Parallel Letter Frequency

rust/parallel-letter-frequency/.exercism/config.json

@@ -0,0 +1,42 @@
+{
+  "authors": [
+    "EduardoBautista"
+  ],
+  "contributors": [
+    "andrewclarkson",
+    "ashleygwilliams",
+    "ccouzens",
+    "ClashTheBunny",
+    "coriolinus",
+    "cwhakes",
+    "EduardoBautista",
+    "efx",
+    "ErikSchierboom",
+    "etrepum",
+    "glennpratt",
+    "IanWhitney",
+    "kytrinyx",
+    "lutostag",
+    "mkantor",
+    "nfiles",
+    "petertseng",
+    "rofrol",
+    "sjwarner-bp",
+    "stringparser",
+    "xakon",
+    "ZapAnton"
+  ],
+  "files": {
+    "solution": [
+      "src/lib.rs",
+      "Cargo.toml"
+    ],
+    "test": [
+      "tests/parallel_letter_frequency.rs"
+    ],
+    "example": [
+      ".meta/example.rs"
+    ]
+  },
+  "blurb": "Count the frequency of letters in texts using parallel computation."
+}

rust/parallel-letter-frequency/.gitignore

@@ -0,0 +1,2 @@
+/target
+Cargo.lock

rust/parallel-letter-frequency/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "parallel_letter_frequency"
+version = "0.1.0"
+edition = "2024"
+
+# Not all libraries from crates.io are available in Exercism's test runner.
+# The full list of available libraries is here:
+# https://github.com/exercism/rust-test-runner/blob/main/local-registry/Cargo.toml
+[dependencies]

rust/parallel-letter-frequency/HELP.md

@@ -0,0 +1,89 @@
+# Help
+
+## Running the tests
+
+Execute the tests with:
+
+```bash
+$ cargo test
+```
+
+All but the first test have been ignored. After you get the first test to
+pass, open the tests source file which is located in the `tests` directory
+and remove the `#[ignore]` flag from the next test and get the tests to pass
+again. Each separate test is a function with `#[test]` flag above it.
+Continue, until you pass every test.
+
+If you wish to run _only ignored_ tests without editing the tests source file, use:
+
+```bash
+$ cargo test -- --ignored
+```
+
+If you are using Rust 1.51 or later, you can run _all_ tests with
+
+```bash
+$ cargo test -- --include-ignored
+```
+
+To run a specific test, for example `some_test`, you can use:
+
+```bash
+$ cargo test some_test
+```
+
+If the specific test is ignored, use:
+
+```bash
+$ cargo test some_test -- --ignored
+```
+
+To learn more about Rust tests refer to the online [test documentation][rust-tests].
+
+[rust-tests]: https://doc.rust-lang.org/book/ch11-02-running-tests.html
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit src/lib.rs Cargo.toml` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Rust track's documentation](https://exercism.org/docs/tracks/rust)
+- The [Rust track's programming category on the forum](https://forum.exercism.org/c/programming/rust)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+## Rust Installation
+
+Refer to the [exercism help page][help-page] for Rust installation and learning
+resources.
+
+## Submitting the solution
+
+Generally you should submit all files in which you implemented your solution (`src/lib.rs` in most cases). If you are using any external crates, please consider submitting the `Cargo.toml` file. This will make the review process faster and clearer.
+
+## Feedback, Issues, Pull Requests
+
+Head to [the forum](https://forum.exercism.org/c/programming/rust/) and create a post to provide feedback about an exercise or if you want to help implement new exercises.
+Members of the rust track team are happy to help!
+
+The GitHub [track repository][github] is the home for all of the Rust exercises.
+
+If you want to know more about Exercism, take a look at the [contribution guide].
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+
+[help-page]: https://exercism.org/tracks/rust/learning
+[github]: https://github.com/exercism/rust
+[contribution guide]: https://exercism.org/docs/community/contributors

rust/parallel-letter-frequency/README.md

@@ -0,0 +1,76 @@
+# Parallel Letter Frequency
+
+Welcome to Parallel Letter Frequency on Exercism's Rust Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Count the frequency of letters in texts using parallel computation.
+
+Parallelism is about doing things in parallel that can also be done sequentially.
+A common example is counting the frequency of letters.
+Employ parallelism to calculate the total frequency of each letter in a list of texts.
+
+## Parallel Letter Frequency in Rust
+
+Learn more about concurrency in Rust here:
+
+- [Concurrency](https://doc.rust-lang.org/book/ch16-00-concurrency.html)
+
+## Bonus
+
+This exercise also includes a benchmark, with a sequential implementation as a
+baseline. You can compare your solution to the benchmark. Observe the
+effect different size inputs have on the performance of each. Can you
+surpass the benchmark using concurrent programming techniques?
+
+As of this writing, test::Bencher is unstable and only available on
+*nightly* Rust. Run the benchmarks with Cargo:
+
+```
+cargo bench
+```
+
+If you are using rustup.rs:
+
+```
+rustup run nightly cargo bench
+```
+
+- [Benchmark tests](https://doc.rust-lang.org/stable/unstable-book/library-features/test.html)
+
+Learn more about nightly Rust:
+
+- [Nightly Rust](https://doc.rust-lang.org/book/appendix-07-nightly-rust.html)
+- [Installing Rust nightly](https://rust-lang.github.io/rustup/concepts/channels.html#working-with-nightly-rust)
+
+## Source
+
+### Created by
+
+- @EduardoBautista
+
+### Contributed to by
+
+- @andrewclarkson
+- @ashleygwilliams
+- @ccouzens
+- @ClashTheBunny
+- @coriolinus
+- @cwhakes
+- @EduardoBautista
+- @efx
+- @ErikSchierboom
+- @etrepum
+- @glennpratt
+- @IanWhitney
+- @kytrinyx
+- @lutostag
+- @mkantor
+- @nfiles
+- @petertseng
+- @rofrol
+- @sjwarner-bp
+- @stringparser
+- @xakon
+- @ZapAnton

rust/parallel-letter-frequency/benches/benchmark.rs

@@ -0,0 +1,102 @@
+#![feature(test)]
+extern crate parallel_letter_frequency;
+extern crate test;
+
+use std::collections::HashMap;
+use test::Bencher;
+
+#[bench]
+fn bench_tiny_parallel(b: &mut Bencher) {
+    let tiny = &["a"];
+    b.iter(|| parallel_letter_frequency::frequency(tiny, 3));
+}
+
+#[bench]
+fn bench_tiny_sequential(b: &mut Bencher) {
+    let tiny = &["a"];
+    b.iter(|| frequency(tiny));
+}
+
+#[bench]
+fn bench_small_parallel(b: &mut Bencher) {
+    let texts = all_texts(1);
+    b.iter(|| parallel_letter_frequency::frequency(&texts, 3));
+}
+
+#[bench]
+fn bench_small_sequential(b: &mut Bencher) {
+    let texts = all_texts(1);
+    b.iter(|| frequency(&texts));
+}
+
+#[bench]
+fn bench_large_parallel(b: &mut Bencher) {
+    let texts = all_texts(30);
+    b.iter(|| parallel_letter_frequency::frequency(&texts, 3));
+}
+
+#[bench]
+fn bench_large_sequential(b: &mut Bencher) {
+    let texts = all_texts(30);
+    b.iter(|| frequency(&texts));
+}
+
+/// Simple sequential char frequency. Can it be beat?
+pub fn frequency(texts: &[&str]) -> HashMap<char, usize> {
+    let mut map = HashMap::new();
+
+    for line in texts {
+        for chr in line.chars().filter(|c| c.is_alphabetic()) {
+            if let Some(c) = chr.to_lowercase().next() {
+                (*map.entry(c).or_insert(0)) += 1;
+            }
+        }
+    }
+
+    map
+}
+
+fn all_texts(repeat: usize) -> Vec<&'static str> {
+    [ODE_AN_DIE_FREUDE, WILHELMUS, STAR_SPANGLED_BANNER]
+        .iter()
+        .cycle()
+        .take(3 * repeat)
+        .flat_map(|anthem| anthem.iter().cloned())
+        .collect()
+}
+
+// Poem by Friedrich Schiller. The corresponding music is the European Anthem.
+pub const ODE_AN_DIE_FREUDE: [&str; 8] = [
+    "Freude schöner Götterfunken",
+    "Tochter aus Elysium,",
+    "Wir betreten feuertrunken,",
+    "Himmlische, dein Heiligtum!",
+    "Deine Zauber binden wieder",
+    "Was die Mode streng geteilt;",
+    "Alle Menschen werden Brüder,",
+    "Wo dein sanfter Flügel weilt.",
+];
+
+// Dutch national anthem
+pub const WILHELMUS: [&str; 8] = [
+    "Wilhelmus van Nassouwe",
+    "ben ik, van Duitsen bloed,",
+    "den vaderland getrouwe",
+    "blijf ik tot in den dood.",
+    "Een Prinse van Oranje",
+    "ben ik, vrij, onverveerd,",
+    "den Koning van Hispanje",
+    "heb ik altijd geëerd.",
+];
+
+// American national anthem
+pub const STAR_SPANGLED_BANNER: [&str; 8] = [
+    "O say can you see by the dawn's early light,",
+    "What so proudly we hailed at the twilight's last gleaming,",
+    "Whose broad stripes and bright stars through the perilous fight,",
+    "O'er the ramparts we watched, were so gallantly streaming?",
+    "And the rockets' red glare, the bombs bursting in air,",
+    "Gave proof through the night that our flag was still there;",
+    "O say does that star-spangled banner yet wave,",
+    "O'er the land of the free and the home of the brave?",
+];

rust/parallel-letter-frequency/src/lib.rs

@@ -0,0 +1,41 @@
+use std::any::Any;
+use std::collections::HashMap;
+use std::thread;
+
+pub fn frequency(input: &[&str], worker_count: usize) -> HashMap<char, usize> {
+    if input.is_empty() {
+        return HashMap::<char, usize>::new();
+    }
+
+    let worker_count = worker_count.max(1);
+
+    thread::scope(|s| {
+        let chunk_size = input.len().div_ceil(worker_count);
+        let mut handles: Vec<_> = input
+            .chunks(chunk_size)
+            .map(|chunk| {
+                s.spawn(move || {
+                    let mut proxy_map = HashMap::new();
+                    chunk
+                        .iter()
+                        .flat_map(|line| line.chars())
+                        .filter(|char| char.is_alphabetic())
+                        .flat_map(|char_slice| char_slice.to_lowercase())
+                        .for_each(|char| {
+                            *proxy_map.entry(char).or_insert(0) += 1;
+                        });
+                    proxy_map
+                })
+            })
+            .collect();
+        handles
+            .into_iter()
+            .map(|x| x.join().unwrap())
+            .fold(HashMap::new(), |mut acc, map| {
+                for (char, count) in map {
+                    *acc.entry(char).or_insert(0) += count;
+                }
+                acc
+            })
+    })
+}

rust/parallel-letter-frequency/tests/parallel_letter_frequency.rs

@@ -0,0 +1,347 @@
+use std::collections::HashMap;
+
+use parallel_letter_frequency as frequency;
+
+#[test]
+fn no_texts() {
+    assert_eq!(frequency::frequency(&[], 4), HashMap::new());
+}
+
+#[test]
+fn one_text_with_one_letter() {
+    let mut hm = HashMap::new();
+    hm.insert('a', 1);
+    assert_eq!(frequency::frequency(&["a"], 4), hm);
+}
+
+#[test]
+fn one_text_with_multiple_letters() {
+    let mut hm = HashMap::new();
+    hm.insert('b', 2);
+    hm.insert('c', 3);
+    hm.insert('d', 1);
+    assert_eq!(frequency::frequency(&["bbcccd"], 4), hm);
+}
+
+#[test]
+fn two_texts_with_one_letter() {
+    let mut hm = HashMap::new();
+    hm.insert('e', 1);
+    hm.insert('f', 1);
+    assert_eq!(frequency::frequency(&["e", "f"], 4), hm);
+}
+
+#[test]
+fn two_texts_with_multiple_letters() {
+    let mut hm = HashMap::new();
+    hm.insert('g', 2);
+    hm.insert('h', 3);
+    hm.insert('i', 1);
+    assert_eq!(frequency::frequency(&["ggh", "hhi"], 4), hm);
+}
+
+#[test]
+fn case_insensitivity() {
+    let mut hm = HashMap::new();
+    hm.insert('a', 2);
+    assert_eq!(frequency::frequency(&["aA"], 4), hm);
+}
+
+#[test]
+fn many_empty_lines() {
+    let v = vec![""; 1000];
+    assert_eq!(frequency::frequency(&v[..], 4), HashMap::new());
+}
+
+#[test]
+fn ignore_whitespace() {
+    let v = ["   ", "\t", "\r\n"];
+    assert_eq!(frequency::frequency(&v[..], 4), HashMap::new());
+}
+
+#[test]
+fn many_times_same_text() {
+    let v = vec!["abc"; 1000];
+    let mut hm = HashMap::new();
+    hm.insert('a', 1000);
+    hm.insert('b', 1000);
+    hm.insert('c', 1000);
+    assert_eq!(frequency::frequency(&v[..], 4), hm);
+}
+
+#[test]
+fn punctuation_doesnt_count() {
+    assert!(!frequency::frequency(&WILHELMUS, 4).contains_key(&','));
+}
+
+#[test]
+fn numbers_dont_count() {
+    assert!(!frequency::frequency(&["Testing, 1, 2, 3"], 4).contains_key(&'1'));
+}
+
+#[test]
+fn unicode_letters() {
+    let mut hm = HashMap::new();
+    hm.insert('本', 1);
+    hm.insert('φ', 1);
+    hm.insert('ほ', 1);
+    hm.insert('ø', 1);
+    let v = ["本", "φ", "ほ", "ø"];
+    assert_eq!(frequency::frequency(&v, 4), hm);
+}
+
+#[test]
+fn all_three_anthems_1_worker() {
+    let mut v = Vec::new();
+    // These constants can be found under the last test if you wish to see them
+    for anthem in [ODE_AN_DIE_FREUDE, WILHELMUS, STAR_SPANGLED_BANNER].iter() {
+        for line in anthem.iter() {
+            v.push(*line);
+        }
+    }
+    let freqs = frequency::frequency(&v[..], 1);
+    assert_eq!(freqs.get(&'a'), Some(&49));
+    assert_eq!(freqs.get(&'t'), Some(&56));
+    assert_eq!(freqs.get(&'ü'), Some(&2));
+}
+
+#[test]
+fn all_three_anthems_3_workers() {
+    let mut v = Vec::new();
+    for anthem in [ODE_AN_DIE_FREUDE, WILHELMUS, STAR_SPANGLED_BANNER].iter() {
+        for line in anthem.iter() {
+            v.push(*line);
+        }
+    }
+    let freqs = frequency::frequency(&v[..], 3);
+    assert_eq!(freqs.get(&'a'), Some(&49));
+    assert_eq!(freqs.get(&'t'), Some(&56));
+    assert_eq!(freqs.get(&'ü'), Some(&2));
+}
+
+#[test]
+fn non_integer_multiple_of_threads() {
+    let v = vec!["abc"; 999];
+    let mut hm = HashMap::new();
+    hm.insert('a', 999);
+    hm.insert('b', 999);
+    hm.insert('c', 999);
+    assert_eq!(frequency::frequency(&v[..], 4), hm);
+}
+
+#[test]
+fn large_texts() {
+    let expected: HashMap<char, usize> = [
+        ('a', 845),
+        ('b', 155),
+        ('c', 278),
+        ('d', 359),
+        ('e', 1143),
+        ('f', 222),
+        ('g', 187),
+        ('h', 507),
+        ('i', 791),
+        ('j', 12),
+        ('k', 67),
+        ('l', 423),
+        ('m', 288),
+        ('n', 833),
+        ('o', 791),
+        ('p', 197),
+        ('q', 8),
+        ('r', 432),
+        ('s', 700),
+        ('t', 1043),
+        ('u', 325),
+        ('v', 111),
+        ('w', 223),
+        ('x', 7),
+        ('y', 251),
+    ]
+    .into_iter()
+    .collect();
+
+    assert_eq!(frequency::frequency(&DOSTOEVSKY, 4), expected);
+}
+
+// Poem by Friedrich Schiller. The corresponding music is the European Anthem.
+const ODE_AN_DIE_FREUDE: [&str; 8] = [
+    "Freude schöner Götterfunken",
+    "Tochter aus Elysium,",
+    "Wir betreten feuertrunken,",
+    "Himmlische, dein Heiligtum!",
+    "Deine Zauber binden wieder",
+    "Was die Mode streng geteilt;",
+    "Alle Menschen werden Brüder,",
+    "Wo dein sanfter Flügel weilt.",
+];
+
+// Dutch national anthem
+const WILHELMUS: [&str; 8] = [
+    "Wilhelmus van Nassouwe",
+    "ben ik, van Duitsen bloed,",
+    "den vaderland getrouwe",
+    "blijf ik tot in den dood.",
+    "Een Prinse van Oranje",
+    "ben ik, vrij, onverveerd,",
+    "den Koning van Hispanje",
+    "heb ik altijd geëerd.",
+];
+
+// American national anthem
+const STAR_SPANGLED_BANNER: [&str; 8] = [
+    "O say can you see by the dawn's early light,",
+    "What so proudly we hailed at the twilight's last gleaming,",
+    "Whose broad stripes and bright stars through the perilous fight,",
+    "O'er the ramparts we watched, were so gallantly streaming?",
+    "And the rockets' red glare, the bombs bursting in air,",
+    "Gave proof through the night that our flag was still there;",
+    "O say does that star-spangled banner yet wave,",
+    "O'er the land of the free and the home of the brave?",
+];
+
+const DOSTOEVSKY: [&str; 4] = [
+    r#"
+    I am a sick man.... I am a spiteful man. I am an unattractive man.
+    I believe my liver is diseased. However, I know nothing at all about my disease, and do not
+    know for certain what ails me. I don't consult a doctor for it,
+    and never have, though I have a respect for medicine and doctors.
+    Besides, I am extremely superstitious, sufficiently so to respect medicine,
+    anyway (I am well-educated enough not to be superstitious, but I am superstitious).
+    No, I refuse to consult a doctor from spite.
+    That you probably will not understand. Well, I understand it, though.
+    Of course, I can't explain who it is precisely that I am mortifying in this case by my spite:
+    I am perfectly well aware that I cannot "pay out" the doctors by not consulting them;
+    I know better than anyone that by all this I am only injuring myself and no one else.
+    But still, if I don't consult a doctor it is from spite.
+    My liver is bad, well - let it get worse!
+    I have been going on like that for a long time - twenty years. Now I am forty.
+    I used to be in the government service, but am no longer.
+    I was a spiteful official. I was rude and took pleasure in being so.
+    I did not take bribes, you see, so I was bound to find a recompense in that, at least.
+    (A poor jest, but I will not scratch it out. I wrote it thinking it would sound very witty;
+    but now that I have seen myself that I only wanted to show off in a despicable way -
+    I will not scratch it out on purpose!) When petitioners used to come for
+    information to the table at which I sat, I used to grind my teeth at them,
+    and felt intense enjoyment when I succeeded in making anybody unhappy.
+    I almost did succeed. For the most part they were all timid people - of course,
+    they were petitioners. But of the uppish ones there was one officer in particular
+    I could not endure. He simply would not be humble, and clanked his sword in a disgusting way.
+    I carried on a feud with him for eighteen months over that sword. At last I got the better of him.
+    He left off clanking it. That happened in my youth, though. But do you know,
+    gentlemen, what was the chief point about my spite? Why, the whole point,
+    the real sting of it lay in the fact that continually, even in the moment of the acutest spleen,
+    I was inwardly conscious with shame that I was not only not a spiteful but not even an embittered man,
+    that I was simply scaring sparrows at random and amusing myself by it.
+    I might foam at the mouth, but bring me a doll to play with, give me a cup of tea with sugar in it,
+    and maybe I should be appeased. I might even be genuinely touched,
+    though probably I should grind my teeth at myself afterwards and lie awake at night with shame for
+    months after. That was my way. I was lying when I said just now that I was a spiteful official.
+    I was lying from spite. I was simply amusing myself with the petitioners and with the officer,
+    and in reality I never could become spiteful. I was conscious every moment in myself of many,
+    very many elements absolutely opposite to that. I felt them positively swarming in me,
+    these opposite elements. I knew that they had been swarming in me all my life and craving some outlet from me,
+    but I would not let them, would not let them, purposely would not let them come out.
+    They tormented me till I was ashamed: they drove me to convulsions and - sickened me, at last,
+    how they sickened me!
+    "#,
+    r#"
+    Gentlemen, I am joking, and I know myself that my jokes are not brilliant,
+    but you know one can take everything as a joke. I am, perhaps, jesting against the grain.
+    Gentlemen, I am tormented by questions; answer them for me. You, for instance, want to cure men of their
+    old habits and reform their will in accordance with science and good sense.
+    But how do you know, not only that it is possible, but also that it is
+    desirable to reform man in that way? And what leads you to the conclusion that man's
+    inclinations need reforming? In short, how do you know that such a reformation will be a benefit to man?
+    And to go to the root of the matter, why are you so positively convinced that not to act against
+    his real normal interests guaranteed by the conclusions of reason and arithmetic is certainly always
+    advantageous for man and must always be a law for mankind? So far, you know,
+    this is only your supposition. It may be the law of logic, but not the law of humanity.
+    You think, gentlemen, perhaps that I am mad? Allow me to defend myself. I agree that man
+    is pre-eminently a creative animal, predestined to strive consciously for an object and to engage in engineering -
+    that is, incessantly and eternally to make new roads, wherever
+    they may lead. But the reason why he wants sometimes to go off at a tangent may just be that he is
+    predestined to make the road, and perhaps, too, that however stupid the "direct"
+    practical man may be, the thought sometimes will occur to him that the road almost always does lead
+    somewhere, and that the destination it leads to is less important than the process
+    of making it, and that the chief thing is to save the well-conducted child from despising engineering,
+    and so giving way to the fatal idleness, which, as we all know,
+    is the mother of all the vices. Man likes to make roads and to create, that is a fact beyond dispute.
+    But why has he such a passionate love for destruction and chaos also?
+    Tell me that! But on that point I want to say a couple of words myself. May it not be that he loves
+    chaos and destruction (there can be no disputing that he does sometimes love it)
+    because he is instinctively afraid of attaining his object and completing the edifice he is constructing?
+    Who knows, perhaps he only loves that edifice from a distance, and is by no means
+    in love with it at close quarters; perhaps he only loves building it and does not want to live in it,
+    but will leave it, when completed, for the use of les animaux domestiques -
+    such as the ants, the sheep, and so on. Now the ants have quite a different taste.
+    They have a marvellous edifice of that pattern which endures for ever - the ant-heap.
+    With the ant-heap the respectable race of ants began and with the ant-heap they will probably end,
+    which does the greatest credit to their perseverance and good sense. But man is a frivolous and
+    incongruous creature, and perhaps, like a chess player, loves the process of the game, not the end of it.
+    And who knows (there is no saying with certainty), perhaps the only goal on earth
+    to which mankind is striving lies in this incessant process of attaining, in other words,
+    in life itself, and not in the thing to be attained, which must always be expressed as a formula,
+    as positive as twice two makes four, and such positiveness is not life, gentlemen,
+    but is the beginning of death.
+    "#,
+    r#"
+    But these are all golden dreams. Oh, tell me, who was it first announced,
+    who was it first proclaimed, that man only does nasty things because he does not know his own interests;
+    and that if he were enlightened, if his eyes were opened to his real normal interests,
+    man would at once cease to do nasty things, would at once become good and noble because,
+    being enlightened and understanding his real advantage, he would see his own advantage in the
+    good and nothing else, and we all know that not one man can, consciously, act against his own interests,
+    consequently, so to say, through necessity, he would begin doing good? Oh, the babe! Oh, the pure,
+    innocent child! Why, in the first place, when in all these thousands of years has there been a time
+    when man has acted only from his own interest? What is to be done with the millions of facts that bear
+    witness that men, consciously, that is fully understanding their real interests, have left them in the
+    background and have rushed headlong on another path, to meet peril and danger,
+    compelled to this course by nobody and by nothing, but, as it were, simply disliking the beaten track,
+    and have obstinately, wilfully, struck out another difficult, absurd way, seeking it almost in the darkness.
+    So, I suppose, this obstinacy and perversity were pleasanter to them than any advantage....
+    Advantage! What is advantage? And will you take it upon yourself to define with perfect accuracy in what the
+    advantage of man consists? And what if it so happens that a man's advantage, sometimes, not only may,
+    but even must,  consist in his desiring in certain cases what is harmful to himself and not advantageous.
+    And if so, if there can be such a case, the whole principle falls into dust. What do you think -
+    are there such cases? You laugh; laugh away, gentlemen, but only answer me: have man's advantages been
+    reckoned up with perfect certainty? Are there not some which not only have not been included but cannot
+    possibly be included under any classification? You see, you gentlemen have, to the best of my knowledge,
+    taken your whole register of human advantages from the averages of statistical figures and
+    politico-economical formulas. Your advantages are prosperity, wealth, freedom, peace - and so on, and so on.
+    So that the man who should, for instance, go openly and knowingly in opposition to all that list would to your thinking,
+    and indeed mine, too, of course, be an obscurantist or an absolute madman: would not he? But, you know, this is
+    what is surprising: why does it so happen that all these statisticians,  sages and lovers of humanity,
+    when they reckon up human advantages invariably leave out one? They don't even take it into their reckoning
+    in the form in which it should be taken, and the whole reckoning depends upon that. It would be no greater matter,
+    they would simply have to take it, this advantage, and add it to the list. But the trouble is, that this strange
+    advantage does not fall under any classification and is not in place in any list. I have a friend for instance ...
+    Ech! gentlemen, but of course he is your friend, too; and indeed there is no one, no one to whom he is not a friend!
+    "#,
+    r#"
+    Yes, but here I come to a stop! Gentlemen, you must excuse me for being over-philosophical;
+    it's the result of forty years underground! Allow me to indulge my fancy. You see, gentlemen, reason is an excellent thing,
+    there's no disputing that, but reason is nothing but reason and satisfies only the rational side of man's nature,
+    while will is a manifestation of the whole life, that is, of the whole human life including reason and all the impulses.
+    And although our life, in this manifestation of it, is often worthless, yet it is life and not simply extracting square roots.
+    Here I, for instance, quite naturally want to live, in order to satisfy all my capacities for life, and not simply my capacity
+    for reasoning, that is, not simply one twentieth of my capacity for life. What does reason know? Reason only knows what it has
+    succeeded in learning (some things, perhaps, it will never learn; this is a poor comfort, but why not say so frankly?)
+    and human nature acts as a whole, with everything that is in it, consciously or unconsciously, and, even it if goes wrong, it lives.
+    I suspect, gentlemen, that you are looking at me with compassion; you tell me again that an enlightened and developed man,
+    such, in short, as the future man will be, cannot consciously desire anything disadvantageous to himself, that that can be proved mathematically.
+    I thoroughly agree, it can - by mathematics. But I repeat for the hundredth time, there is one case, one only, when man may consciously, purposely,
+    desire what is injurious to himself, what is stupid, very stupid - simply in order to have the right to desire for himself even what is very stupid
+    and not to be bound by an obligation to desire only what is sensible. Of course, this very stupid thing, this caprice of ours, may be in reality,
+    gentlemen, more advantageous for us than anything else on earth, especially in certain cases. And in particular it may be more advantageous than
+    any advantage even when it does us obvious harm, and contradicts the soundest conclusions of our reason concerning our advantage -
+    for in any circumstances it preserves for us what is most precious and most important - that is, our personality, our individuality.
+    Some, you see, maintain that this really is the most precious thing for mankind; choice can, of course, if it chooses, be in agreement
+    with reason; and especially if this be not abused but kept within bounds. It is profitable and some- times even praiseworthy.
+    But very often, and even most often, choice is utterly and stubbornly opposed to reason ... and ... and ... do you know that that,
+    too, is profitable, sometimes even praiseworthy? Gentlemen, let us suppose that man is not stupid. (Indeed one cannot refuse to suppose that,
+    if only from the one consideration, that, if man is stupid, then who is wise?) But if he is not stupid, he is monstrously ungrateful!
+    Phenomenally ungrateful. In fact, I believe that the best definition of man is the ungrateful biped. But that is not all, that is not his worst defect;
+    his worst defect is his perpetual moral obliquity, perpetual - from the days of the Flood to the Schleswig-Holstein period.
+    "#,
+];