In order to leverage FCN facilities for an image processing project, firstly I headed to use MatConvNet. However, in the preparation steps I found that MATLAB provided a new function (fcnLayers) to do so.
Can fcnLayers and its functionality be compared with MatConvNet? Specifically, I mean that is it possible to train models or use pre-trained ones?
Finally, may I achieve same result by using each of them?
Related
I am trying to implement bayesian optimization using gauss process regression, and I want to try the multiple output GP firstly.
There are many softwares that implemented GP, like the fitrgp function in MATLAB and the ooDACE toolbox.
But I didn't find any available softwares that implementd the so called multiple output GP, that is, the Gauss Process Model that predict vector valued functions.
So, Are there any softwares that implemented the multiple output gauss process that I can use directly?
I am not sure my answer will help you as you seem to search matlab libraries.
However, you can do co-kriging in R with gstat. See http://www.css.cornell.edu/faculty/dgr2/teach/R/R_ck.pdf or https://github.com/cran/gstat/blob/master/demo/cokriging.R for more details about usage.
The lack of tools to do cokriging is partly due to the relative difficulty to use it. You need more assumptions than for simple kriging: in particular, modelling the dependence between in of the cokriged outputs via a cross-covariance function (https://stsda.kaust.edu.sa/Documents/2012.AGS.JASA.pdf). The covariance matrix is much bigger and you still need to make sure that it is positive definite, which can become quite hard depending on your covariance functions...
I am trying to learn how to use support vector machines in matlab. I have the bioinformatics toolbox, which has SVM functions svmtrain and svmclassify.
I managed to successfully use it for some reference data sets, with some nice accuracy. When I try to use the svm on my actual data the training never stops. My data set is 400 instances in 25 dimensions, so it should not take very long?!
Can I use other solvers in matlab? I dont want to buy new toolbox please ...
There are several things that may cause problems for training, but it should not run infinitely. Do you get any errors when using the solver?
With regard to alternatives: LIBSVM has an interface to matlab. This is a state-of-the-art library with thousands of users. I highly recommend it, because it is easy to install/use and offers additional functionality for parameter tuning and more.
I'm working on a new model and would like to use classperf to check the performance of my classifier. How do I make it use my classifier as opposed to one of the built-in ones? All the examples I found online use classifiers that are included in MATLAB. I want to use K-fold to test it.
It isn't clear form the MATLAB documentation how to do this, though you can edit functions like knnclassify or svmclassify to see how they were written, and try to emulate that functionality.
Alternatively, there's a free MATLAB pattern recognition toolbox that uses objects to represent classifiers:
http://www.mathworks.com/matlabcentral/linkexchange/links/2947-pattern-recognition-toolbox
And you can make a new classifier by sub-classing the base classifier object: prtClass.
Then you can do:
c = myClassifier;
yGuess = c.kfolds(dataSet,10); %10 fold X-val
(Full disclosure, I'm an author of the PRT toolbox)
I was wondering if anyone has managed to use the OpenCV implementation of Latent SVM Detector (http://docs.opencv.org/modules/objdetect/doc/latent_svm.html) successfully. There is a sample code that shows how to utilize the library but the problem is that the sample code uses a ready-made detector model that was generated using MatLab. Can some one guide me through the steps on how to generate my own detector model?
The MATLAB implementation of LatSVM by the authors of the paper has a train script called pascal. There is a README with the tarball explaining its usage:
Using the learning code
=======================
1. Download and install the 2006-2011 PASCAL VOC devkit and dataset.
(you should set VOCopts.testset='test' in VOCinit.m)
2. Modify 'voc_config.m' according to your configuration.
3. Start matlab.
4. Run the 'compile' function to compile the helper functions.
(you may need to edit compile.m to use a different convolution
routine depending on your system)
5. Use the 'pascal' script to train and evaluate a model.
example:
>> pascal('bicycle', 3); % train and evaluate a 6 component bicycle model
The learning code saves a number of intermediate models in a model cache
directory defined in 'voc_config.m'.
For more information, visit the authors website. The page also contain the paper of this method.
I am trying to do some text classification with SVMs in MATLAB and really would to know if MATLAB has any methods for feature selection(Chi Sq.,MI,....), For the reason that I wan to try various methods and keeping the best method, I don't have time to implement all of them. That's why I am looking for such methods in MATLAB.Does any one know?
svmtrain
MATLAB has other utilities for classification like cluster analysis, random forests, etc.
If you don't have the required toolbox for svmtrain, I recommend LIBSVM. It's free and I've used it a lot with good results.
The Statistics Toolbox has sequentialfs. See also the documentation on feature selection.
A similar approach is dimensionality reduction. In MATLAB you can easily perform PCA or Factor analysis.
Alternatively you can take a wrapper approach to feature selection. You would search through the space of features by taking a subset of features each time, and evaluating that subset using any classification algorithm you decide (LDA, Decision tree, SVM, ..). You can do this as an exhaustively or using some kind of heuristic to guide the search (greedy, GA, SA, ..)
If you have access to the Bioinformatics Toolbox, it has a randfeatures function that does a similar thing. There's even a couple of cool demos of actual use cases.
May be this might help:
There are two ways of selecting the features in the classification:
Using fselect.py from libsvm tool directory (http://www.csie.ntu.edu.tw/~cjlin/libsvmtools/#feature_selection_tool)
Using sequentialfs from statistics toolbox.
I would recommend using fselect.py as it provides more options - like automatic grid search for optimum parameters (using grid.py). It also provides an F-score based on the discrimination ability of the features (see http://www.csie.ntu.edu.tw/~cjlin/papers/features.pdf for details of F-score).
Since fselect.py is written in python, either you can use python interface or as I prefer, use matlab to perform a system call to python:
system('python fselect.py <training file name>')
Its important that you have python installed, libsvm compiled (and you are in the tools directory of libsvm which has grid.py and other files).
It is necessary to have the training file in libsvm format (sparse format). You can do that by using sparse function in matlab and then libsvmwrite.
xtrain_sparse = sparse(xtrain)
libsvmwrite('filename.txt',ytrain,xtrain_sparse)
Hope this helps.
For sequentialfs with libsvm, you can see this post:
Features selection with sequentialfs with libsvm