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diff --git a/2024/captions/emacsconf-2024-p-search--psearch-a-local-search-engine-in-emacs--zac-romero--main.vtt b/2024/captions/emacsconf-2024-p-search--psearch-a-local-search-engine-in-emacs--zac-romero--main.vtt new file mode 100644 index 00000000..111f2728 --- /dev/null +++ b/2024/captions/emacsconf-2024-p-search--psearch-a-local-search-engine-in-emacs--zac-romero--main.vtt @@ -0,0 +1,970 @@ +WEBVTT captioned by sachac + +NOTE Search in daily workflows + +00:00:00.000 --> 00:00:03.399 +Hello, my name is Zachary Romero, and today I'll be going + +00:00:03.400 --> 00:00:08.115 +over p-search, a local search engine in Emacs. + +00:00:08.116 --> 00:00:12.398 +Search these days is everywhere in software, from text editors, + +00:00:12.399 --> 00:00:18.359 +to IDEs, to most online websites. These tools tend to fall + +00:00:18.360 --> 00:00:25.839 +into one of two categories. One are tools that run locally, + +00:00:25.840 --> 00:00:31.279 +and work by matching string to text. The most common + +00:00:31.280 --> 00:00:35.639 +example of this is grep. In Emacs, there are a lot of + +00:00:35.640 --> 00:00:38.959 +extensions which provide functionality on top of these + +00:00:38.960 --> 00:00:42.388 +tools, such as projectile-grep, deadgrep, + +00:00:42.389 --> 00:00:46.849 +consult-ripgrep. Most editors have some sort of + +00:00:46.850 --> 00:00:52.691 +search current project feature. Most of the time, + +00:00:52.692 --> 00:00:56.393 +some of these tools have features like regular expressions, + +00:00:56.394 --> 00:00:59.215 +or you can specify file extension, + +00:00:59.216 --> 00:01:01.636 +or a directory you want to search in, + +00:01:01.637 --> 00:01:03.957 +but features are pretty limited. + +00:01:03.958 --> 00:01:07.919 +The other kind of search we use are usually hosted online, + +00:01:07.920 --> 00:01:12.302 +and they usually search a vast corpus of data. + +00:01:12.303 --> 00:01:15.639 +These are usually proprietary + +00:01:15.640 --> 00:01:18.765 +online services such as Google, GitHub, + +00:01:18.766 --> 00:01:24.199 +SourceGraph for code. + +NOTE Problems with editor search tools + +00:01:24.200 --> 00:01:28.839 +The kind of search feature that editors + +00:01:28.840 --> 00:01:36.719 +usually have have a lot of downsides to them. For one, a lot + +00:01:36.720 --> 00:01:38.839 +of times you don't know the exact search string you're + +00:01:38.840 --> 00:01:42.783 +searching for. Some complicated term like this + +00:01:42.784 --> 00:01:46.860 +high volume demand partner, you know, do you know if... + +00:01:46.861 --> 00:01:49.708 +Are some words abbreviated, is it capitalized, + +00:01:49.709 --> 00:01:53.089 +is it in kebab case, camel case, snake case? + +00:01:53.090 --> 00:01:57.571 +You often have to search all these variations. + +00:01:57.572 --> 00:02:05.434 +Another downside is that the search results returned + +00:02:05.435 --> 00:02:07.769 +contain a lot of noise. For example, + +00:02:07.770 --> 00:02:10.816 +you may get a lot of test files. + +00:02:10.817 --> 00:02:13.537 +If the tool hits your vendor directory, + +00:02:13.538 --> 00:02:17.199 +it may get a bunch of results from libraries + +00:02:17.200 --> 00:02:22.879 +you're using, which most are not helpful. Another downside + +00:02:22.880 --> 00:02:26.679 +is that the order given is, well, there's no meaning to the + +00:02:26.680 --> 00:02:30.319 +order. It's usually just the search order that the tool + +00:02:30.320 --> 00:02:34.639 +happens to look in first. + +00:02:34.640 --> 00:02:38.639 +Another thing is, so when you're searching, you oftentimes + +00:02:38.640 --> 00:02:41.639 +have to keep the state of the searches in your head. For + +00:02:41.640 --> 00:02:46.639 +example, you try one search, you see the results, find the + +00:02:46.640 --> 00:02:49.639 +results you think are relevant, keep them in your head, run + +00:02:49.640 --> 00:02:52.519 +search number two, look through the results, kind of + +00:02:52.520 --> 00:02:56.119 +combine these different search results in your head until + +00:02:56.120 --> 00:02:59.970 +you get an idea of which ones might be relevant. + +00:02:59.971 --> 00:03:04.515 +Another thing is that the search primitives are fairly limited. + +00:03:04.516 --> 00:03:10.599 +So yeah, you can search regular expressions, but you can't + +00:03:10.600 --> 00:03:14.719 +really define complex things like, I want to search files in + +00:03:14.720 --> 00:03:18.439 +this directory, and this directory, and this directory, + +00:03:18.440 --> 00:03:22.319 +except these subdirectories, and accept test files, and I + +00:03:22.320 --> 00:03:25.559 +only want files with this file extension. Criteria like + +00:03:25.560 --> 00:03:28.919 +that are really hard to... I'm sure they're possible in tools + +00:03:28.920 --> 00:03:34.479 +like grep, but they're pretty hard to construct. + +00:03:34.480 --> 00:03:38.199 +And lastly, there's no notion of any relevance. All the + +00:03:38.200 --> 00:03:42.039 +results you get back, I mean, you don't know, is the search + +00:03:42.040 --> 00:03:43.095 +more relevant? Is it twice as relevant? Is it + +00:03:43.096 --> 00:03:52.279 +100 times more relevant? These tools usually don't provide + +00:03:52.280 --> 00:03:58.232 +such information. + +NOTE Information retrieval + +00:03:58.233 --> 00:04:00.394 +There's a field called information retrieval, + +00:04:00.395 --> 00:04:02.616 +and this deals with this exact problem. + +00:04:02.617 --> 00:04:04.718 +You have lots of data you're searching for. + +00:04:04.719 --> 00:04:09.261 +How do you construct a search query? + +00:04:09.262 --> 00:04:09.839 +How do you get results back fast? How do you + +00:04:09.840 --> 00:04:14.519 +rank which ones are most relevant? How do you evaluate + +00:04:14.520 --> 00:04:20.079 +your search system to see if it's getting better or worse? + +00:04:20.080 --> 00:04:23.119 +There's a lot of work, a lot of books written on the topic of + +00:04:23.120 --> 00:04:28.159 +information retrieval. If one wants to improve + +00:04:28.160 --> 00:04:31.879 +searching in Emacs, then drawing inspiration from this + +00:04:31.880 --> 00:04:34.295 +field is necessary. + +NOTE Search engine in Emacs: the index + +00:04:34.296 --> 00:04:41.383 +The first aspect of information retrieval is the index. + +00:04:41.384 --> 00:04:46.608 +The reverse index is what search engines use to find results really fast. + +00:04:46.609 --> 00:04:51.454 +Essentially, it's a map of search term + +00:04:51.455 --> 00:04:54.738 +to locations where that term is located. + +00:04:54.739 --> 00:04:57.079 +You'll have all the terms or maybe even parts of + +00:04:57.080 --> 00:04:59.159 +the terms, and then you'll have all the locations where + +00:04:59.160 --> 00:05:02.119 +they're located. Any query could easily look up + +00:05:02.120 --> 00:05:05.919 +where things are located, join results together, and + +00:05:05.920 --> 00:05:12.879 +that's how they get the results to be really fast. For this + +00:05:12.880 --> 00:05:19.159 +project, I decided to forgo creating an index altogether. + +00:05:19.160 --> 00:05:23.759 +An index is pretty complicated to maintain because + +00:05:23.760 --> 00:05:27.319 +it always has to be in sync. Any time you open a file and save + +00:05:27.320 --> 00:05:29.959 +it, you would have to re-index, you would have to make sure + +00:05:29.960 --> 00:05:32.559 +that file is re-indexed properly. Then you have the + +00:05:32.560 --> 00:05:36.119 +whole issue of, well, if you're searching in Emacs, + +00:05:36.120 --> 00:05:38.799 +you have all these projects, this directory, + +00:05:38.800 --> 00:05:42.479 +that directory, how do you know which? Do you always have to + +00:05:42.480 --> 00:05:47.399 +keep them in sync? It's quite a hard task to handle + +00:05:47.400 --> 00:05:53.079 +that. Then on the other end, tools like ripgrep can + +00:05:53.080 --> 00:05:59.119 +search very fast. Even though they can't search maybe on the + +00:05:59.120 --> 00:06:03.919 +order of tens of thousands of repositories, for a local + +00:06:03.920 --> 00:06:06.039 +setting, they should be plenty fast enough. + +00:06:06.040 --> 00:06:12.239 +I benchmarked. Ripgrep, for example, is + +00:06:12.240 --> 00:06:15.959 +on the order of gigabytes per second. + +00:06:15.960 --> 00:06:19.239 +Definitely, it can search a few pretty big size + +00:06:19.240 --> 00:06:21.756 +repositories. + +NOTE Search engine in Emacs: Ranking + +00:06:21.757 --> 00:06:24.799 +Next main task. We decided not to use an + +00:06:24.800 --> 00:06:29.959 +index. Next task is how do we rank search results? So there's + +00:06:29.960 --> 00:06:33.439 +two main algorithms that are used these days. The first + +00:06:33.440 --> 00:06:36.519 +one is tf-idf, which stands for term frequency, inverse + +00:06:36.520 --> 00:06:43.039 +target frequency. Then there's BM25, which is sort of a + +00:06:43.040 --> 00:06:43.552 +modified tf-idf algorithm. + +NOTE tf-idf: term-frequency x inverse-document-frequency + +00:06:43.553 --> 00:06:45.679 +tf-idf, without going into + +00:06:45.680 --> 00:06:49.159 +too much detail, essentially multiplies two terms. One + +00:06:49.160 --> 00:06:51.879 +is the term frequency, and then you multiply it by the + +00:06:51.880 --> 00:06:54.559 +inverse document frequency. The term frequency is a + +00:06:54.560 --> 00:06:58.519 +measure of how often that search term occurs. The + +00:06:58.520 --> 00:07:00.799 +inverse document frequency is a measure of how much + +00:07:00.800 --> 00:07:06.199 +information that term provides. If the term occurs a lot, + +00:07:06.200 --> 00:07:08.719 +then it gets a higher score in the term frequency section. + +00:07:08.720 --> 00:07:12.399 +But if it's a common word that exists in a lot of documents, + +00:07:12.400 --> 00:07:13.900 +then its inverse document frequency goes down. + +00:07:13.901 --> 00:07:20.879 +It kind of scores it less. You'll find that words like the, + +00:07:20.880 --> 00:07:25.959 +in, is, these really common words, since they occur + +00:07:25.960 --> 00:07:29.199 +everywhere, their inverse document frequency is + +00:07:29.200 --> 00:07:32.479 +essentially zero. They don't really count towards a + +00:07:32.480 --> 00:07:35.679 +score. But when you have rare words that only occur in a + +00:07:35.680 --> 00:07:37.679 +few documents, they're weighted a lot more. So the more + +00:07:37.680 --> 00:07:41.159 +those rare words occur, they boost the score higher. + +NOTE BM25 + +00:07:41.160 --> 00:07:48.839 +BM25 is a modification of this. It's essentially TF, it's + +00:07:48.840 --> 00:07:53.119 +essentially the previous one, except it dampens out terms + +00:07:53.120 --> 00:07:55.439 +that occur more often. Imagine you have a bunch of + +00:07:55.440 --> 00:07:59.359 +documents. One has a term 10 times, one has a term, that same + +00:07:59.360 --> 00:08:02.439 +term a hundred times, another has a thousand times. + +00:08:02.440 --> 00:08:06.799 +You'll see the score dampens off as the number of + +00:08:06.800 --> 00:08:10.639 +occurrences increases. That prevents any one term from + +00:08:10.640 --> 00:08:16.559 +overpowering the score. This is the algorithm I ended up + +00:08:16.560 --> 00:08:21.039 +choosing for my implementation. So with a plan of using a + +00:08:21.040 --> 00:08:29.559 +command line tool like ripgrep to get term occurrences, and + +00:08:29.560 --> 00:08:36.799 +then using a scoring algorithm like BM25 to rank the terms, + +00:08:36.800 --> 00:08:40.079 +we can combine this together and create a simple search + +00:08:40.080 --> 00:08:41.199 +mechanism. + +NOTE Searching with p-search + +00:08:41.200 --> 00:08:47.439 +Here we're in the directory for the Emacs source code. + +00:08:47.440 --> 00:08:53.479 +Let's say we want to search for the display code. We + +00:08:53.480 --> 00:08:58.679 +run the p-search command, starting the search engine. It + +00:08:58.680 --> 00:09:01.159 +opens up. We notice it has three sections, the candidate + +00:09:01.160 --> 00:09:05.199 +generators, the priors, and the search results. The + +00:09:05.200 --> 00:09:09.999 +candidate generators generates the search space we're + +00:09:10.000 --> 00:09:14.719 +looking on. These are all composable and you can add as + +00:09:14.720 --> 00:09:19.719 +many as you want. So with this, it specifies that here + +00:09:19.720 --> 00:09:25.239 +we're searching on the file system and we're searching in + +00:09:25.240 --> 00:09:30.799 +this directory. We're using the ripgrep tool to search + +00:09:30.800 --> 00:09:33.359 +with, and we want to make sure that we're searching only on + +00:09:33.360 --> 00:09:40.479 +files committed to Git. Here we see the search results. + +00:09:40.480 --> 00:09:45.159 +Notice here is their final probability. Here, notice + +00:09:45.160 --> 00:09:47.079 +that they're all the same, and they're the same because we + +00:09:47.080 --> 00:09:50.719 +don't have any search criteria specified here. Suppose + +00:09:50.720 --> 00:09:55.679 +we want to search for display-related code. We add a + +00:09:55.680 --> 00:09:57.359 +query: display. + +00:09:57.360 --> 00:10:06.559 +So then it spins off the processes, gets the search term + +00:10:06.560 --> 00:10:10.879 +counts and calculates the new scores. Notice here that + +00:10:10.880 --> 00:10:15.759 +the results that come on top are just at first glance appear + +00:10:15.760 --> 00:10:19.919 +to be relevant to display. Remember, if we compare + +00:10:19.920 --> 00:10:25.079 +that to just running a ripgrep raw, notice here we're + +00:10:25.080 --> 00:10:31.279 +getting 53,000 results and it's pretty hard to go through + +00:10:31.280 --> 00:10:34.319 +these results and make sense of it. + +00:10:34.320 --> 00:10:41.456 +So that's p-search in a nutshell. + +NOTE Flight AF 447 + +00:10:41.457 --> 00:10:45.982 +Next, I wanted to talk about the story of Flight 447. + +00:10:45.983 --> 00:10:49.326 +Flight 447 going from Rio de Janeiro to Paris + +00:10:49.327 --> 00:10:51.509 +crashed somewhere in the Atlantic Ocean + +00:10:51.510 --> 00:10:54.713 +on June 1st, 2009, killing everyone on board. + +00:10:54.714 --> 00:10:56.894 +Four search attempts were made to find the wreckage. + +00:10:56.895 --> 00:11:01.075 +None of them were successful, except the finding of some debris + +00:11:01.076 --> 00:11:05.479 +and a dead body. It was decided that they really wanted + +00:11:05.480 --> 00:11:09.519 +to find the wreckage to retrieve data as to why the search + +00:11:09.520 --> 00:11:14.639 +occurred. This occurred two years after the + +00:11:14.640 --> 00:11:19.959 +initial crash. With this next search attempt, they + +00:11:19.960 --> 00:11:23.199 +wanted to create a probability distribution of where the + +00:11:23.200 --> 00:11:26.759 +crash could be. The only piece of concrete data they had + +00:11:26.760 --> 00:11:35.079 +was a GPS signal from the ship at 210 containing the GPS + +00:11:35.080 --> 00:11:40.239 +location of the plane was at 2.98 degrees north, 30.59 + +00:11:40.240 --> 00:11:44.719 +degrees west. That was the only data they had to go off of. + +00:11:44.720 --> 00:11:50.079 +So they drew a circle around that point + +00:11:50.080 --> 00:11:54.679 +with a radius of 40 nautical miles. They assumed that + +00:11:54.680 --> 00:11:57.479 +anything outside the circle would have been impossible for + +00:11:57.480 --> 00:12:01.239 +the ship to reach. This was the starting point for + +00:12:01.240 --> 00:12:04.799 +creating the probability distribution of where the + +00:12:04.800 --> 00:12:08.119 +wreckage occurred. Anything outside the circle, they + +00:12:08.120 --> 00:12:09.639 +assumed it was impossible to reach. + +00:12:09.640 --> 00:12:16.479 +The only other pieces of data were the four failed search + +00:12:16.480 --> 00:12:21.719 +attempts and then some of the debris found. One thing they + +00:12:21.720 --> 00:12:26.159 +did decide was to look at similar crashes where control was + +00:12:26.160 --> 00:12:30.319 +lost to analyze where the crashes landed, compared to where + +00:12:30.320 --> 00:12:37.399 +the loss of control started. This probability + +00:12:37.400 --> 00:12:43.479 +distribution, the circular normal distribution was + +00:12:43.480 --> 00:12:47.919 +decided upon. Here you can see that the center has a lot + +00:12:47.920 --> 00:12:51.879 +higher chance of finding the wreckage. As you go away + +00:12:51.880 --> 00:12:55.399 +from the center, the probability of finding the wreckage + +00:12:55.400 --> 00:13:02.319 +decreases a lot. The next thing they looked at was, well, + +00:13:02.320 --> 00:13:05.959 +they noticed they had retrieved some dead bodies from the + +00:13:05.960 --> 00:13:12.959 +wreckage. So they thought that they could calculate the + +00:13:12.960 --> 00:13:18.439 +backward drift on that particular day to find where the + +00:13:18.440 --> 00:13:21.479 +crash might've occurred. If they found bodies at a + +00:13:21.480 --> 00:13:25.119 +particular location, they can kind of work backwards from + +00:13:25.120 --> 00:13:30.665 +that in order to find where the initial crash occurred. + +00:13:30.666 --> 00:13:34.719 +So here you can see the probability distribution based off of + +00:13:34.720 --> 00:13:40.279 +the backward drift model. Here you see the darker colors + +00:13:40.280 --> 00:13:46.159 +have a higher probability of finding the location. So + +00:13:46.160 --> 00:13:50.679 +with all these pieces of data, so with that circular 40 + +00:13:50.680 --> 00:13:54.959 +nautical mile uniform distribution, with that circular + +00:13:54.960 --> 00:14:02.199 +normal distribution of comparing similar crashes, as well + +00:14:02.200 --> 00:14:07.439 +as with the backward drift, they were able to combine all + +00:14:07.440 --> 00:14:08.559 +three of these pieces + +00:14:08.560 --> 00:14:14.599 +in order to come up with a final prior distribution of where + +00:14:14.600 --> 00:14:19.519 +the wreckage occurred. So this is what the final model + +00:14:19.520 --> 00:14:24.719 +they came upon. Here you can see it has that 40 nautical + +00:14:24.720 --> 00:14:29.679 +mile radius circle. It has that darker center, which + +00:14:29.680 --> 00:14:32.039 +indicates a higher probability because of the + +00:14:32.040 --> 00:14:38.959 +crash similarity. Then here you also see along this line + +00:14:38.960 --> 00:14:50.799 +has a slightly higher probability due to the backward drift + +00:14:50.800 --> 00:14:52.119 +distribution. + +00:14:52.120 --> 00:14:56.559 +So the next thing is, since they had performed searches, + +00:14:56.560 --> 00:15:00.559 +they decided to incorporate the data from those searches + +00:15:00.560 --> 00:15:04.759 +into their new distribution. Here you can see places + +00:15:04.760 --> 00:15:08.879 +where they searched initially. If you think about it, + +00:15:08.880 --> 00:15:11.399 +you can assume that, well, if you search for something, + +00:15:11.400 --> 00:15:14.199 +there's a good chance you'll find it, but not necessarily. + +00:15:14.200 --> 00:15:18.439 +Anywhere where they searched, the probability of it + +00:15:18.440 --> 00:15:22.839 +finding it there is greatly reduced. It's not zero because + +00:15:22.840 --> 00:15:26.879 +obviously you can look for something and miss it, but it kind + +00:15:26.880 --> 00:15:31.119 +of reduces the probability that we would expect to find it in + +00:15:31.120 --> 00:15:36.679 +those already searched locations. This is the + +00:15:36.680 --> 00:15:41.919 +posterior distribution or distribution after counting + +00:15:41.920 --> 00:15:44.559 +observations made. + +00:15:44.560 --> 00:15:48.759 +Here we can see kind of these cutouts of where the + +00:15:48.760 --> 00:15:53.959 +previous searches occurred. This is the final + +00:15:53.960 --> 00:15:56.999 +distribution they went off of to perform the subsequent + +00:15:57.000 --> 00:16:01.999 +search. In the end, the wreckage was found at a point close to + +00:16:02.000 --> 00:16:06.770 +the center here, thus validating this methodology. + +NOTE Modifying priors + +00:16:06.771 --> 00:16:10.332 +We can see the power of this Bayesian search methodology + +00:16:10.333 --> 00:16:13.999 +in the way that we could take information from all the sources we had. + +00:16:14.000 --> 00:16:19.237 +We could draw analogies to similar situations. + +00:16:19.238 --> 00:16:22.479 +We can quantify these, combine them into a model, + +00:16:22.480 --> 00:16:27.893 +and then also update our model according to each observation we make. + +00:16:27.894 --> 00:16:30.359 +I think there's a lot of similarities to be drawn with + +00:16:30.360 --> 00:16:35.159 +searching on a computer in the sense that when we search for + +00:16:35.160 --> 00:16:39.399 +something, there's oftentimes a story we kind of have as to + +00:16:39.400 --> 00:16:43.959 +what search terms exist, where we expect to find the file. + +00:16:43.960 --> 00:16:46.719 +For example, if you're implementing a new feature, you'll + +00:16:46.720 --> 00:16:49.919 +often have some search terms in mind that you think will be + +00:16:49.920 --> 00:16:54.719 +relevant. Some search terms, you might think they have a + +00:16:54.720 --> 00:16:57.599 +possibility of being relevant, but maybe you're not sure. + +00:16:57.600 --> 00:17:02.879 +There's some directories where you know that they're not + +00:17:02.880 --> 00:17:07.759 +relevant. There's other criteria like, well, you know that + +00:17:07.760 --> 00:17:11.399 +maybe somebody in particular worked on this code. + +00:17:11.400 --> 00:17:16.319 +What if you could incorporate that information? Like, I know + +00:17:16.320 --> 00:17:21.399 +this author, he's always working on this feature. What if + +00:17:21.400 --> 00:17:25.519 +I just give the files that this person works on a higher + +00:17:25.520 --> 00:17:32.599 +probability than ones he doesn't work on? Or maybe you think + +00:17:32.600 --> 00:17:38.599 +that this is a file that's committed too often. You think + +00:17:38.600 --> 00:17:43.439 +that maybe the amount of times of commits it receives + +00:17:43.440 --> 00:17:47.719 +should change your probability of this file being + +00:17:47.720 --> 00:17:52.839 +relevant. That's where p-search comes in. + +00:17:52.840 --> 00:17:57.679 +Its aim is to be a framework in order to incorporate all these + +00:17:57.680 --> 00:18:01.359 +sorts of different prior information into your searching + +00:18:01.360 --> 00:18:05.999 +process. You're able to say things like, I want files + +00:18:06.000 --> 00:18:11.119 +authored by this user to be given higher probability. I want + +00:18:11.120 --> 00:18:13.919 +this author to be given a lower priority. I know this author + +00:18:13.920 --> 00:18:18.759 +never works on this code. If he has a commit, then lower its + +00:18:18.760 --> 00:18:24.679 +probability, or you can specify specific paths, or you can + +00:18:24.680 --> 00:18:30.199 +specify multiple search terms, weighing different ones + +00:18:30.200 --> 00:18:38.919 +according to how you think those terms should be relevant. + +00:18:38.920 --> 00:18:42.079 +So with p-search, we're able to incorporate information + +00:18:42.080 --> 00:18:46.279 +from multiple sources. Here, for example, we have a prior + +00:18:46.280 --> 00:18:52.079 +of type git author, and we're looking for all of the files + +00:18:52.080 --> 00:18:56.719 +that are committed to by Lars. So the more commits he has, + +00:18:56.720 --> 00:19:01.399 +the higher probability is given to that file. Suppose + +00:19:01.400 --> 00:19:04.559 +there's a feature I know he worked on, but I don't know the + +00:19:04.560 --> 00:19:09.159 +file or necessarily even key terms of it. Well, with this, I + +00:19:09.160 --> 00:19:12.140 +can incorporate that information. + +00:19:12.141 --> 00:19:15.999 +So let's search again. Let's add display. + +00:19:16.000 --> 00:19:22.959 +Let's see what responses we get back here. We can add + +00:19:22.960 --> 00:19:27.199 +as many of these criteria as we want. We can even specify that + +00:19:27.200 --> 00:19:31.519 +the title of the file name should be a certain type. Let's + +00:19:31.520 --> 00:19:36.599 +say we're only concerned about C files. We add the file + +00:19:36.600 --> 00:19:45.399 +name should contain .c in it. With this, now we + +00:19:45.400 --> 00:19:51.319 +notice that all of the C files containing display authored + +00:19:51.320 --> 00:19:56.279 +by Lars should be given higher probability. We can + +00:19:56.280 --> 00:20:02.719 +continue to add these priors as we feel fit. The workflow + +00:20:02.720 --> 00:20:07.519 +that I found helps when searching is that you'll add + +00:20:07.520 --> 00:20:11.359 +criteria, you'll see some good results come up and some bad + +00:20:11.360 --> 00:20:15.319 +results come up. So you'll often find a pattern in those + +00:20:15.320 --> 00:20:18.839 +bad results, like, oh, I don't want test files, or this + +00:20:18.840 --> 00:20:22.679 +directory isn't relevant, or something like that. Then + +00:20:22.680 --> 00:20:27.199 +you can update your prior distribution, adding its + +00:20:27.200 --> 00:20:31.119 +criteria, and then rerun it, and then it will get different + +00:20:31.120 --> 00:20:35.159 +probabilities for the files. So in the end, you'll have a + +00:20:35.160 --> 00:20:37.639 +list of results that's tailor-made to the thing you're + +00:20:37.640 --> 00:20:40.404 +searching for. + +NOTE Importance + +00:20:40.405 --> 00:20:41.639 +There's a couple of other features I + +00:20:41.640 --> 00:20:49.079 +want to go through. One thing is that each of these priors, + +00:20:49.080 --> 00:20:55.839 +you can specify the importance. In other words, how + +00:20:55.840 --> 00:21:01.119 +important is this particular piece of information to your + +00:21:01.120 --> 00:21:05.199 +search? So here, everything is of importance medium. But + +00:21:05.200 --> 00:21:07.879 +let's say I really care about something having the word + +00:21:07.880 --> 00:21:12.679 +display in it. I'm going to change its importance. + +00:21:12.680 --> 00:21:18.599 +Instead of medium, I'll change its importance to high. + +00:21:18.600 --> 00:21:23.279 +What that does essentially is things that don't have + +00:21:23.280 --> 00:21:28.079 +display in it are given a much bigger penalty and things with + +00:21:28.080 --> 00:21:28.128 +the word display in it are rated much higher. + +00:21:28.129 --> 00:21:38.559 +With this, we're able to fine-tune the results that we get. + +NOTE Complement or inverse + +00:21:38.560 --> 00:21:45.639 +Another thing you can do is that you can add the complement or + +00:21:45.640 --> 00:21:49.759 +the inverse of certain queries. Let's say you want to + +00:21:49.760 --> 00:21:53.239 +search for display, but you don't want it to contain the word + +00:21:53.240 --> 00:21:58.039 +frame. With the complement option on, when we create this + +00:21:58.040 --> 00:22:01.839 +search prior, now it's going to be searching for frame, but + +00:22:01.840 --> 00:22:04.959 +instead of increasing the search score, it's going to + +00:22:04.960 --> 00:22:06.999 +decrease it if it contains the word frame. + +00:22:07.000 --> 00:22:14.319 +So here, things related to frame are kind of + +00:22:14.320 --> 00:22:18.079 +deprioritized. We can also say that we really don't want + +00:22:18.080 --> 00:22:21.599 +the search to contain the word frame by increasing its + +00:22:21.600 --> 00:22:27.199 +importance. So with all these composable pieces, we can + +00:22:27.200 --> 00:22:33.412 +create kind of a search that's tailor-made to our needs. + +00:22:33.413 --> 00:22:35.759 +That concludes this talk. There's a lot more I could talk + +00:22:35.760 --> 00:22:37.799 +about with regards to research, so definitely follow the + +00:22:37.800 --> 00:22:40.639 +project if you're interested. Thanks for watching, and I + +00:22:40.640 --> 00:22:42.240 +hope you enjoy the rest of the conference. |