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Percolation/Site percolation: Difference between revisions
→{{header|Go}}: Add Go
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(→{{header|Go}}: Add Go) |
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end program percolation_site
</lang>
=={{header|Go}}==
<lang go>package main
import (
"bytes"
"fmt"
"math/rand"
"time"
)
func main() {
const (
m, n = 15, 15
t = 1e4
minp, maxp, Δp = 0, 1, 0.1
)
rand.Seed(2) // Fixed seed for repeatable example grid
g := NewGrid(.5, m, n)
g.Percolate()
fmt.Println(g)
rand.Seed(time.Now().UnixNano()) // could pick a better seed
for p := float64(minp); p < maxp; p += Δp {
count := 0
for i := 0; i < t; i++ {
g := NewGrid(p, m, n)
if g.Percolate() {
count++
}
}
fmt.Printf("p=%.2f, %.4f\n", p, float64(count)/t)
}
}
const (
full = '.'
used = '#'
empty = ' '
)
type grid struct {
cell [][]byte // row first, i.e. [y][x]
}
func NewGrid(p float64, xsize, ysize int) *grid {
g := &grid{cell: make([][]byte, ysize)}
for y := range g.cell {
g.cell[y] = make([]byte, xsize)
for x := range g.cell[y] {
if rand.Float64() < p {
g.cell[y][x] = full
} else {
g.cell[y][x] = empty
}
}
}
return g
}
func (g *grid) String() string {
var buf bytes.Buffer
// Don't really need to call Grow but it helps avoid multiple
// reallocations if the size is large.
buf.Grow((len(g.cell) + 2) * (len(g.cell[0]) + 3))
buf.WriteByte('+')
for _ = range g.cell[0] {
buf.WriteByte('-')
}
buf.WriteString("+\n")
for y := range g.cell {
buf.WriteByte('|')
buf.Write(g.cell[y])
buf.WriteString("|\n")
}
buf.WriteByte('+')
ly := len(g.cell) - 1
for x := range g.cell[ly] {
if g.cell[ly][x] == used {
buf.WriteByte(used)
} else {
buf.WriteByte('-')
}
}
buf.WriteByte('+')
return buf.String()
}
func (g *grid) Percolate() bool {
for x := range g.cell[0] {
if g.use(x, 0) {
return true
}
}
return false
}
func (g *grid) use(x, y int) bool {
if y < 0 || x < 0 || x >= len(g.cell[0]) || g.cell[y][x] != full {
return false // Off the edges, empty, or used
}
g.cell[y][x] = used
if y+1 == len(g.cell) {
return true // We're on the bottom
}
// Try down, right, left, up in that order.
return g.use(x, y+1) ||
g.use(x+1, y) ||
g.use(x-1, y) ||
g.use(x, y-1)
}</lang>
{{out}}
<pre>+---------------+
|#### ###. .. |
| ## # # . .|
| ### #### .. |
|### ##### #.. |
| ### # ## .. |
|# ## # . ..|
|### . #.. . |
| ## ##. ..|
| ## .. .. # .. |
| ## . .#....|
|## .. .## . |
|# . . . # . |
| .. . .#. .. |
|. . .... # .. |
| . .. . # .. .|
+---------#-----+
p=0.00, 0.0000
p=0.10, 0.0000
p=0.20, 0.0000
p=0.30, 0.0000
p=0.40, 0.0040
p=0.50, 0.0980
p=0.60, 0.5641
p=0.70, 0.9583
p=0.80, 0.9995
p=0.90, 1.0000
p=1.00, 1.0000
</pre>
=={{header|J}}==
| |||