pyqtgraph: how to add a large number of plots - pyqtgraph

I want to add about 200 plots into the graphicsLayoutWidget, when I click one button.But now the gui freezes for about 10 seconds.
How can I avoid this.

This is a flaw in pyqtgraph.
It looks like the majority of initialization time is taken up creating context menus. PlotItem.__init__ and ViewBox.__init__ both have "enableMenu" arguments, but setting these to False simply stops the menu from appearing and does not stop them being created.
So the easiest way to fix this is to simply avoid creating the menus at all, and a better way would be to defer the menu creation until the user right-clicks on the plot. You can try the former solution by checking out this code: https://github.com/lcampagn/pyqtgraph/tree/deferred_menu
Under that code, the following example runs much faster:
import pyqtgraph as pg
w = pg.GraphicsWindow()
for i in range(20):
for j in range(20):
w.addPlot(enableMenu=False)
w.nextRow()
The latter solution would require more extensive changes. Further performance improvements could be made by avoiding displaying AxisItems

Related

How to prevent a plot from the past repainting?

Is there a way to prevent a plot that has already appeared from erasing itself shortly after? I'm using pinescript on TradingView and an indicator sometimes does this. I'm aware it is due to security() and lookahead_on, and that repainting in the code should be avoided entirely, but I'd like to experiment with just making sure the plot itself is permanent when it appears, irrespective as to whether the code tells it to erase itself.
Thanks for any help
It's hard to tell without seeing your code.
For security() you can use the following function:
f_secureSecurity(_symbol, _res, _src) => security(_symbol, _res, _src[1], lookahead = barmerge.lookahead_on)
For other cases, you can use the barstate.isconfirmed built-in variable together with your other conditions that feeds the plot(). barstate.isconfirmed will be true with the last update of the bar. So, in that caase, the price action would be confirmed.

How to add a progress bar to a package function in r

I am running a moving window function from the package landscapemetrics. This seems to take some time as the raster is quite big. It would be really helpful to have a progress bar or something similar. How can I code something like this without having a for loop or a self-coded function to begin with? I don't know how to provide an example raster, but here is my code:
my.raster <- raster('forest2_nonforest1_min_extent.tif')
#specify window size
moving_window <- matrix(1,nrow=5,ncol=5)
#moving window analysis
tt <- window_lsm(my.raster,
window = moving_window,
level= "landscape",
what = c("lsm_l_ed"))
I need to have a visualization of the progress for the last function (#moving window analysis)
The function window_lsm() uses raster::focal() internally, which doesn't provide a progress bar itself. So without writing your own loop/moving window function I think this won't be possible, unfortunately.
As already mentioned above, the progress argument in window_lsm() refers to layers and metrics only, but not the moving window.
Not familiar with this package, but window_lsm() has an argument progress which will "print progress report" when TRUE.
Otherwise, to the best of my knowledge it's not possible to implement a true progress bar without any kind of iteration / loop. The one other option I see would be to look at the source of window_lsm(); find the outermost loop (if there is one); define your own local version of the function; and insert a progress bar incremented inside the loop (e.g. using the progress package). (Obviously, you wouldn't want to redistribute this without looking into the licensing / discussing with package devs.)
I guess another option would be to somehow develop an estimate of how long the operation might take, e.g., based on the size of your raster, then run a countdown timer in a parallel process? My hunch is this would be hard to implement and not especially accurate.

Is there a way to see a 'live' calculation for the code in RStudio?

I have a code that runs a monte carlo simulation between A/B/C, and I modified it so now it will run a MC sim between A/B/C/D. However, the code works fine with A/B/C, but if I add the D category the code just dies. It brings up the UI that it is supposed to but when I click 'compute' (action button) the program stops doing anything. it doesn't close, but it just doesn't do anything.
I am wondering if the issue isn't necessarily the code but what I am asking the code to do. An MCMC with 100k samples, 4 conditions becomes 100000^4 and things get computationally heavy very quickly.
I am hoping for a recommendation that someone may have where I can see what the R code is doing in sort of a 'live stream'. It doesn't return any errors, but I am hoping to be able to see when I add the D category the code will say 'I'm working on it, but it's taking a long time.' But I don't even know where to begin to look for something like that.

Is it possible to get RStudio to show function arguments and descriptions for custom functions?

The code completion in RStudio is great, and I really like how a popover appears to describe the arguments for the function inputs. For example, if one types matrix( and then presses "tab", a list of arguments for the matrix() function appears, along with a description of the input. Say, nrow= is selected, then the adjoining window describes the nrow input as "the desired number of rows.".
Can I get RStudio to do this for my custom functions? Would I have to create a package to achieve this effect?
Say I have a file full of custom functions, myCustomFunctions.R, and I store all my miscellaneous helper functions in there. I want to be able to add meta data for my functions so that this helper window also describes my function inputs.
To add to Hadley's answer in the comments, Rstudio is mining specific portions of the help files to generate the helper window. Specifically, tabbing before the parentheses brings up the "Usage" and "Description" sections and tabbing inside the parentheses or after a comma brings up the "Arguments" section. Therefore, not only does a package need to be made, but the help files must be generated to take advantage of this feature.
Following up Hadley: even if the functions are only for your own use, it's worth package-izing them. You will then get a lot of useful stuff for free, above and beyond the package documentation system: things like version control, unit testing, portability, shareability ... I could go on. There's a small potential barrier which you have to get over before you can get back to the fun part (i.e. hacking your own neat stuff), but it's worth the investment of time.
Hadley has public-spiritedly put his Packages book online with step by step descriptions of how to access all the goodies I've mentioned. Hopefully you'll decide it's worth paying for (I did).

Strategies for repeating large chunk of analysis

I find myself in the position of having completed a large chunk of analysis and now need to repeat the analysis with slightly different input assumptions.
The analysis, in this case, involves cluster analysis, plotting several graphs, and exporting cluster ids and other variables of interest. The key point is that it is an extensive analysis, and needs to be repeated and compared only twice.
I considered:
Creating a function. This isn't ideal, because then I have to modify my code to know whether I am evaluating in the function or parent environments. This additional effort seems excessive, makes it harder to debug and may introduce side-effects.
Wrap it in a for-loop. Again, not ideal, because then I have to create indexing variables, which can also introduce side-effects.
Creating some pre-amble code, wrapping the analysis in a separate file and source it. This works, but seems very ugly and sub-optimal.
The objective of the analysis is to finish with a set of objects (in a list, or in separate output files) that I can analyse further for differences.
What is a good strategy for dealing with this type of problem?
Making code reusable takes some time, effort and holds a few extra challenges like you mention yourself.
The question whether to invest is probably the key issue in informatics (if not in a lot of other fields): do I write a script to rename 50 files in a similar fashion, or do I go ahead and rename them manually.
The answer, I believe, is highly personal and even then, different case by case. If you are easy on the programming, you may sooner decide to go the reuse route, as the effort for you will be relatively low (and even then, programmers typically like to learn new tricks, so that's a hidden, often counterproductive motivation).
That said, in your particular case: I'd go with the sourcing option: since you plan to reuse the code only 2 times more, a greater effort would probably go wasted (you indicate the analysis to be rather extensive). So what if it's not an elegant solution? Nobody is ever going to see you do it, and everybody will be happy with the swift results.
If it turns out in a year or so that the reuse is higher than expected, you can then still invest. And by that time, you will also have (at least) three cases for which you can compare the results from the rewritten and funky reusable version of your code with your current results.
If/when I do know up front that I'm going to reuse code, I try to keep that in mind while developing it. Either way I hardly ever write code that is not in a function (well, barring the two-liners for SO and other out-of-the-box analyses): I find this makes it easier for me to structure my thoughts.
If at all possible, set parameters that differ between sets/runs/experiments in an external parameter file. Then, you can source the code, call a function, even utilize a package, but the operations are determined by a small set of externally defined parameters.
For instance, JSON works very well for this and the RJSONIO and rjson packages allow you to load the file into a list. Suppose you load it into a list called parametersNN.json. An example is as follows:
{
"Version": "20110701a",
"Initialization":
{
"indices": [1,2,3,4,5,6,7,8,9,10],
"step_size": 0.05
},
"Stopping":
{
"tolerance": 0.01,
"iterations": 100
}
}
Save that as "parameters01.json" and load as:
library(RJSONIO)
Params <- fromJSON("parameters.json")
and you're off and running. (NB: I like to use unique version #s within my parameters files, just so that I can identify the set later, if I'm looking at the "parameters" list within R.) Just call your script and point to the parameters file, e.g.:
Rscript --vanilla MyScript.R parameters01.json
then, within the program, identify the parameters file from the commandArgs() function.
Later, you can break out code into functions and packages, but this is probably the easiest way to make a vanilla script generalizeable in the short term, and it's a good practice for the long-term, as code should be separated from the specification of run/dataset/experiment-dependent parameters.
Edit: to be more precise, I would even specify input and output directories or files (or naming patterns/prefixes) in the JSON. This makes it very clear how one set of parameters led to one particular output set. Everything in between is just code that runs with a given parametrization, but the code shouldn't really change much, should it?
Update:
Three months, and many thousands of runs, wiser than my previous answer, I'd say that the external storage of parameters in JSON is useful for 1-1000 different runs. When the parameters or configurations number in the thousands and up, it's better to switch to using a database for configuration management. Each configuration may originate in a JSON (or XML), but being able to grapple with different parameter layouts requires a larger scale solution, for which a database like SQLite (via RSQLite) is a fine solution.
I realize this answer is overkill for the original question - how to repeat work only a couple of times, with a few parameter changes, but when scaling up to hundreds or thousands of parameter changes in ongoing research, more extensive tools are necessary. :)
I like to work with combination of a little shell script, a pdf cropping program and Sweave in those cases. That gives you back nice reports and encourages you to source. Typically I work with several files, almost like creating a package (at least I think it feels like that :) . I have a separate file for the data juggling and separate files for different types of analysis, such as descriptiveStats.R, regressions.R for example.
btw here's my little shell script,
#!/bin/sh
R CMD Sweave docSweave.Rnw
for file in `ls pdfs`;
do pdfcrop pdfs/"$file" pdfs/"$file"
done
pdflatex docSweave.tex
open docSweave.pdf
The Sweave file typically sources the R files mentioned above when needed. I am not sure whether that's what you looking for, but that's my strategy so far. I at least I believe creating transparent, reproducible reports is what helps to follow at least A strategy.
Your third option is not so bad. I do this in many cases. You can build a bit more structure by putting the results of your pre-ample code in environments and attach the one you want to use for further analysis.
An example:
setup1 <- local({
x <- rnorm(50, mean=2.0)
y <- rnorm(50, mean=1.0)
environment()
# ...
})
setup2 <- local({
x <- rnorm(50, mean=1.8)
y <- rnorm(50, mean=1.5)
environment()
# ...
})
attach(setup1) and run/source your analysis code
plot(x, y)
t.test(x, y, paired = T, var.equal = T)
...
When finished, detach(setup1) and attach the second one.
Now, at least you can easily switch between setups. Helped me a few times.
I tend to push such results into a global list.
I use Common Lisp but then R isn't so different.
Too late for you here, but I use Sweave a lot, and most probably I'd have used a Sweave file from the beginning (e.g. if I know that the final product needs to be some kind of report).
For repeating parts of the analysis a second and third time, there are then two options:
if the results are rather "independent" (i.e. should produce 3 reports, comparison means the reports are inspected side by side), and the changed input comes in the form of new data files, that goes into its own directory together with a copy of the Sweave file, and I create separate reports (similar to source, but feels more natural for Sweave than for plain source).
if I rather need to do the exactly same thing once or twice again inside one Sweave file I'd consider reusing code chunks. This is similar to the ugly for-loop.
The reason is that then of course the results are together for the comparison, which would then be the last part of the report.
If it is clear from the beginning that there will be some parameter sets and a comparison, I write the code in a way that as soon as I'm fine with each part of the analysis it is wrapped into a function (i.e. I'm acutally writing the function in the editor window, but evaluate the lines directly in the workspace while writing the function).
Given that you are in the described situation, I agree with Nick - nothing wrong with source and everything else means much more effort now that you have it already as script.
I can't make a comment on Iterator's answer so I have to post it here. I really like his answer so I made a short script for creating the parameters and exporting them to external JSON files. And I hope someone finds this useful: https://github.com/kiribatu/Kiribatu-R-Toolkit/blob/master/docs/parameter_configuration.md

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