mlr3pipelines | Dataflow Programming for Machine Learning in R | Machine Learning library
kandi X-RAY | mlr3pipelines Summary
kandi X-RAY | mlr3pipelines Summary
Single computational steps can be represented as so-called PipeOps, which can then be connected with directed edges in a Graph. The scope of mlr3pipelines is still growing; currently supported features are:.
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
Currently covering the most popular Java, JavaScript and Python libraries. See a Sample of mlr3pipelines
mlr3pipelines Key Features
mlr3pipelines Examples and Code Snippets
Community Discussions
Trending Discussions on mlr3pipelines
QUESTION
I using the mlr3
package for autotuning ML models (mlr3pipelines graph, to be more correct).
It is very hard to reproduce the problem because the error occurs occasionally. The same code sometimes returns an error and sometimes doesn't.
Here is the code snippet
...ANSWER
Answered 2022-Mar-14 at 22:09There is a fixed buffer for loading RNG functions in uuid
which will fail if there are too many DLLs loaded already. A simple work-around is to run
QUESTION
I am a beginner on mlr3 and am facing problems while running AutoFSelector learner associated to glmnet on a classification task containing >2000 numeric variables. I reproduce this error while using the simpler mlr3 predefined task Sonar. For note, I am using R version 4.1.2 (2021-11-01)on macOS Monterey 12.1. All required packages have been loaded on CRAN.
...ANSWER
Answered 2022-Jan-24 at 18:05This is a problem specific to glmnet
. glmnet
requires at least two features to fit a model, but in at least one configuration (the first ones in a sequential forward search) you only have one feature.
There are two possibilities to solve this:
- Open an issue in mlr3fselect and request a new argument
min_features
(there already ismax_features
) to be able to start the search with 2 or more features. - Augment the base learner with a fallback which gets fitted if the base learner fails. Here is fallback to a simple logistic regression:
QUESTION
I have some following codes. I met error when save trained model.
It's only error when i using lightgbm
.
ANSWER
Answered 2021-Nov-01 at 08:17QUESTION
My codes in following
...ANSWER
Answered 2021-Jun-08 at 09:22To be able to fiddle with the models after resampling its best to call resample with store_models = TRUE
Using your example
QUESTION
I try to optimize the averaged prediction of two logistic regressions in a classification task using a superlearner.
My measure of interest is classif.auc
The mlr3
help file tells me (?mlr_learners_avg
)
Predictions are averaged using weights (in order of appearance in the data) which are optimized using nonlinear optimization from the package "nloptr" for a measure provided in measure (defaults to classif.acc for LearnerClassifAvg and regr.mse for LearnerRegrAvg). Learned weights can be obtained from $model. Using non-linear optimization is implemented in the SuperLearner R package. For a more detailed analysis the reader is referred to LeDell (2015).
I have two questions regarding this information:
When I look at the source code I think
LearnerClassifAvg$new()
defaults to"classif.ce"
, is that true? I think I could set it toclassif.auc
withparam_set$values <- list(measure="classif.auc",optimizer="nloptr",log_level="warn")
The help file refers to the
SuperLearner
package and LeDell 2015. As I understand it correctly, the proposed "AUC-Maximizing Ensembles through Metalearning" solution from the paper above is, however, not impelemented inmlr3
? Or do I miss something? Could this solution be applied inmlr3
? In themlr3
book I found a paragraph regarding calling an external optimization function, would that be possible forSuperLearner
?
ANSWER
Answered 2021-Apr-20 at 10:07As far as I understand it, LeDell2015 proposes and evaluate a general strategy that optimizes AUC as a black-box function by learning optimal weights. They do not really propose a best strategy or any concrete defaults so I looked into the defaults of the SuperLearner package's AUC optimization strategy.
Assuming I understood the paper correctly:
The LearnerClassifAvg
basically implements what is proposed in LeDell2015 namely, it optimizes the weights for any metric using non-linear optimization. LeDell2015 focus on the special case of optimizing AUC. As you rightly pointed out, by setting the measure to "classif.auc"
you get a meta-learner that optimizes AUC. The default with respect to which optimization routine is used deviates between mlr3pipelines and the SuperLearner package, where we use NLOPT_LN_COBYLA
and SuperLearner ... uses the Nelder-Mead method via the optim
function to minimize rank loss (from the documentation).
So in order to get exactly the same behaviour, you would need to implement a Nelder-Mead
bbotk::Optimizer
similar to here that simply wraps stats::optim
with method Nelder-Mead
and carefully compare settings and stopping criteria. I am fairly confident that NLOPT_LN_COBYLA
delivers somewhat comparable results, LeDell2015 has a comparison of the different optimizers for further reference.
Thanks for spotting the error in the documentation. I agree, that the description is a little unclear and I will try to improve this!
QUESTION
I try to solve a common problem in medicine: the combination of a prediction model with other sources, eg, an expert opinion [sometimes heavily emphysised in medicine], called superdoc
predictor in this post.
This could be solved by stack a model with a logistic regression (that enters the expert opinion) as described on page 26 in this paper:
Afshar P, Mohammadi A, Plataniotis KN, Oikonomou A, Benali H. From Handcrafted to Deep-Learning-Based Cancer Radiomics: Challenges and Opportunities. IEEE Signal Process Mag 2019; 36: 132–60. Available here
I've tried this here without considering overfitting (I did not apply out of fold predictions of the lower learner):
Example data
...ANSWER
Answered 2021-Mar-17 at 00:10I think mlr3
/ mlr3pipelines
is well suited for your task. It appears that what you are missing is mainly the PipeOpSelect
/ po("select")
, which lets you extract features based on their name or other properties and makes use of Selector
objects. Your code should probably look something like
QUESTION
I have a mlr3 task
...ANSWER
Answered 2020-Nov-05 at 19:38This is quite straightforward to do using PipeOpColApply
.
We need to define a function that will take the provided input and perform the requested operation (applicator).
QUESTION
I want to train models on different subsets of data using mlr3
, and I was wondering if there a way to train models on different subsets of data in a pipeline.
What I want to do is similar to the example from R for Data Science - Chapter 25: Many models. Say we use the same data set, gapminder
, a data set containing different variables for countries around the world, such as GDP and life expectancy. If I wanted to train models for life expectancy for each country, is there an easy way to create such a pipeline using mlr3
?
Ideally, I want to use mlr3pipelines
to create a branch in the graph for each subset (e.g. a separate branch for each country) with a model at the end. Therefore, the final graph will start at a single node, and have n
trained learners at the end nodes, one for each group (i.e. country) in the data set, or a final node that aggregates the results. I would also expect it to work for new data, for example if we obtain new data in the future for 2020, I would want it to be able to create predictions for each country using the model trained for that specific country.
All the mlr3
examples I have found seem to deal with models for the entire data set, or have models trained with all the groups in the training set.
Currently, I am just manually creating a separate task for each group of data, but it would be nice to have the data subsetting step incorporated into the modelling pipeline.
...ANSWER
Answered 2020-Oct-01 at 02:53It would help if you had functions from these two packages: dplyr
and tidyr
. The following code shows you how to train multiple models by country:
QUESTION
# Packages
library(dplyr)
library(recipes)
# toy dataset, with A being multicolored
df <- tibble(name = c("A", "A", "A", "B", "C"), color = c("green", "yellow", "purple", "green", "blue"))
#> # A tibble: 5 x 2
#> name color
#>
#> 1 A green
#> 2 A yellow
#> 3 A purple
#> 4 B green
#> 5 C blue
...ANSWER
Answered 2020-Aug-17 at 08:52I wrote the following custom step for the recipes package.
QUESTION
R version used: 3.6.3, mlr3 version: 0.4.0-9000, mlr3proba version: 0.1.6.9000, mlr3pipelines version: 0.1.2 and xgboost version: 0.90.0.2 (as stated on Rstudio package manager)
I have deployed the following graph pipeline:
...ANSWER
Answered 2020-Jul-29 at 08:51The problem lies in distr6 here, please install the latest versions of distr6 (1.4.2) and mlr3proba (0.2.0) from CRAN and then try again.
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install mlr3pipelines
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page