doc2vec | document similarity based on gensim doc2vec | Topic Modeling library

Without seeing your training code, there could easily be errors in text prep & training. Many online code examples are bonkers wrong in their Doc2Vec training technique!

Note that min_count=1 is essentially always a bad idea with this sort of algorithm: any example suggesting that was likely from a misguided author.

Is a mere .split() also the only tokenization applied for training? (The inference list-of-tokens should be prepped the same as the training lists-of-tokens.)

How was "not very good" and "oddly even worse" evaluated? For example, did the results seem arbitrary, or in-the-right-direction-but-just-weak?

"8,000 small documents" is a bit on the thin side for a training corpus, but it somewhat depends on "how small" – a few words, a sentence, a few sentences? Moving to smaller vectors, or more training epochs, can sometimes make the best of a smallish training set - but this sort of algorithm works best with lots of data, such that dense 100d-or-more vectors can be trained.

If I understood your problem correctly one possible solution within the tidyverse is to make the data long, remove the leading letters from Title and Header, split them on the dot and filter by comparing the results. Finally a new column is generated to serve as column names after this the data is made wide again:

Similar to model.corpus_count, the tally of words from the last corpus provided to .build_vocab() should be cached in the model as model.corpus_total_words.

Where did the file patent_doc2v_10e.model come from?

If trying to load that file, it generates such an error about another file with the name patent_doc2v_10e.model.trainables.syn1neg.npy, then that other file is a necessary part of the full model that should have been created alongside patent_doc2v_10e.model when that patent_doc2v_10e.model file was first .save()-persisted to disk.

You'll need to go back to where patent_doc2v_10e.model was created, & find the extra missing patent_doc2v_10e.model.trainables.syn1neg.npy file (& possibly others also starting patent_doc2v_10e.model…). All such files created at the same .save() must be kept/moved together, at the same filesystem path, for any future .load() to succeed.

(Additionally, if you are training these yourself from original data, I'd suggest being sure to use a current version of Gensim. Only older pre-4.0 versions will create any save files with trainables in the name.)

If the your gold standard of what the model should report is skills that appeared in the training data, are you sure you don't want a simple count-based solution? For example, just provide a ranked list of the skills that appear most often in Director Of Commercial Operations listings?

On the other hand, the essence of compressing N job titles, and 30,000 skills, into a smaller (in this case vector_size=80) coordinate-space model is to force some non-intuitive (but perhaps real) relationships to be reflected in the model.

Might there be some real pattern in the model – even if, perhaps, just some idiosyncracies in the appearance of less-common skills – that makes aeration necessarily slot near those other skills? (Maybe it's a rare skill whose few contextual appearances co-occur with other skills very much near 'capacity utilization' -meaning with the tiny amount of data available, & tiny amount of overall attention given to this skill, there's no better place for it.)

Taking note of whether your 'anomalies' are often in low-frequency skills, or lower-freqeuncy job-ids, might enable a closer look at the data causes, or some disclaimering/filtering of most_similar() results. (The most_similar() method can limit its returned rankings to the more frequent range of the known vocabulary, for cases when the long-tail or rare words are, in with their rougher vectors, intruding in higher-quality results from better-reqpresented words. See the restrict_vocab parameter.)

That said, tinkering with training parameters may result in rankings that better reflect your intent. A larger min_count might remove more tokens that, lacking sufficient varied examples, mostly just inject noise into the rest of training. A different vector_size, smaller or larger, might better capture the relationships you're looking for. A more-aggressive (smaller) sample could discard more high-frequency words that might be starving more-interesting less-frequent words of a chance to influence the model.

Note that with dbow_words=1 & a large window, and records with (perhaps?) dozens of skills each, the words are having a much-more neighborly effect on each other, in the model, than the tag<->word correlations. That might be good or bad.

Generally due to threading-contention inherent to both the Python 'Global Interpreter Lock' ('GIL'), and the default Gensim master-reader-thread, many-worker-thread approach, the training can't keep all cores mostly-busy with separate threads, once you get past about 8-16 cores.

If you can accept that the only tag for each text will be its ordinal number in the corpus, the alternate corpus_file method of specifying the training-data allow arbitrarily many threads to each open their own readers into the (whitespace-token-delimited) plain-text corpus file, achieving much higher core utilization when you have 16+ cores/workers.

See the Gensim docs for the corpus_file parameter:

https://radimrehurek.com/gensim/models/doc2vec.html#gensim.models.doc2vec.Doc2Vec

Note though there are some unsolved bugs that hint this mode might mishandle or miss training data at some segmentation boundaries. (This may not be significant in large training data.)

Otherwise, other tweaks to parameters that help Word2Vec/Doc2Vec training run faster may be worth trying, such as altered window, vector_size, negative values. (Though note that counterintuitively, when the bottleneck is thread-contention in Gensim's default corpus-iterable mode, some values in these parameters that normally require more computation and thus imply slower training manage to mainly soak up previously-idle contention time, and thus are comparitively 'free'. So when suffering contention, trying more-expensive values for window/negative/vector_size may become more practical.)

Generally, a higher min_count (discarding more rare words), or a more-aggressive (smaller) sample value (discarding more of the overrepresented high-frequency words), can also reduce the amount of raw training happening and thus finish training faster, with minimal effect on quality. (Sometimes, more-aggressive sample values manage to both speed training & improve results on downstream evaluations, by letting the model spend relatively more time on rarer words that are still important downstream.)

While not quite able to "choose the best (all or nothing) transformer subset of features", we can use scikit's feature selection or dimensionality reduction modules to "choose/simplify the best feature subset across ALL transformers" as an extra step before classification:

As a beginner, only vector_size will be of initial interest.

Typical values are 100-1000, but larger dimensionalities require far more training data & more memory. There's no hard & fast rules – try different values, & see what works for your purposes.

Very vaguely, you'll want your count of unique vocabulary words to be much larger than the vector_size, at least the square of the vector_size: the gist of the algorithm is to force many words into a smaller-number of dimensions. (If for some reason you're running experiments on tiny amounts of data with a tiny vocabulary – for which word2vec isn't really good anyway – you'll have to shrink the vector_size very low.)

The negative value controls a detail of how the internal neural network is adjusted: how many random 'noise' words the network is tuned away from predicting for each target positive word it's tuned towards predicting. The default of 5 is good unless/until you have a repeatable way to rigorously score other values against it.

Similarly, sample controls how much (if at all) more-frquent words are sometimes randomly skipped (down-sampled). (So many redundant usage examples are overkill, wasting training time/effort that could better be spent on rarer words.) Again, you'd only want to tinker with this if you've got a way to compare the results of alternate values. Smaller values make the downsampling more aggressive (dropping more words). sample=0 would turn off such down-sampling completely, leaving all training text words used.

Though you didn't ask:

dm=0 turns off the default PV-DM mode in favor of the PV-DBOW mode. That will train doc-vectors a bit faster, and often works very well on short texts, but won't train word-vectors at all (unless you turn on an extra dbow_words=1 mode to add-back interleaved ski-gram word-vector training).

hs is an alternate mode to train the neural-network that uses multi-node encodings of words, rather than one node per (positive or negative) word. If enabled via hs=1, you should disable the negative-sampling with negative=0. But negative-sampling mode is the default for a reason, & tends to get relatively better with larger amounts of training data - so it's rare to use this mode.

If your corpus might have some major difference-in-character between early & late documents – such as certain words/topics that are all front-loaded to early docs, or all back-loaded in later docs – then performing one shuffle up-front to eliminate any such pattern may help a little. It's not strictly necessary & its effects on end results will likely be small.

Re-shuffling between every training pass is not common & I wouldn't expect it to offer a detectable benefit justifying its cost/code-complexity.

Regarding your "Option 1" vs "Option 2": Don't call train() multiple times in your own loop unless you're an expert who knows exactly why you're doing that. (And: any online example suggesting that is often a poor/buggy one.)