PPO Update Schedule in OpenAi Baselines Implementations - machine-learning

I'm trying to read through the PPO1 code in OpenAi's Baselines implementation of RL algorithms (https://github.com/openai/baselines) to gain a better understanding as to how PPO works, how one might go about implementing it, etc.
I'm confused as to the difference between the "optim_batchsize" and the "timesteps_per_actorbatch" arguments that are fed into the "learn()" function. What are these hyper-parameters?
In addition, I see in the "run_atari.py" file, the "make_atari" and "wrap_deepmind" functions are used to wrap the environment. In the "make_atari" function, it uses the "EpisodicLifeEnv", which ends the episode once the a life is lost. On average, I see that the episode length in the beginning of training is about 7 - 8 timesteps, but the batch size is 256, so I don't see how any updates can occur. Thanks in advance for your help.

I've been going through it on my own as well....their code is a nightmare!
optim_batchsize is the batch size used for optimizing the policy, timesteps_per_actorbatch is the number of time steps the agent runs before optimizing.
On the episodic thing, I am not sure. Two ways it could happen, one is waiting until the 256 entries are filled before actually updating, or the other one is filling the batch with dummy data that does nothing, effectively only updating the 7 or 8 steps that the episode lasted.

Related

Build vocab in doc2vec

I have a list of abstracts and articles approx 500 in csv each paragraph contains approx 800 to 1000 words whenever I build vocab and print with words giving none and how I can improve results?
lst_doc = doc.translate(str.maketrans('', '', string.punctuation))
target_data = word_tokenize(lst_doc)
train_data = list(read_data())
model = gensim.models.doc2vec.Doc2Vec(vector_size=50, min_count=2, epochs=40)
train_vocab = model.build_vocab(train_data)
print(train_vocab)
{train = model.train(train_data, total_examples=model.corpus_count,
epochs=model.epochs) }
Output:
None
A call to build_vocab() only builds the vocabulary inside the model, for further usage. That function call doesn't return anything, so your train_vocab variable will be Python None.
So, the behavior you're seeing is as expected, and you should say more about what your ultimate aims are, and what you'd want to see as steps towards those aims, if you're stuck.
If you want to see reporting of the progress of your calls to build_vocab() or train(), you can set the logging level to INFO. This is always a usually a good idea working to learn a new library: even if initially the copious info shown is hard to understand, by reviewing it you'll start to see the various internal steps, and internal counts/timings/etc, that hint whehter things are doing well or poorly.
You can also examine the state of the model and its various internal properties after the code has run.
For example, the model.wv property contains, after build_vocab(), a Gensim KeyedVectors structure holding all the untrained ready-for-training vectors. You can ask for its length (len(model.wv) or examine the discovered active list of words (model.wv.index_to_key).
Other comments:
It's not clear your 1st two lines – assigning into lst_doc and target_data – affect anything further, since it's unclear what read_data() might be doing to fill the train_corpus.
Often low min_count values worsen results, by including more words that have so few usage examples that they're little more than noise during training.
only 500 documents is rather small compared to most published work showing impressive results with this algorithm, which uses tens-of-thousands of documents (if not millions). So, keep in mind that results on such a small dataset may be unrepresentative of what's possible with a larger corpus - in terms of quality, optimal parameters, etc.

Apache-camel Xpathbuilder performance

I have following question. I set up an camel -project to parse certain xml files. I have to selecting take out certain nodes from a file.
I have two files 246kb and 347kb in size. I am extracting a parent-child pair of 250 nodes in the above given example.
With the default factory here are the times. For the 246kb file respt 77secs and 106 secs. I wanted to improve the performance so switched to saxon and the times are as follows 47secs and 54secs. I was able to cut the time down by at least half.
Is it possible to cut the time further, any other factory or optimizations I can use will be appreciated.
I am using XpathBuilder to cut the xpaths out. here is an example. Is it possible to not to have to create XpathBuilder repeatedly, it seems like it has to be constructed for every xpath, I would have one instance and keep pumping the xpaths into it, maybe it will improve performance further.
return XPathBuilder.xpath(nodeXpath)
.saxon()
.namespace(Consts.XPATH_PREFIX, nameSpace)
.evaluate(exchange.getContext(), exchange.getIn().getBody(String.class), String.class);
Adding more details based on Michael's comments. So I am kind of joining them, will become clear with my example below. I am combining them into a json.
So here we go, Lets say we have following mappings for first and second path.
pData.tinf.rexd: bm:Document/bm:xxxxx/bm:PmtInf[{0}]/bm:ReqdExctnDt/text()
pData.tinf.pIdentifi.instId://bm:Document/bm:xxxxx/bm:PmtInf[{0}]/bm:CdtTrfTxInf[{1}]/bm:PmtId/bm:InstrId/text()
This would result in a json as below
pData:{
tinf: {
rexd: <value_from_xml>
}
pIdentifi:{
instId: <value_from_xml>
}
}
Hard to say without seeing your actual XPath expression, but given the file sizes and execution time my guess would be that you're doing a join which is being executed naively as a cartesian product, i.e. with O(n*m) performance. There is probably some way of reorganizing it to have logarithmic performance, but the devil is in the detail. Saxon-EE is quite good at optimizing join queries automatically; if not, there are often ways of doing it manually -- though XSLT gives you more options (e.g. using xsl:key or xsl:merge) than XPath does.
Actually I was able to bring the time down to 10 secs. I am using apache-camel. So I added threads there so that multiple files can be read in separate threads. Once the file was being read, it had serial operation to based on the length of the nodes that had to be traversed. I realized that it was not necessary to be serial here so introduced parrallelStream and that now gave it enough power. One thing to guard agains is not to have a proliferation of threads since that can degrade the performance. So I try to restrict the number of threads to twice or thrice the number of cores on the operating machine.

Google Dataflow spending hours estimating input size

I'm fairly new to Google Dataflow and I am finding that the service spends several hours estimating the input file size before actually processing data, and will often do several recounts for large input collections before failing. I'm using Apache Beam 2.9 and the io.ReadFromText method.
The logs start with a comment about beginning estimation of input file size and continue to log an update every 10k files counted.
Is there a way to skip this step or to significantly increase the pace in which it does the count?
The Python ReadFromText source is based on FileBasedSource. If you look at the code for it, you can find that its estimate_size method is inefficient for a very large set of files.
As we discussed in the comments, you may be able to improve this bottleneck by manually partitioning the range of files. For example, if your files are gs://my_bucket/file001, gs://my_bucket/file002, ... gs://my_bucket/file999, you should be able to add 10 sources, something like so:
p = Pipeline()
file_lines = (
[p | ReadFromText('gs://my_bucket/file%s*' % i) for i in range(10)]
| beam.Flatten())
This should help your pipeline scale for a case like this.
As for a permanent solution... I imagine that one could try to propose improvements to the source itself, so that a future version may have better performance.
There are also transforms based on Java's FileIO transforms that we are planning to implement. That may be helpful as well. But it's not so near in the horizon.

Dynamic Process parameter adjustment in Semiconductor manufacturing data

I have process parameter data from semiconductor manufacturing.and requirement is to suggest what could be the best parameter adjustment to be made to process parameter to get better yield ie best path for high yield. what machine learning /Statistical models best suits this requirement
Note:I have thought of using decision tree which can give us best path for high yield.
Would like to know it any other methods that can be more efficient
data is like
lotno x1 x2 x3 x4 x5 yield(%)
<95% yield is considered as 0 and >95% as 1
I'm not really sure of the question here, but as a former semiconductor process engineer, here is how I look at the yield improvement approach - perspective.
Process Development.
DOE: Typically, I would run structured DOEs to understand my process (#4). I would first identify "potential" 'factors', and run various "screening" experiments to identify statistical significance. With the goal basically here to identify the most statistically significant (and for that matter, least significant) factors. So these are inherently simple experiments, low # of "levels" which don't target understanding of the curvature of the response surface, they just look for magnitude change of response vs factor. Generally, I am most concerned with 'Process' factors, but it is important to recognize that the influence of variable inputs can come from more than just "machine knobs' as example. Variable can arise from 1) People, 2) Environment (moisture, temp, etc), 3) consumables (used in the process), 4) Equipment (is 40 psi on this tool really 40 psi and the same as 40 psi on a different tool) 4) Process variable settings.
With the most statistically significant factors, I would run more elaborate DOE using the major factors and analyze this data to develop a model. There are generally more 'levels' used here to allow for curvature insight of the response surface via the analysis. There are many types of well known standard experimental design structures here. And there is software such as JMP that is specifically set up to do this analysis.
From here, the idea would be to generate a model in the form of Response = F (Factors). That allows you to essentially optimize the response based upon these factors where the response is a reflection of your yield criteria.
From here, the engineer would typically execute confirmation runs with optimized factors to confirm optimized response.
Note that the software analysis typically allows for the engineer to illuminate any run order dependence. The execution of the DOE is typically performed in a randomized cell fashion. (Each 'cell' is a set of conditions for the experiment). Similarly the experiments include some level of repetition to gauge 'repeatability' of the 'system'. This inclusion can be explicit (run the same cell twice), but there is also some level of repeatability inherent in the design as well since you are running multiple cells, albeit at difference settings. But generally, the experiment includes explicitly repeated cells.
And finally there is the concept of manufacturability, which includes constraints of time, cost, physical limits, equipment capability, etc. (The ideal process works great, but it takes 10 years, costs 1 million dollars and requires projected settings outsides the capability of the tool.)
Since you have manufacturing data, hopefully, you have the data that captures the other types of factors as well (1,2,3), so you should specifically analyze the data to try to identify such effects. This is typically done as A vs B comparisons. Person A vs B, Tool A vs B, Consumable A vs B, Consumable lot A vs B, Summer vs Winter, etc.
Basically, there are all sorts of comparisons you could envision here and check for statistically differences across two sets of populations.
A comment on response: What is the yield criteria? You should know this in order to formulate the model. For semiconductors, we have both line yield (process yield) but there is also device yield. I assume for your work, you are primarily concerned with line yield. So minimizing variability in the factors (from 1,2,3,4) to achieve the desired response (target response(s) with minimal variability) is the primary goal.
APC (Advanced Process Control).
In many cases, there is significant trending that results from whatever reason; crappy tool control (the tool heats up), crappy consumable (the target material wears, the polishing pad wears, the chemical bath gets loaded, whatever), and so the idea here is how to adjust the next batch/lot/wafer based upon the history of what came prior. Either improve the manufacturing to avoid/minimize this trending (run order dependence) or adjust process to accommodate it to achieve the desired response.
Time for lunch, hope this helps...if you post on the specific process module type, and even equipment and consumables, I might be able to provide more insight.

If I called arc4random_uniform(6) at 5 o'clock OR 5:01, would I get the same number?

I'm making an iOS dice game and one beta tester said he liked the idea that the rolls were already predetermined, as I use arc4random_uniform(6). I'm not sure if they are. So leaving aside the possibility that the code may choose the same number consecutively, would I generate a different number if I tapped the dice in 5 or 10 seconds time?
Your tester was probably thinking of the idea that software random number generators are in fact pseudo-random. Their output is not truly random as a physical process like a die roll would be: it's determined by some state that the generators hold or are given.
One simple implementation of a PRNG is a "linear congruential generator": the function rand() in the standard library uses this technique. At its core, it is a straightforward mathematical function, and each output is generated by feeding in the previous one as input. It thus takes a "seed" value, and -- this is what your tester was thinking of -- the sequence of output values that you get is completely determined by the seed value.
If you create a simple C program using rand(), you can (must, in fact) use the companion function srand() (that's "seed rand") to give the LCG a starting value. If you use a constant as the seed value: srand(4), you will get the same values from rand(), in the same order, every time.
One common way to get an arbitrary -- note, not random -- seed for rand() is to use the current time: srand(time(NULL)). If you did that, and re-seeded and generated a number fast enough that the return of time() did not change, you would indeed see the same output from rand().
This doesn't apply to arc4random(): it does not use an LCG, and it does not share this trait with rand(). It was considered* "cryptographically secure"; that is, its output is indistinguishable from true, physical randomness.
This is partly due to the fact that arc4random() re-seeds itself as you use it, and the seeding is itself based on unpredictable data gathered by the OS. The state that determines the output is entirely internal to the algorithm; as a normal user (i.e., not an attacker) you don't view, set, or otherwise interact with that state.
So no, the output of arc4random() is not reliably repeatable by you. Pseudo-random algorithms which are repeatable do exist, however, and you can certainly use them for testing.
*Wikipedia notes that weaknesses have been found in the last few years, and that it may no longer be usable for cryptography. Should be fine for your game, though, as long as there's no money at stake!
Basically, it's random. No it is not based around time. Apple has documented how this is randomized here: https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/arc4random_uniform.3.html

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