From 1d70b482dea611a4b99410bfb9f16fb09fd97193 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maciej=20Krzy=C5=BCanowski?= <krzmaciek@gmail.com>
Date: Sat, 24 Aug 2024 15:30:52 +0200
Subject: [PATCH] Add Zig Matrix example

---
 zig-matrix/.gitignore   |   2 +
 zig-matrix/build.zig    |  26 ++++++++
 zig-matrix/src/main.zig | 132 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 160 insertions(+)
 create mode 100644 zig-matrix/.gitignore
 create mode 100644 zig-matrix/build.zig
 create mode 100644 zig-matrix/src/main.zig

diff --git a/zig-matrix/.gitignore b/zig-matrix/.gitignore
new file mode 100644
index 0000000..dca1103
--- /dev/null
+++ b/zig-matrix/.gitignore
@@ -0,0 +1,2 @@
+zig-out/
+.zig-cache/
diff --git a/zig-matrix/build.zig b/zig-matrix/build.zig
new file mode 100644
index 0000000..84a8b90
--- /dev/null
+++ b/zig-matrix/build.zig
@@ -0,0 +1,26 @@
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+    const exe = b.addExecutable(.{
+        .name = "zig-matrix",
+        .root_source_file = b.path("src/main.zig"),
+        .target = b.host,
+    });
+
+    b.installArtifact(exe);
+
+    const run_exe = b.addRunArtifact(exe);
+    const run_step = b.step("run", "Run the application");
+
+    run_step.dependOn(&run_exe.step);
+
+    const unit_tests = b.addTest(.{
+        .root_source_file = b.path("src/main.zig"),
+        .target = b.host,
+    });
+
+    const test_step = b.step("test", "Run unit tests");
+    const run_unit_tests = b.addRunArtifact(unit_tests);
+
+    test_step.dependOn(&run_unit_tests.step);
+}
diff --git a/zig-matrix/src/main.zig b/zig-matrix/src/main.zig
new file mode 100644
index 0000000..5b11714
--- /dev/null
+++ b/zig-matrix/src/main.zig
@@ -0,0 +1,132 @@
+const std = @import("std");
+
+const MatrixOpError = error{
+    IncompatibleSizes,
+};
+
+const Matrix = struct {
+    allocator: std.mem.Allocator,
+    numbers: []i64,
+    dimensions: []const u64,
+
+    pub fn init(allocator: std.mem.Allocator, dimensions: []const u64) !Matrix {
+        var size: u64 = 1;
+
+        for (dimensions) |dim| {
+            size *= dim;
+        }
+
+        return Matrix{
+            .allocator = allocator,
+            .numbers = try allocator.alloc(i64, size),
+            .dimensions = dimensions,
+        };
+    }
+
+    pub fn fill(self: Matrix, number: i64) void {
+        var i: u64 = 0;
+        while (i < self.numbers.len) {
+            self.numbers[i] = number;
+            i += 1;
+        }
+    }
+
+    pub fn add(self: Matrix, allocator: std.mem.Allocator, other: Matrix) !Matrix {
+        if (!std.mem.eql(u64, self.dimensions, other.dimensions)) {
+            return error.IncompatibleSizes;
+        }
+
+        var result: Matrix = try Matrix.init(allocator, self.dimensions);
+        result.fill(0);
+
+        for (self.numbers, 0..) |num, idx| {
+            result.numbers[idx] += num;
+        }
+
+        for (other.numbers, 0..) |num, idx| {
+            result.numbers[idx] += num;
+        }
+
+        return result;
+    }
+
+    pub fn sub(self: Matrix, allocator: std.mem.Allocator, other: Matrix) !Matrix {
+        if (!std.mem.eql(u64, self.dimensions, other.dimensions)) {
+            return error.IncompatibleSizes;
+        }
+
+        var result: Matrix = try Matrix.init(allocator, self.dimensions);
+        result.fill(0);
+
+        for (self.numbers, 0..) |num, idx| {
+            result.numbers[idx] += num;
+        }
+
+        for (other.numbers, 0..) |num, idx| {
+            result.numbers[idx] -= num;
+        }
+
+        return result;
+    }
+
+    pub fn deinit(self: Matrix) void {
+        self.allocator.free(self.numbers);
+    }
+};
+
+pub fn main() void {
+    std.debug.print("Please use 'zig build test --summary all' to run tests. This example does not have any other runnable code.\n", .{});
+}
+
+test "matrix init" {
+    const mat = try Matrix.init(std.testing.allocator, &[_]u64{ 5, 5 });
+    defer mat.deinit();
+
+    try std.testing.expect(mat.numbers.len == 25);
+}
+
+test "matrix fill" {
+    const mat = try Matrix.init(std.testing.allocator, &[_]u64{ 5, 5 });
+    defer mat.deinit();
+    mat.fill(123);
+
+    for (mat.numbers) |num| {
+        try std.testing.expect(num == 123);
+    }
+}
+
+test "matrix add" {
+    const mat1 = try Matrix.init(std.testing.allocator, &[_]u64{ 2, 2 });
+    defer mat1.deinit();
+    const mat2 = try Matrix.init(std.testing.allocator, &[_]u64{ 2, 2 });
+    defer mat2.deinit();
+
+    mat1.fill(1);
+    mat2.fill(2);
+
+    const mat3 = try mat1.add(std.testing.allocator, mat2);
+    defer mat3.deinit();
+
+    try std.testing.expect(mat3.numbers[0] == 3);
+    try std.testing.expect(mat3.numbers[1] == 3);
+    try std.testing.expect(mat3.numbers[2] == 3);
+    try std.testing.expect(mat3.numbers[3] == 3);
+}
+
+test "matrix sub" {
+    const mat1 = try Matrix.init(std.testing.allocator, &[_]u64{ 2, 2 });
+    defer mat1.deinit();
+    const mat2 = try Matrix.init(std.testing.allocator, &[_]u64{ 2, 2 });
+    defer mat2.deinit();
+
+    mat1.fill(1);
+    mat2.fill(2);
+
+    const mat3 = try mat1.sub(std.testing.allocator, mat2);
+    defer mat3.deinit();
+
+    try std.testing.expect(mat3.numbers[0] == -1);
+    try std.testing.expect(mat3.numbers[1] == -1);
+    try std.testing.expect(mat3.numbers[2] == -1);
+    try std.testing.expect(mat3.numbers[3] == -1);
+}