I have a specific computer vision problem that I want to try solving using some pre-trained models. The Flux.jl docs don't actually have any pre-trained models in them like some of the other ML frameworks (PyTorch as an example). How would I access those sort of pertained models in Flux?
In the Flux ecosystem, the functionality for something like pre-trained computer vision models has been extrapolated out into a separate package called MetalHead.jl: https://github.com/FluxML/Metalhead.jl
Per the docs there, you can create a VGG19 model by doing:
julia> vgg19 = VGG19()
VGG19()
and then you can pass the model to something like the classify function along with an input image for a validation test.
Related
I'm trying to build a random forest using model based regression trees in partykit package. I have built a model based tree using mob() function with a user defined fit() function which returns an object at the terminal node.
In partykit there is cforest() which uses only ctree() type trees. I want to know if it is possible to modify cforest() or write a new function which builds random forests from model based trees which returns objects at the terminal node. I want to use the objects in the terminal node for predictions. Any help is much appreciated. Thank you in advance.
Edit: The tree I have built is similar to the one here -> https://stackoverflow.com/a/37059827/14168775
How do I build a random forest using a tree similar to the one in above answer?
At the moment, there is no canned solution for general model-based forests using mob() although most of the building blocks are available. However, we are currently reimplementing the backend of mob() so that we can leverage the infrastructure underlying cforest() more easily. Also, mob() is quite a bit slower than ctree() which is somewhat inconvenient in learning forests.
The best alternative, currently, is to use cforest() with a custom ytrafo. These can also accomodate model-based transformations, very much like the scores in mob(). In fact, in many situations ctree() and mob() yield very similar results when provided with the same score function as the transformation.
A worked example is available in this conference presentation:
Heidi Seibold, Achim Zeileis, Torsten Hothorn (2017).
"Individual Treatment Effect Prediction Using Model-Based Random Forests."
Presented at Workshop "Psychoco 2017 - International Workshop on Psychometric Computing",
WU Wirtschaftsuniversität Wien, Austria.
URL https://eeecon.uibk.ac.at/~zeileis/papers/Psychoco-2017.pdf
The special case of model-based random forests for individual treatment effect prediction was also implemented in a dedicated package model4you that uses the approach from the presentation above and is available from CRAN. See also:
Heidi Seibold, Achim Zeileis, Torsten Hothorn (2019).
"model4you: An R Package for Personalised Treatment Effect Estimation."
Journal of Open Research Software, 7(17), 1-6.
doi:10.5334/jors.219
I tried to build a pre-trained core-ml model with the help of create ML framework, but the model created is not updatable, Is there a way to create a pre-trained core-ml model which can be updated on the device itself (newly introduced feature in Core-ML 3) ?
Not directly with Create ML, you'll have to use coremltools to make the model updatable. See here for examples: https://github.com/apple/coremltools/tree/main/examples
However... this will only work for neural networks and k-nearest neighbors models. Create ML does not actually produce these kinds of models (at the moment).
For example, an image classifier trained with Create ML is a GLM on top of a fixed neural network. You cannot make GLM models updatable at this point.
So in short, no, you can't make models trained with Create ML updatable.
Like in decision tree we can see or visualize the node splits , I want to do something similar . But I am using SparkR and it does not have decision trees. So I am planning to use random forest with 1 tree as parameter and run on SparkR, then save the model and use getTree to see the node splits and further visualize using ggplot.
The short answer is no.
Models built with SparkR are not compatible with ones built with the respective R packages, in this case randomForest; hence, you will not be able to use the getTree function from the latter to visualize a tree from a random forest built with SparkR.
On a different level: I am surprised that decision trees have still not found their way into SparkR - they seem to be ready since several months now in the Github repo; but even when they are, they are not expected to offer methods for visualizing trees, and you will still not be able to use functions from other R packages for that purpose.
I'm currently working on trust prediction in social networks - from obvious reasons I model this problem as data stream. What I want to do is to "update" my trained model using old model + new chunk of data stream. Classifiers that I am using are SVM, NB (e1071 implementation), neural network (nnet) and C5.0 decision tree.
Sidenote: I know that this solution is possible using RMOA package by defining "model" argument in trainMOA function, but I don't think I can use it with those classifiers implementations (if I am wrong please correct me).
According to strange SO rules, I can't post it as comment, so be it.
Classifiers that you've listed need full data set at the time you train a model, so whenever new data comes in, you should combine it with previous data and retrain the model. What you are probably looking for is online machine learning. One of the very popular implementations is Vowpal Wabbit, it also has bindings to R.
A newbie question on WSO2 and 'R'....
I have a customer where they are looking to build some statistical models using 'R'. These models are mostly associated with customer scoring, i.e. sucking in a table of customer data with behavioural attributes as columns, and spitting out a 'score' for each customer.
Two questions on this:
Can 'R' models by deployed like rules in a service model?
Could you deploy R models into a WSO2 middleware, and if so, how and where?
TIA
Note: I'm not familiar with wso2 but I'm with R.
The answer to your question very much depends on what type of models you would like to deploy. The easiest ones are models such as linear/logistic regression followed by decision trees.
The reason they are easy is because for linear & logistic regression you get a nice formula you can plug-in to any programming interface. An example prediction formula might be like the following:
customer_predicted_life_time_value =
17.25+2.365*num_of_products_held-16.12*time_at_address+25.36*monthly_income.
Similarly, decision trees can be easily exported as a bunch of if-then-else rules (there at least a couple of packages in R which will translate the R decision tree model into rules).
You could technically be able to deploy randomForest too in the form of rules but that will be cumbersome if you want to implenent using rules.