more performance tests

various-tests/perf-1dim/main.go

@@ -0,0 +1,106 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"math/rand"
+	"os"
+	"runtime/pprof"
+	"unsafe"
+)
+
+const (
+	dim     int  = 1500
+	loops   int  = 5000
+	density int  = 8
+	debug   bool = false
+)
+
+var max int
+
+// https://dev.to/chigbeef_77/bool-int-but-stupid-in-go-3jb3
+func bool2int(b bool) int {
+	return int(*(*byte)(unsafe.Pointer(&b)))
+}
+
+func Count(grid []bool, x, y int) int {
+	var sum int
+
+	for nbgX := -1; nbgX < 2; nbgX++ {
+		for nbgY := -1; nbgY < 2; nbgY++ {
+			var col, row int
+
+			if x+nbgX < 0 || x+nbgX >= dim || y+nbgY < 0 || y+nbgY >= dim {
+				continue
+			}
+
+			col = x + nbgX
+			row = y + nbgY
+
+			state := grid[row*col]
+			intstate := bool2int(state)
+			sum += intstate
+		}
+	}
+
+	sum -= bool2int(grid[y*x])
+
+	return sum
+}
+
+func Init() []bool {
+	max = dim * dim
+
+	grid := make([]bool, max)
+
+	for y := 0; y < dim; y++ {
+		for x := 0; x < dim; x++ {
+			if rand.Intn(density) == 1 {
+				grid[y*x] = true
+			}
+		}
+	}
+
+	return grid
+}
+
+func Loop(grid []bool) {
+	c := 0
+	for i := 0; i < loops; i++ {
+		for y := 0; y < dim; y++ {
+			for x := 0; x < dim; x++ {
+				state := grid[y*x]
+				neighbors := Count(grid, x, y)
+				if state && neighbors > 1 {
+					if debug {
+						fmt.Printf("Loop %d - cell at %d,%d is %t and has %d living neighbors\n", i, x, y, state, neighbors)
+					}
+					c = 1
+				}
+			}
+		}
+	}
+
+	if c > 1 {
+		c = 0
+	}
+}
+
+func main() {
+	// enable  cpu profiling. Do  NOT use q  to stop the  game but
+	// close the window to get a profile
+	fd, err := os.Create("cpu.profile")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer fd.Close()
+
+	pprof.StartCPUProfile(fd)
+	defer pprof.StopCPUProfile()
+
+	// init
+	grid := Init()
+
+	// main loop
+	Loop(grid)
+}