init: first working impl of determinant

types: added initial matrix definition and impl blocks

.envrc

@@ -0,0 +1,3 @@
+source_url "https://raw.githubusercontent.com/cachix/devenv/82c0147677e510b247d8b9165c54f73d32dfd899/direnvrc" "sha256-7u4iDd1nZpxL4tCzmPG0dQgC5V+/44Ba+tHkPob1v2k="
+
+use devenv

.gitignore

@@ -0,0 +1,14 @@
+# Devenv
+.devenv*
+devenv.local.nix
+
+# direnv
+.direnv
+
+# pre-commit
+.pre-commit-config.yaml
+
+
+# Added by cargo
+
+/target

Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "matrix-rs"
+version = "0.1.0"

Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "matrix-rs"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]

devenv.lock

@@ -0,0 +1,100 @@
+{
+  "nodes": {
+    "devenv": {
+      "locked": {
+        "dir": "src/modules",
+        "lastModified": 1737321981,
+        "owner": "cachix",
+        "repo": "devenv",
+        "rev": "a30b871f21bfc987b65356909d04186a18adf0c6",
+        "type": "github"
+      },
+      "original": {
+        "dir": "src/modules",
+        "owner": "cachix",
+        "repo": "devenv",
+        "type": "github"
+      }
+    },
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1733328505,
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "ff81ac966bb2cae68946d5ed5fc4994f96d0ffec",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "gitignore": {
+      "inputs": {
+        "nixpkgs": [
+          "pre-commit-hooks",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1709087332,
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "rev": "637db329424fd7e46cf4185293b9cc8c88c95394",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1733477122,
+        "owner": "cachix",
+        "repo": "devenv-nixpkgs",
+        "rev": "7bd9e84d0452f6d2e63b6e6da29fe73fac951857",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "ref": "rolling",
+        "repo": "devenv-nixpkgs",
+        "type": "github"
+      }
+    },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "gitignore": "gitignore",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1737465171,
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "9364dc02281ce2d37a1f55b6e51f7c0f65a75f17",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "devenv": "devenv",
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

devenv.nix

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+{ pkgs, lib, config, inputs, ... }:
+
+{
+  # https://devenv.sh/basics/
+  env.GREET = "devenv";
+
+  # https://devenv.sh/packages/
+  packages = [ pkgs.git ];
+
+  # https://devenv.sh/languages/
+  languages.rust.enable = true;
+
+  # https://devenv.sh/processes/
+  processes.cargo-watch.exec = "cargo-watch";
+
+  # https://devenv.sh/services/
+  # services.postgres.enable = true;
+
+  # https://devenv.sh/scripts/
+  scripts.hello.exec = ''
+    echo hello from $GREET
+  '';
+
+  enterShell = ''
+    hello
+    git --version
+  '';
+
+  # https://devenv.sh/tasks/
+  # tasks = {
+  #   "myproj:setup".exec = "mytool build";
+  #   "devenv:enterShell".after = [ "myproj:setup" ];
+  # };
+
+  # https://devenv.sh/tests/
+  enterTest = ''
+    echo "Running tests"
+    git --version | grep --color=auto "${pkgs.git.version}"
+  '';
+
+  # https://devenv.sh/pre-commit-hooks/
+  pre-commit.hooks = { 
+    clippy.enable = true;
+    commitizen.enable = true;
+    shellcheck.enable = true; 
+  };
+
+  # See full reference at https://devenv.sh/reference/options/
+}

devenv.yaml

@@ -0,0 +1,15 @@
+# yaml-language-server: $schema=https://devenv.sh/devenv.schema.json
+inputs:
+  nixpkgs:
+    url: github:cachix/devenv-nixpkgs/rolling
+
+# If you're using non-OSS software, you can set allowUnfree to true.
+# allowUnfree: true
+
+# If you're willing to use a package that's vulnerable
+# permittedInsecurePackages:
+#  - "openssl-1.1.1w"
+
+# If you have more than one devenv you can merge them
+#imports:
+# - ./backend

src/main.rs

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+use types::matrix::Matrix;
+
+mod types;
+fn main() {
+    println!("Hello, world!");
+    let m = Matrix::from_str("1,2\n3,4".to_string());
+    let d = m.determinant();
+    println!("{}", d);
+}

src/types.rs

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+pub mod matrix;

src/types/matrix.rs

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+use std::str::FromStr;
+/// Matrix
+pub struct Matrix {
+    pub nrows: usize,
+    pub ncols: usize,
+    pub data: Vec<Vec<i32>>,
+}
+impl Matrix {
+    pub fn new(data: Vec<Vec<i32>>) -> Matrix {
+        Matrix {
+            nrows: data[0].len(),
+            ncols: data.len(),
+            data,
+        }
+    }
+    pub fn from_str(s: String) -> Matrix {
+        let mut d: Vec<Vec<i32>> = Vec::new();
+        let rows_iter = s.split('\n');
+        for (_i, txt) in rows_iter.enumerate() {
+            let mut r: Vec<i32> = Vec::new();
+            for (_j, ch) in txt.split(',').enumerate() {
+                let parsed = match i32::from_str(ch) {
+                    Ok(n) => n,
+                    Err(e) => panic!("Err: {}", e),
+                };
+                r.push(parsed);
+            }
+            d.push(r);
+        }
+        Matrix::new(d)
+    }
+    pub fn is_square(&self) -> bool {
+        &self.nrows == &self.ncols
+    }
+    pub fn splice(&self, at_index: usize) -> Matrix {
+        let mut data: Vec<Vec<i32>> = Vec::new();
+        for i in 0..self.data.len() {
+            if i == at_index {continue;}
+            let mut r: Vec<i32> = Vec::new(); 
+            for j in 0..self.data[i].len() {
+                if j == at_index {continue;}
+                r.push(self.data[i][j]);
+            }
+            data.push(r);
+        }
+        Matrix::new(data)
+    }
+    pub fn determinant(&self) -> i32 {
+        if self.nrows == 2 && self.nrows == 2 {
+            return &self.data[0][0] * &self.data[0][1] - &self.data[1][0] * &self.data[1][1];
+        }
+        let mut tmp = 0;
+        for (i, n) in self.data[0].iter().enumerate() {
+            let mult = if i % 2 == 0 { -*n } else { *n };
+            let eval = self.splice(i).determinant();
+            tmp += mult * eval;
+        }
+        tmp
+    }
+    pub fn transpose(&self) -> Matrix {
+        let mut new_data = Vec::<Vec<i32>>::new();
+        for i in 0..self.nrows {
+            let mut new_row = Vec::<i32>::new();
+            for j in 0..self.ncols {
+                new_row.push(self.data[j][i]);
+            }
+            new_data.push(new_row);
+        }
+        Matrix {
+            nrows: self.ncols,
+            ncols: self.nrows,
+            data: new_data,
+        }
+    }
+}