From d79befe12a8d6b32a41beb88d6e75b12a75615a7 Mon Sep 17 00:00:00 2001
From: Tom Barrett <tom@tombarrett.xyz>
Date: Wed, 30 Jun 2021 17:19:47 +0200
Subject: rotating cube

---
 src/matrix.zig | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 src/matrix.zig

(limited to 'src/matrix.zig')

diff --git a/src/matrix.zig b/src/matrix.zig
new file mode 100644
index 0000000..eaf9685
--- /dev/null
+++ b/src/matrix.zig
@@ -0,0 +1,54 @@
+const std = @import("std");
+const ArrayList = std.ArrayList;
+
+const matrix = struct {
+    h: usize,
+    w: usize,
+    x: ArrayList(f32),
+};
+
+pub fn new(h: usize, w: usize, x: []f32) matrix {
+    var m = matrix{
+        .h = h,
+        .w = w,
+        .x = ArrayList(f32).init(std.heap.page_allocator),
+    };
+
+    var i: usize = 0;
+    while (i < h * w) : (i += 1) {
+        if (m.x.append(x[i])) |val| {} else |err| {}
+    }
+
+    return m;
+}
+
+pub fn dot(a: []f32, b: []f32, len: usize, step: usize) f32 {
+    var x: f32 = 0;
+    var j: usize = 0;
+    var i: usize = len;
+    var k: usize = 0;
+
+    while (i > 0) : (i -= 1) {
+        x += a[k] * b[j];
+        k += 1;
+        j += step;
+    }
+
+    return x;
+}
+
+pub fn multiply(a: matrix, b: matrix) matrix {
+    var x = ArrayList(f32).init(std.heap.page_allocator);
+    var i: usize = 0;
+    var k: usize = 0;
+
+    while (i < a.h) : (i += 1) {
+        var j: usize = 0;
+        while (j < b.w) : (j += 1) {
+            if (x.append(dot(a.x.items[k..], b.x.items[j..], a.w, b.w))) |val| {} else |err| {}
+        }
+        k += a.w;
+    }
+
+    return new(a.h, b.w, x.items);
+}
-- 
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