and y are vectors
if (have.factor == FALSE) {
# form the matrix
pred.matrix <- matrix(prediction,ncol=50,nrow=50)
# kernel smooth if required
if (smooth == "average") { #apply a 3 x 3 smoothing average
pred.matrix.smooth <- pred.matrix
for (i in 2:49) {
for (j in 2:49) {
pred.matrix.smooth[i,j] <- mean(pred.matrix[c((i-1):(i+1)),c((j-1):(j+1))])
}
}
pred.matrix <- pred.matrix.smooth
}
# mask out values inside hyper-rectangle but outside of sample space
if (mask) {
mask.trees <- gbm.object$gbm.call$best.trees
point.prob <- gbm::predict.gbm(gbm.object[[1]],pred.frame, n.trees = mask.trees, type="response")
point.prob <- matrix(point.prob,ncol=50,nrow=50)
pred.matrix[point.prob < 0.5] <- 0.0
}
#
# and finally plot the result
#
if (!perspective) {
image(x = x.var, y = y.var, z = pred.matrix, zlim = z.range)
} else {
z.facet.center <- (pred.matrix[-1, -1] + pred.matrix[-1, -ncol(pred.matrix)] +
pred.matrix[-nrow(pred.matrix), -1] + pred.matrix[-nrow(pred.matrix), -ncol(pred.matrix)])/4
# Range of the facet center on a 100-scale (number of colors)
z.facet.range<-cut(z.facet.center, 100)
persp(x=x.var, y=y.var, z=pred.matrix, zlim= z.range, # input vars
xlab = x.label, ylab = y.label, zlab = z.label, # labels
theta=theta, phi=phi, r = sqrt(10), d = 3,
col=colors[z.facet.range],# viewing pars
ticktype = ticktype, mgp = c(4,1,0), ...) #
}
}
if (have.factor) {
# we need to plot values of y for each x
factor.list <- names(table(pred.frame[,1]))
n <- 1
#add this bit so z.range still works as expected:
if (is.null(z.range)) {
vert.limits <- c(0, max.pred * 1.1)
} else {
vert.limits <- z.range
}
plot(pred.frame[pred.frame[,1]==factor.list[1],2],
prediction[pred.frame[,1]==factor.list[1]],
type = 'l',
#ylim = c(0, max.pred * 1.1),
ylim = vert.limits,
xlab = y.label,
ylab = z.label, ...)
for (i in 2:length(factor.list)) {
#factor.level in factor.list) {
factor.level <- factor.list[i]
lines(pred.frame[pred.frame[,1]==factor.level,2],
prediction[pred.frame[,1]==factor.level], lty = i)
}
# now draw a legend
if(is.null(leg.coords)){
x.max <- max(pred.frame[,2])
x.min <- min(pred.frame[,2])
x.range <- x.max - x.min
x.pos <- c(x.min + (0.02 * x.range),x.min + (0.3 * x.range))
y.max <- max(prediction)
y.min <- min(prediction)
y.range <- y.max - y.min
y.pos <- c(y.min + (0.8 * y.range),y.min + (0.95 * y.range))
legend(x = x.pos, y = y.pos, factor.list, lty = c(1:length(factor.list)), bty = "n")
} else {
legend(x = leg.coords[1], y = leg.coords[2], factor.list, lty = c(1:length(factor.list)), bty = "n", ncol = 2)
}
}
}