Plotting axes in R - r

I am supposed to plot the following function:
h <- function(x) 0.08-0.06*(1-exp((-x)/(1.5)))/((x)/(1.5))-0.3*((1-exp((-x)/(1.5)))/((x)/(1.5))-exp(-((x)/(1.5)))+0.6*((1-exp((-x)/(0.5)))/((x)/(0.5))-exp(-((x)/(0.5)))))
So I did:
plot(-1:24, h(-1:24), type="l")
and it would be for x-axes. But I do not know how to change it for y.
For x I want to draw it from -1 to 24 and for y from -0.5 to 0.2.
Can anybody help?

An issue with your function is that it is undefined at 0, so you get a single point at x == -1 followed by a gap until x == 1. You'll get a better plot with more points, e.g.
x <- seq(-1, 24, len=200)
plot(x, h(x), type = "l")
(which never evaluates it at exactly zero, so the gap doesn't appear).
If you still want to change the axis limits, use
x <- seq(-1, 24, len=200)
plot(x, h(x), type = "l", ylim = c(-0.5, 2))

With ggplot2 you can do:
library(ggplot2)
data = data.frame(x = -1:24)
ggplot(data, aes(x=x)) + stat_function(fun=h) + ylim(-0.5,2)
Or
data = data.frame(x = -1:24, y = h(-1:24))
ggplot(data, aes(x=x, y=y)) + geom_line() + ylim(-0.5,2)
But a solution with plot is probably easier as its a very simple thing, ggplot is kinda overkill i guess.

Related

GGplot second y axis without the transformation of y axis

Does any one know how do you apply this
set.seed(101)
x <- 1:10
y <- rnorm(10)
## second data set on a very different scale
z <- runif(10, min=1000, max=10000)
par(mar = c(5, 4, 4, 4) + 0.3) # Leave space for z axis
plot(x, y) # first plot
par(new = TRUE)
plot(x, z, type = "l", axes = FALSE, bty = "n", xlab = "", ylab = "")
axis(side=4, at = pretty(range(z)))
mtext("z", side=4, line=3)
but using ggplot.
In ggplot you can only create sec.axis() or dup.axis() using a transformation of y axis. What about a whole new independent y axis which will be applied only for z variable and the simple y axis to be applied for the y variable.
ggplot2::sec_axis provides only one mechanism for providing a second axis, and it took a lot of convincing to get that into the codebase. You are responsible for coming up with the transformation. This transform must be linear in some way, so if either axis needs to be non-linear (e.g., exponential, logarithmic, etc), then your expert math skills will be put to the test.
If you can use scales, then this process becomes trivial:
dat <- data.frame(x, y, z)
ggplot(dat, aes(x, y)) +
geom_point() +
geom_line(
aes(y = zmod),
data = ~ transform(., zmod = scales::rescale(z, range(y), range(z)))
) +
scale_y_continuous(
sec.axis = sec_axis(~ scales::rescale(., range(dat$z), range(dat$y)),
breaks = c(2000,4000,6000,8000))
)
Unless I've missed something (I just checked ggplot2-3.3.5's NEWS.md file), this has not changed.

how to overlay boxplot across a scatterplot?

fake data
set.seed( 123)
x<-rnorm(1000, mean=60,sd=20)
y <- exp(-10 + .95*log(x^3)) + rnorm(1000,mean=1,sd=1)
df <- data.frame(x,y)
cls.x <- quantile(df$x, seq(.1, .9, by=.1))
df$x.class <- findInterval(df$x, cls.x)
df$x.class <- as.factor(df$x.class)
head(df)
Neither the following work
plot(df$x,df$y,col=3)
par(new=T)
boxplot(y~x.class, data=df,xlab="",ylab="",xaxt="n")
nor this
boxplot(y~x.class, data=df,xlab="",ylab="",xaxt="n")
points(df$x,df$y,col=3)
Using ggplot, the closest I get is using something like
library(ggplot2)
ggplot(df,aes(x.class,y))+geom_boxplot() + geom_point()
Unfortunately, It does not show the real variability in the-axis.
I tried with the jitter option, but I was not able to force the plot to use the real variability of the X-variable
Any suggestion would be very much appreciated.
Ps: I am aware of the bplot.xy() function in Rlab, however, that function does not allow me to change colours of the boxplot, or plot the dots first.
library(Rlab)
bplot.xy( x,y, N=10)
points( x,y, pch=".", col=3, cex=3)
Your df$x varies from 3 to 124, whereas your x-axis is from 1 to 10. In base graphics, you can do this:
plot(jitter(as.integer(df$x.class)), df$y, col=3, type="p", xlab = "", ylab = "", xaxt = "n")
boxplot(y~x.class, data=df,xlab="",ylab="",xaxt="n", add = TRUE)
I added jitter to help break out the distribution. You might also try pch=16 to make the dots solid, and perhaps use transparency (e.g., col="#aaffaa22" for the dots).
Is the following what you want?
library(ggplot2)
ggplot(df, aes(x, y, fill = x.class)) +
geom_point(alpha = 0.10) +
geom_boxplot(alpha = 0.50)

How to plot a surface in rgl plot3d

So I have this code that produces the exact surface
f = function(x, y){
z = ((x^2)+(3*y^2))*exp(-(x^2)-(y^2))
}
plot3d(f, col = colorRampPalette(c("blue", "white")),
xlab = "X", ylab = "Y", zlab = "Z",
xlim = c(-3, 3), ylim = c(-3, 3),
aspect = c(1, 1, 0.5))
Giving the following plot:
Now I have some code that does a random walk metropolis algorithm to reproduce the above image. I think it works as if I do another plot of these calculated values I get the next image with 500 points. Here is the code
open3d()
plot3d(x0, y0, f(x0, y0), type = "p")
Which gives the following plot:
I know it's hard looking at this still image but being able to rotate the sampling is working.
Now here is my question: How can I use plot3d() so that I can have a surface that connects all these points and gives a more jagged representation of the exact plot? Or how can I have each point in the z axis as a bar from the xy plane? I just want something more 3 dimensional than points and I can't find how to do this.
Thanks for your help
You can do this by triangulating the surface. You don't give us your actual data, but I can create some similar data using
f = function(x, y){
z = ((x^2)+(3*y^2))*exp(-(x^2)-(y^2))
}
x <- runif(500, -3, 3)
y <- runif(500, -3, 3)
z <- f(x, y)
Then the plotting is done using the method in ?persp3d.deldir:
library(deldir)
library(rgl)
col <- colorRampPalette(c("blue", "white"))(20)[1 + round(19*(z - min(z))/diff(range(z)))]
dxyz <- deldir::deldir(x, y, z = z, suppressMsge = TRUE)
persp3d(dxyz, col = col, front = "lines", back = "lines")
This might need some cosmetic fixes, e.g.
aspect3d(2, 2, 1)
After some rotation, this gives me the following plot:
I'm not sure to understand what you want. If my understanding is correct, here is a solution. Define a parametric representation of your surface:
fx <- function(u,v) u
fy <- function(u,v) v
fz <- function(u,v){
((u^2)+(3*v^2))*exp(-(u^2)-(v^2))
}
Let's say you have these points:
x0 <- seq(-3, 3, length.out = 20)
y0 <- seq(-3, 3, length.out = 20)
Then you can use the function parametric3d of the misc3d package, with the option fill=FALSE to get a wireframe:
library(misc3d)
parametric3d(fx, fy, fz, u=x0, v=y0,
color="blue", fill = FALSE)
Is it what you want?
To get some vertical bars, use the function segments3d of rgl:
i <- 8
bar <- rbind(c(x0[i],y0[i],0),c(x0[i],y0[i],f(x0[i],y0[i])))
segments3d(bar, color="red")
Here is a plot with only 50 points using my original code.
When I then apply what was said by Stéphane Laurent I then get this plot which feels too accurate when given the actual points I have
Perhaps you need to explain to me what is actually happening in the function parametric3d

How to plot multiple columns at the same time? [duplicate]

I would like to plot y1 and y2 in the same plot.
x <- seq(-2, 2, 0.05)
y1 <- pnorm(x)
y2 <- pnorm(x, 1, 1)
plot(x, y1, type = "l", col = "red")
plot(x, y2, type = "l", col = "green")
But when I do it like this, they are not plotted in the same plot together.
In Matlab one can do hold on, but does anyone know how to do this in R?
lines() or points() will add to the existing graph, but will not create a new window. So you'd need to do
plot(x,y1,type="l",col="red")
lines(x,y2,col="green")
You can also use par and plot on the same graph but different axis. Something as follows:
plot( x, y1, type="l", col="red" )
par(new=TRUE)
plot( x, y2, type="l", col="green" )
If you read in detail about par in R, you will be able to generate really interesting graphs. Another book to look at is Paul Murrel's R Graphics.
When constructing multilayer plots one should consider ggplot package. The idea is to create a graphical object with basic aesthetics and enhance it incrementally.
ggplot style requires data to be packed in data.frame.
# Data generation
x <- seq(-2, 2, 0.05)
y1 <- pnorm(x)
y2 <- pnorm(x,1,1)
df <- data.frame(x,y1,y2)
Basic solution:
require(ggplot2)
ggplot(df, aes(x)) + # basic graphical object
geom_line(aes(y=y1), colour="red") + # first layer
geom_line(aes(y=y2), colour="green") # second layer
Here + operator is used to add extra layers to basic object.
With ggplot you have access to graphical object on every stage of plotting. Say, usual step-by-step setup can look like this:
g <- ggplot(df, aes(x))
g <- g + geom_line(aes(y=y1), colour="red")
g <- g + geom_line(aes(y=y2), colour="green")
g
g produces the plot, and you can see it at every stage (well, after creation of at least one layer). Further enchantments of the plot are also made with created object. For example, we can add labels for axises:
g <- g + ylab("Y") + xlab("X")
g
Final g looks like:
UPDATE (2013-11-08):
As pointed out in comments, ggplot's philosophy suggests using data in long format.
You can refer to this answer in order to see the corresponding code.
I think that the answer you are looking for is:
plot(first thing to plot)
plot(second thing to plot,add=TRUE)
Use the matplot function:
matplot(x, cbind(y1,y2),type="l",col=c("red","green"),lty=c(1,1))
use this if y1 and y2 are evaluated at the same x points. It scales the Y-axis to fit whichever is bigger (y1 or y2), unlike some of the other answers here that will clip y2 if it gets bigger than y1 (ggplot solutions mostly are okay with this).
Alternatively, and if the two lines don't have the same x-coordinates, set the axis limits on the first plot and add:
x1 <- seq(-2, 2, 0.05)
x2 <- seq(-3, 3, 0.05)
y1 <- pnorm(x1)
y2 <- pnorm(x2,1,1)
plot(x1,y1,ylim=range(c(y1,y2)),xlim=range(c(x1,x2)), type="l",col="red")
lines(x2,y2,col="green")
Am astonished this Q is 4 years old and nobody has mentioned matplot or x/ylim...
tl;dr: You want to use curve (with add=TRUE) or lines.
I disagree with par(new=TRUE) because that will double-print tick-marks and axis labels. Eg
The output of plot(sin); par(new=T); plot( function(x) x**2 ).
Look how messed up the vertical axis labels are! Since the ranges are different you would need to set ylim=c(lowest point between the two functions, highest point between the two functions), which is less easy than what I'm about to show you---and way less easy if you want to add not just two curves, but many.
What always confused me about plotting is the difference between curve and lines. (If you can't remember that these are the names of the two important plotting commands, just sing it.)
Here's the big difference between curve and lines.
curve will plot a function, like curve(sin). lines plots points with x and y values, like: lines( x=0:10, y=sin(0:10) ).
And here's a minor difference: curve needs to be called with add=TRUE for what you're trying to do, while lines already assumes you're adding to an existing plot.
Here's the result of calling plot(0:2); curve(sin).
Behind the scenes, check out methods(plot). And check body( plot.function )[[5]]. When you call plot(sin) R figures out that sin is a function (not y values) and uses the plot.function method, which ends up calling curve. So curve is the tool meant to handle functions.
if you want to split the plot into two columns (2 plots next to each other), you can do it like this:
par(mfrow=c(1,2))
plot(x)
plot(y)
Reference Link
As described by #redmode, you may plot the two lines in the same graphical device using ggplot. In that answer the data were in a 'wide' format. However, when using ggplot it is generally most convenient to keep the data in a data frame in a 'long' format. Then, by using different 'grouping variables' in the aesthetics arguments, properties of the line, such as linetype or colour, will vary according to the grouping variable, and corresponding legends will appear.
In this case, we can use the colour aessthetics, which matches colour of the lines to different levels of a variable in the data set (here: y1 vs y2). But first we need to melt the data from wide to long format, using e.g. the function 'melt' from reshape2 package. Other methods to reshape the data are described here: Reshaping data.frame from wide to long format.
library(ggplot2)
library(reshape2)
# original data in a 'wide' format
x <- seq(-2, 2, 0.05)
y1 <- pnorm(x)
y2 <- pnorm(x, 1, 1)
df <- data.frame(x, y1, y2)
# melt the data to a long format
df2 <- melt(data = df, id.vars = "x")
# plot, using the aesthetics argument 'colour'
ggplot(data = df2, aes(x = x, y = value, colour = variable)) + geom_line()
If you are using base graphics (i.e. not lattice/ grid graphics), then you can mimic MATLAB's hold on feature by using the points/lines/polygons functions to add additional details to your plots without starting a new plot. In the case of a multiplot layout, you can use par(mfg=...) to pick which plot you add things to.
You can use points for the overplot, that is.
plot(x1, y1,col='red')
points(x2,y2,col='blue')
Idiomatic Matlab plot(x1,y1,x2,y2) can be translated in R with ggplot2 for example in this way:
x1 <- seq(1,10,.2)
df1 <- data.frame(x=x1,y=log(x1),type="Log")
x2 <- seq(1,10)
df2 <- data.frame(x=x2,y=cumsum(1/x2),type="Harmonic")
df <- rbind(df1,df2)
library(ggplot2)
ggplot(df)+geom_line(aes(x,y,colour=type))
Inspired by Tingting Zhao's Dual line plots with different range of x-axis Using ggplot2.
Rather than keeping the values to be plotted in an array, store them in a matrix. By default the entire matrix will be treated as one data set. However if you add the same number of modifiers to the plot, e.g. the col(), as you have rows in the matrix, R will figure out that each row should be treated independently. For example:
x = matrix( c(21,50,80,41), nrow=2 )
y = matrix( c(1,2,1,2), nrow=2 )
plot(x, y, col("red","blue")
This should work unless your data sets are of differing sizes.
You could use the ggplotly() function from the plotly package to turn any of the gggplot2 examples here into an interactive plot, but I think this sort of plot is better without ggplot2:
# call Plotly and enter username and key
library(plotly)
x <- seq(-2, 2, 0.05)
y1 <- pnorm(x)
y2 <- pnorm(x, 1, 1)
plot_ly(x = x) %>%
add_lines(y = y1, color = I("red"), name = "Red") %>%
add_lines(y = y2, color = I("green"), name = "Green")
You can also create your plot using ggvis:
library(ggvis)
x <- seq(-2, 2, 0.05)
y1 <- pnorm(x)
y2 <- pnorm(x,1,1)
df <- data.frame(x, y1, y2)
df %>%
ggvis(~x, ~y1, stroke := 'red') %>%
layer_paths() %>%
layer_paths(data = df, x = ~x, y = ~y2, stroke := 'blue')
This will create the following plot:
Using plotly (adding solution from plotly with primary and secondary y axis- It seems to be missing):
library(plotly)
x <- seq(-2, 2, 0.05)
y1 <- pnorm(x)
y2 <- pnorm(x, 1, 1)
df=cbind.data.frame(x,y1,y2)
plot_ly(df) %>%
add_trace(x=~x,y=~y1,name = 'Line 1',type = 'scatter',mode = 'lines+markers',connectgaps = TRUE) %>%
add_trace(x=~x,y=~y2,name = 'Line 2',type = 'scatter',mode = 'lines+markers',connectgaps = TRUE,yaxis = "y2") %>%
layout(title = 'Title',
xaxis = list(title = "X-axis title"),
yaxis2 = list(side = 'right', overlaying = "y", title = 'secondary y axis', showgrid = FALSE, zeroline = FALSE))
Screenshot from working demo:
we can also use lattice library
library(lattice)
x <- seq(-2,2,0.05)
y1 <- pnorm(x)
y2 <- pnorm(x,1,1)
xyplot(y1 + y2 ~ x, ylab = "y1 and y2", type = "l", auto.key = list(points = FALSE,lines = TRUE))
For specific colors
xyplot(y1 + y2 ~ x,ylab = "y1 and y2", type = "l", auto.key = list(points = F,lines = T), par.settings = list(superpose.line = list(col = c("red","green"))))
Use curve for mathematical functions.
And use add=TRUE to use the same plot and axis.
curve( log2 , to=5 , col="black", ylab="log's(.)")
curve( log , add=TRUE , col="red" )
curve( log10, add=TRUE , col="blue" )
abline( h=0 )

Plotting two Poisson processes on one plot

I have two Poisson processes:
n <- 100
x <- seq(0, 10, length = 1000)
y1 <- cumsum(rpois(1000, 1 / n))
y2 <- -cumsum(rpois(1000, 1 / n))
I would like to plot them in one plot and expect that y1 lies above x-axis and y2 lies below x-axis. I tried the following code:
plot(x, y1)
par(new = TRUE)
plot(x, y2, col = "red",
axes = FALSE,
xlab = '', ylab = '',
xlim = c(0, 10), ylim = c(min(y2), max(y1)))
but it did not work. Can someone please tell me how to fix this? (I am working with R for my code)
Many thanks in advance
How about
plot(x,y1, ylim=range(y1,y2), type="l")
lines(x, y2, col="red")
I would suggest trying to avoid multiple calls to plot with par(new=TRUE). That is usually very messy. Here we use lines() to add to an existing plot. The only catch is that the x and y limits won't change based on the new data, so we use ylim in the first plot() call to set a range appropriate for all the data.
Or if you don't want to worry about limits (like MrFlick mentioned) or the number of lines, you could also tide up your data and using melt and ggplot
df <- data.frame(x, y1, y2)
library(reshape2)
library(ggplot2)
mdf <- melt(df, "x")
ggplot(mdf, aes(x, value, color = variable)) +
geom_line()

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