Is there a python package handling binary decision diagrams (BDDs) and zero suppressed binary decision diagrams (ZDDs), as in Knuth volume 4?
I know networkx can handle DAGs cleanly, but I'm looking for something that handles the internal garbage keeping of ZDDs, constructions from the algebra of set families (Knuth), construction of BDDs from other types of decision diagrams, and maybe some primitive ZDDs and queries (such as sampling and counting).
There are some packages in other languages: Java and C++. (Edits extending this list would be welcome.)
Edit -- several promising tools listed here: https://github.com/johnyf/tool_lists/blob/master/bdd.md
Edit2 -- Graphillion, a python package recommended by Minato himself in this slides, may be the canonical answer. Especially as it comes with this endearing tutorial video (that comes with this backstory).
Yes. Graphillion should do it.
What's your source of BDD/ZDD? If say for example the source is blif, blif should be translated to x and then the x should be translated to ZDD.
For you, you have to figure out what x is.
Related
Does anyone know if there is a Python-based procedure to decompose time series utilizing STL (Seasonal-Trend-Loess) method?
I saw references to a wrapper program to call the stl function
in R, but I found that to be unstable and cumbersome from the environment set-up perspective (Python and R together). Also, link was 4 years old.
Can someone point out something more recent (e.g. sklearn, spicy, etc.)?
I haven't tried STLDecompose but I took a peek at it and I believe it uses a general purpose loess smoother. This is hard to do right and tends to be inefficient. See the defunct STL-Java repo.
The pyloess package provides a python wrapper to the same underlying Fortran that is used by the original R version. You definitely don't need to go through a bridge to R to get this same functionality! This package is not actively maintained and I've occasionally had trouble getting it to build on some platforms (thus the fork here). But once built, it does work and is the fastest one you're likely to find. I've been tempted to modify it to include some new features, but just can't bring myself to modify the Fortran (which is pre-processed RATFOR - very assembly-language like Fortran, and I can't find a RATFOR preprocessor anywhere).
I wrote a native Java implementation, stl-decomp-4j, that can be called from python using the pyjnius package. This started as a direct port of the original Fortran, refactored to a more modern programming style. I then extended it to allow quadratic loess interpolation and to support post-decomposition smoothing of the seasonal component, features that are described in the original paper but that were not put into the Fortran/R implementation. (They apparently are in the S-plus implementation, but few of us have access to that.) The key to making this efficient is that the loess smoothing simplifies when the points are equidistant and the point-by-point smoothing is done by simply modifying the weights that one is using to do the interpolation.
The stl-decomp-4j examples include one Jupyter notebook demonstrating how to call this package from python. I should probably formalize that as a python package but haven't had time. Quite willing to accept pull requests. ;-)
I'd love to see a direct port of this approach to python/numpy. Another thing on my "if I had some spare time" list.
Here you can find an example of Seasonal-Trend decomposition using LOESS (STL), from statsmodels.
Basicaly it works this way:
from statsmodels.tsa.seasonal import STL
stl = STL(TimeSeries, seasonal=13)
res = stl.fit()
fig = res.plot()
There is indeed:
https://github.com/jrmontag/STLDecompose
In the repo you will find a jupyter notebook for usage of the package.
RSTL is a Python port of R's STL: https://github.com/ericist/rstl. It works pretty well except it is 3~5 times slower than R's STL according to the author.
If you just want to get lowess trend line, you can just use Statsmodels' lowess function
https://www.statsmodels.org/dev/generated/statsmodels.nonparametric.smoothers_lowess.lowess.html.
I am working on a teaching tool for binary decision diagrams in which there is also a feature for variable reordering. Can anyone suggest a suitable library which implements variable reordering while building the tree or some kind of algorithm which implements the same ?
It would be best if I could work with a library like pyeda, buDDy or pycudd because I am already familiar with these libraries.
Thanks and comment if you need any kind of clarification..
Have you looked at dd, by Ioannis Filippidis?
I'm the author of pyeda. Implementing ROBDDs in Python was definitely fun, and can probably have some educational value, but it definitely doesn't do any automatic variable reordering, so if that's a requirement I would recommend looking at dd or the other ones on your list.
My group at University of Maribor is producing BDD Scout ( http://biddy.meolic.com/ ), a tool for visualization of BDDs. Currently, ROBDDs with complemented edges and 0-sup-BDDs with complemented edges are supported. Conversions are supported. Reordering (i.e. variable swapping and sifting algorithm) is supported for both of them. BDD Scout work on GNU/Linux an MS Windows (source and binary packages are available). We hope that our tool one day becomes a good teaching tool but we need some feedback to improve it. Besides the robustness the set of the functionalities is the most critical part to improve. If you will find some time to try it do not hesitate to give us any comments and questions.
Is there any python library with functions to perform fixed or random effects meta-analysis?
I have search through google, pypi and other sources but it seems that the most popular python stats libraries lack this functionality.
It would be great if it also provide graphical solutions to produce funnel plots and forest plots.
Forest plot example:
It thought of something similar to R package rmeta
I've found some people creating their own functions manually, but it isn't a actual library. In addition, metasoft was promising, but it uses python only to convert between formats.
Just to say, it seems the mostly widely used tool is R's metafor, which provides seemingly every possible method used and includes essential plotting functions.
In Python, PythonMeta the backend for a web-based tool PyMeta which offers many of the methods (fixed and random effects, various data types) found in metafor.
This PyMARE project is still under development but does provide various fixed and random effects meta-analysis estimators (this is a spin-off from the rather more mature NiMARE tool for neuroimaging meta-analysis).
statsmodels now also offers some options for meta-analysis and visualization of its results, more information here:
https://www.statsmodels.org/devel/examples/notebooks/generated/metaanalysis1.html
I have been very happy with some language translations I've done with Prolog, but long ago. I'm now using Python for general purpose programming. The area is DNA sequencing data processing, but that's besides the point.
I am interested in using a DCG (definite clause grammar) for translation into a target language. (A DCG is very close to being a set of Prolog predicates, and a DCG to Prolog interpretation layer is almost trivial, as I recall.) The method I used was to parse an input language, and at the same time as parsing the input expressions, build a network structure to represent a deeper model of the expression. Another grammar then served to elaborate that model into a valid expression in the target language.
This time, though, I'm looking to do just the second half, to take an internal model (in a network of Python objects) and translate them into a target language. (This target language is a workflow configuration language, incidentally, and the network of objects are those used by a pre-existing less general workflow engine that I hope to abandon.)
So, are there any modern, supported Prolog implementations that cleanly interface to Python?
YAP provides a Python interface package:
http://www.dcc.fc.up.pt/~vsc/yap/
If you want to try it, I suggest you start with use the current git version found at:
https://github.com/vscosta/yap-6.3
Some examples are provided with the distribution:
https://github.com/vscosta/yap-6.3/tree/master/packages/python/examples
I will soon be starting a final year Engineering project, consisting of the real-time tracking of objects moving on a 2D-surface. The objects will be registered by my algorithm using feature extraction.
I am trying to do some research to decide whether I should use MATLAB or use Python Numpy (Numerical Python). Some of the factors I am taking into account:
1.) Experience
I have reasonable experience in both, but perhaps more experience in image processing using Numpy. However, I have always found MATLAB to be very intuitive and easy to pick up.
2.) Real-Time abilities
It is very important that my choice be able to support the real-time acquisition of video data from an external camera. I found this link for MATLAB showing how to do it. I am sure that the same would be possible for Python, perhaps using the OpenCV library?
3.) Performance
I have heard, although never used, that MATLAB can easily split independent calculations across multiple cores. I should think that this would be very useful, and I am not sure whether the same is equally simple for Numpy?
4.) Price
I know that there is a cost associated with MATLAB, but I will be working at a university and thus will have access to full MATLAB without any cost to myself, so price is not a factor.
I would greatly appreciate any input from anyone who has done something similar, and what your experience was.
Thanks!
Python (with NumPy, SciPy and MatPlotLib) is the new Matlab. So I strongly recommend Python over Matlab.
I made the change over a year ago and I am very happy with the results.
Here it is a short pro/con list for Python and Matlab
Python pros:
Object Oriented
Easy to write large and "real" programs
Open Source (so it's completely free to use)
Fast (most of the heavy computation algorithms have a python wrapper to connect with C libraries e.g. NumPy, SciPy, SciKits, libSVM, libLINEAR)
Comfortable environment, highly configurable (iPython, python module for VIM, ...)
Fast growing community of Python users. Tons of documentation and people willing to help
Python cons:
Could be a pain to install (especially some modules in OS X)
Plot manipulation is not as nice/easy as in Matlab, especially 3D plots or animations
It's still a script language, so only use it for (fast) prototyping
Python is not designed for multicore programming
Matlab pros:
Very easy to install
Powerful Toolboxes (e.g. SignalProcessing, Systems Biology)
Unified documentation, and personalized support as long as you buy the licence
Easy to have plot animations and interactive graphics (that I find really useful for running experiments)
Matlab cons:
Not free (and expensive)
Based on Java + X11, which looks extremely ugly (ok, I accept I'm completely biased here)
Difficult to write large and extensible programs
A lot of Matlab users are switching to Python :)
I would recommend python.
I switched from MATLAB -> python about 1/2 way through my phd, and do not regret it. At the most simplistic, python is a much nicer language, has real objects, etc.
If you expect to be doing any parts of your code in c/c++ I would definitely recommend python. The mex interface works, but if your build gets complicated/big it starts to be a pain and I never sorted out how to effectively debug it. I also had great difficulty with mex+allocating large blocks interacting with matlab's memory management (my inability to fix that issue is what drove me to switch).
As a side note/self promotion, I have Crocker-Grier in c++ (with swig wrappers) and pure python.
If you're experienced with both languages it's not really a decision criterion.
Matlab has problems coping with real time settings especially since most computer vision algorithms are very costly. This is the advantage of using a tried and tested library such as OpenCV where many of the algorithms you'll be using are efficiently implemented. Matlab offers the possibility of compiling code into Mex-files but that is a lot of work.
Matlab has parallel for loops parfor which makes multicore processing easy (or at least easier). But the question is if that will suffice to get real-time speeds.
No comment.
The main advantage of Matlab is that you'll obtain a running program very quickly due to its good documentation. But I found that code reusability is bad with Matlab unless you put a heavy emphasis on it.
I think the final decision has to be if you have to/can run your algorithm real-time which I doubt in Matlab, but that depends on what methods you're planning to use.
Others have made a lot of great comments (I've opined on this topic before in another answer https://stackoverflow.com/a/5065585/392949) , but I just wanted to point out that Python has a number of really excellent tools for parallel computing/splitting up work across multiple cores. Here's a short and by no means comprehensive list:
IPython Parallel toolkit: http://ipython.org/ipython-doc/dev/parallel/index.html
mpi4py: https://code.google.com/p/mpi4py
The multiprocessing module in the standard library: http://docs.python.org/library/multiprocessing.html
pyzmq: http://zeromq.github.com/pyzmq/ (what the IPython parallel toolkit is based on)
parallel python (pp): http://www.parallelpython.com/
Cython's wrapping of openmp: http://docs.cython.org/src/userguide/parallelism.html
You will also probably find cython to be much to be a vastly superior tool compared to what Matlab has to offer if you ever need to interface external C-libraries or write C-extensions, and it has excellent numpy support built right in.
There is a list with a bunch of other options here:
http://wiki.python.org/moin/ParallelProcessing