Hi Simon,

On 9/13/24 10:12, Simon Tournier wrote:

| tor                   | Tor related; ~torbrowser~ somewhere near top. |

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix search tor | recsel -p name,relevance | head -8
name: tor
relevance: 208

name: tor-client
relevance: 169

name: torsocks
relevance: 103
--8<---------------cut here---------------end--------------->8---

Compared to current:

--8<---------------cut here---------------start------------->8---
$ guix search tor | recsel -p name,relevance | head -8
name: tor
relevance: 47

name: ghc-storablevector
relevance: 29

name: tor-client
relevance: 28
--8<---------------cut here---------------end--------------->8---

However, the position move from 225th to 19th.

    $ guix search tor | recsel -P name | grep -n torbrowser
    225:torbrowser

    $ ./pre-inst-env guix search tor | recsel -P name | grep -n torbrowser
    19:torbrowser

Similarly as ’dig’, the description of ’torbrowser’ package could be
improvement.  Because ’guix search tor browser’ returns nothing.

Does ~torbrowser~ not appear as the third result in all three cases for you when running =guix search tor browser=?

Otherwise, if you meant =guix search tor= to find ~torbrowser~: perhaps it should be higher ranked, but it could be argued that patch v1's behavior is still more optimal in this aspect considering all results above ~torbrowser~ it are indeed related to Tor.

| Keyword(s) with poor  | Expectations                                  |
| results before        |                                               |
|-----------------------+-----------------------------------------------|
| dig                   | ~bind~ near top.                              |

Hum, indeed and I do not know if we can improve here.  Well, it’s hard
to improve for short terms, BTW.

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix search dig | recsel -p name,relevance | head -8
name: go-go-uber-org-dig
relevance: 104

name: rust-num-bigint-dig
relevance: 78

name: rust-num-bigint-dig
relevance: 78
--8<---------------cut here---------------end--------------->8---

Compared to current:

--8<---------------cut here---------------start------------->8---
$ guix search dig | recsel -p name,relevance | head -8
name: sysdig
relevance: 24

name: texlive-pedigree-perl
relevance: 13

name: ruby-net-http-digest-auth
relevance: 13
--8<---------------cut here---------------end--------------->8---

Indeed, 17th position is better than 609th.  But if you add a term as
’dns’, bang! :-)  Well, BTW the description of ’bind’ could be a bit
improved because the word network does not appear.  Anyway. :-)

[...]

| rsh                   | ~inetutils~ near top.                         |

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix search rsh | recsel -p name,relevance | head -8
name: inetutils
relevance: 26

name: emacs-tramp
relevance: 26

name: rust-borsh-schema-derive-internal
relevance: 22
--8<---------------cut here---------------end--------------->8---

Compared to current:

--8<---------------cut here---------------start------------->8---
$ guix search rsh | recsel -p name,relevance | head -8
name: go-sigs-k8s-io-yaml
relevance: 14

name: python-pymarshal
relevance: 13

name: emacs-powershell
relevance: 13
--8<---------------cut here---------------end--------------->8---

[...]

| gcc                   | ~gcc-toolchain~ near top.                     |

Indeed, something is unexpected.  Well, first:

    $ guix search gcc | recsel -CP name | uniq | head -8
    gccgo
    gfortran-toolchain
    gdc-toolchain
    gcc-toolchain
    gcc-cross-x86_64-w64-mingw32-toolchain
    gcc-cross-or1k-elf-toolchain
    gcc-cross-i686-w64-mingw32-toolchain
    gcc-cross-avr-toolchain

    $ guix search gcc | recsel -CP name | uniq -c | sort -rn | head -8
         18 llvm
         12 gcc-toolchain
          6 libgccjit
          6 gccgo
          3 isl
          2 libstdc++-doc
          2 java-commons-cli
          2 gdc-toolchain

Other said, the packages with multi-versions decrease the experience.
Well, that had already by “improved” [1] with some SEO. ;-)  Indeed,
maybe the relevance should be improved.

Second, gccgo has a relevance score of 22 with the only term ’gcc’,
compared to gcc-toolchain scoring at 15.

    gccgo        gcc-toolchain
  4 * 1 * 1      4 * 1 * 1  
+ 2 * 5 * 1    + 2 * 1 * 1  
+ 1 * 0        + 1 * 0      
+ 3 * 1 * 1    + 3 * 1 * 1  
+ 2 * 0        + 2 * 1 * 3  
+ 1 * 5 * 1    + 1 * 0      
= 22           = 15         

This is unexpected.  And, IMHO that’s bug!  In the description of
gcc-toolchain, the term ’gcc’ appears 3 times but it only score with ’1’
instead of ’5’.

As the patch try to address, the main issue is:

  (define (score regexp str)
    (fold-matches regexp str 0
                  (lambda (m score)
                    (+ score
                       (if (string=? (match:substring m) str)
                           5             ;exact match
                           1)))))

Here the exact match does not consider a substring exact match.  For
instance, one would consider that the term ’gcc’ exactly matches in
“some GCC thing”.  Considering the current implementation, that’s not
the case.  For instance, a snippet as the procedure ’scoring’:

--8<---------------cut here---------------start------------->8---
scheme@(guix-user)> ,use(ice-9 regex)
scheme@(guix-user)> (define regexp (make-regexp "gcc" regexp/icase))
scheme@(guix-user)> (define str "some GCC thing")
scheme@(guix-user)> (fold-matches regexp str 0
    (lambda (m res)
      (+ res
        (if (string=? (match:substring m) str)
          5 1))))
$2 = 1
--8<---------------cut here---------------end--------------->8---


See v2 for my proposal fixing this.

Please note that this v2 gives the same ranking for torbrowser.  And
also improve the situation with gcc-toolchain.

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix search gcc | recsel -CP name | grep -n gcc-toolchain
1:gcc-toolchain
2:gcc-toolchain
3:gcc-toolchain
4:gcc-toolchain
5:gcc-toolchain
6:gcc-toolchain
7:gcc-toolchain
8:gcc-toolchain
9:gcc-toolchain
10:gcc-toolchain
11:gcc-toolchain
12:gcc-toolchain

$ ./pre-inst-env guix search tor | recsel -CP name | grep -n torbrowser
7:torbrowser

$ ./pre-inst-env guix search dig | recsel -CP name | grep -n bind
44:bind
--8<---------------cut here---------------end--------------->8---

However, inetutils is still at 44th with the only one term ’rsh’.  I
would suggest to do some tweak with the description.

And including a relevant part of your message from #70689:

Again, considering the case at hand: If instead of 3 randomly picked in
v2 of #73220, we would pick 7, then inetutils is ranked first.

Yeah, maybe 3 isn’t enough… And maybe 7 is a good choice.

Note that I also gave the same treatment to exact match scores, although not as extremely weighed (only double the whole word score in v1).

In the case of ~inetutils~, for example, this formula guarantees that if I were to search =rsh= - which is a common subword, but itself has a very unique meaning - ~inetutils~ /always/ shows up at or near the top along with other rsh-related packages, assuming no exact matches.

In other words, the intention would be to have the calculations set up such that they implicitly "categorize" object rankings into a (rough) hierarchy of the following:

|--------------------------------------------| | Objects with at least one exact match | |--------------------------------------------| | Objects with at least one whole word match | |--------------------------------------------| | Objects with only substring matches | |--------------------------------------------|

I opted to switch to counting a maximum of one match per field, which helps
with cases where a common subword matches /many/ times in packages with longer
descriptions, pushing more relevant packages down.  In multi-term searches,
the unique terms - which are naturally rarer - also contribute to a larger
percentage of the score as a result of these changes.

Having matches with only one word boundary be scored as 2 instead of 1 was
done with the reasoning that a term is more likely to be part of a compound
word name (and thus more relevant) if it is a prefix or suffix; for example,
"gl" in OpenGL, "borg" in borgmatic, and "tor" in torbrowser.

[...]

Closing this message on an unrelated note for future work: I stumbled on an
interesting idea while looking for test cases which suggested reducing the
score of a programming library when its language is not included in search
terms.  It's out of scope for the current issue, but I thought I'd mention it
anyways for potential further improvements.

Well, years ago I thought about implementing TF-IDF [2,3].  Other ideas
[4] are floating around.  Then, we spent some time for making “guix
search” faster [5] and today my TODO is about having an extension
relying on Guile-Xapian.

Therefore, I would prefer keep the ’relevance’ more or less predictable
by only counting the number of occurrences and apply some weights.
Else, for what my opinion is worth, the direction would not be to
re-invent an algorithm but maybe implement some already well-known ones.
TF-IDF [3] is one or Okapi-BM25 is another one, etc.  In all in all,
that what Xapian provides. ;-) And it does it very well!  That’s why I
would be tempted to have a Guix extension relying on Guile-Xapin for
indexing and searching (fast!).

Yes, I had thought about trying something like TF-IDF while looking into the issue, but it seemed much less trivial than changes to a scoring function. The count-once-per-field change was supposed to at least tangentially mimic this behavior and reduce bias towards objects that happen to have very long descriptions but aren't very relevant. It's also needed for my "categorization" math to hold.

Hum, why this:

    guix search ' dig$' dig | recsel -p name,relevance | head -8

does not return the package ’bind’?

It appears the ~regexp/newline~ flag needs to be set for ~make-regexp~. A quick test adding it here [1] seemed to work.

My main concern with v2 is that I don't think whole words are weighed heavily enough, but it provides a simpler solution that still offers improvement, so I'm happy either way.

Thanks for the feedback!

[1] https://git.savannah.gnu.org/cgit/guix.git/tree/guix/scripts/package.scm#n897

Cheers,

aurtzy