type planet_data struct {
Commodities map[string]Commodity
Planets map[string]Planet
- pi, ci map[string]int // Generated; not read from file
+ p2i, c2i map[string]int // Generated; not read from file
+ i2p, i2c []string // Generated; not read from file
}
func ReadData() (data planet_data) {
* Note that the sizes of each dimension are data driven. Many dimensions
* collapse to one possible value (ie, disappear) if the corresponding
* feature is not enabled.
+ *
+ * The order of the dimensions in the list of constants below determines
+ * their layout in RAM. The cargo-based 'dimensions' are not completely
+ * independent -- some combinations are illegal and not used. They are
+ * handled as three dimensions rather than one for simplicity. Placing
+ * these dimensions first causes the unused cells in the table to be
+ * grouped together in large blocks. This keeps them from polluting
+ * cache lines, and if they are large enough, prevent the memory manager
+ * from allocating pages for these areas at all.
*/
// The official list of dimensions:
dims[NeedFighters] = bint(*drones > 0) + 1
dims[NeedShields] = bint(*batteries > 0) + 1
dims[Visit] = 1 << uint(len(visit()))
+
+ // Remind myself to add a line above when adding new dimensions
+ for i, dim := range dims {
+ if dim < 1 {
+ panic(i)
+ }
+ }
return dims
}
funds, from int
}
-func NewStateTable(dims []int) []State {
- return make([]State, StateTableSize(dims))
-}
-
func EncodeIndex(dims, addr []int) int {
index := addr[0]
for i := 1; i < len(dims); i++ {
return addr
}
+func FillStateCell(data planet_data, dims []int, table []State, addr []int) {
+}
+
+func FillStateTable2(data planet_data, dims []int, table []State,
+fuel_remaining, edens_remaining int, planet string, barrier chan<- bool) {
+ /* The dimension nesting order up to this point is important.
+ * Beyond this point, it's not important.
+ *
+ * It is very important when iterating through the Hold dimension
+ * to visit the null commodity (empty hold) first. Visiting the
+ * null commodity represents selling. Visiting it first gets the
+ * action order correct: arrive, sell, buy, leave. Visiting the
+ * null commodity after another commodity would evaluate the action
+ * sequence: arrive, buy, sell, leave. This is a useless action
+ * sequence. Because we visit the null commodity first, we do not
+ * consider these action sequences.
+ */
+ eden_capacity := data.Commodities["Eden Warp Units"].Limit
+ addr := make([]int, len(dims))
+ addr[Edens] = edens_remaining
+ addr[Fuel] = fuel_remaining
+ addr[Location] = data.p2i[planet]
+ for addr[Hold] = 0; addr[Hold] < dims[Hold]; addr[Hold]++ {
+ for addr[Cloaks] = 0; addr[Cloaks] < dims[Cloaks]; addr[Cloaks]++ {
+ for addr[UnusedCargo] = 0;
+ addr[UnusedCargo] < dims[UnusedCargo];
+ addr[UnusedCargo]++ {
+ if addr[Edens] + addr[Cloaks] + addr[UnusedCargo] <=
+ eden_capacity + 1 {
+ for addr[NeedFighters] = 0;
+ addr[NeedFighters] < dims[NeedFighters];
+ addr[NeedFighters]++ {
+ for addr[NeedShields] = 0;
+ addr[NeedShields] < dims[NeedShields];
+ addr[NeedShields]++ {
+ for addr[Visit] = 0;
+ addr[Visit] < dims[Visit];
+ addr[Visit]++ {
+ FillStateCell(data, dims, table, addr)
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ barrier <- true
+}
+
+/* Filling the state table is a set of nested for loops NumDimensions deep.
+ * We split this into two procedures: 1 and 2. #1 is the outer, slowest-
+ * changing indexes. #1 fires off many calls to #2 that run in parallel.
+ * The order of the nesting of the dimensions, the order of iteration within
+ * each dimension, and where the 1 / 2 split is placed are carefully chosen
+ * to make this arrangement safe.
+ *
+ * Outermost two layers: Go from high-energy states (lots of fuel, edens) to
+ * low-energy state. These must be processed sequentially and in this order
+ * because you travel through high-energy states to get to the low-energy
+ * states.
+ *
+ * Third layer: Planet. This is a good layer to parallelize on. There's
+ * high enough cardinality that we don't have to mess with parallelizing
+ * multiple layers for good utilization (on 2011 machines). Each thread
+ * works on one planet's states and need not synchronize with peer threads.
+ */
+func FillStateTable1(data planet_data, dims []int) []State {
+ table := make([]State, StateTableSize(dims))
+ barrier := make(chan bool, len(data.Planets))
+ eden_capacity := data.Commodities["Eden Warp Units"].Limit
+ work_units := (float64(*fuel) + 1) * (float64(eden_capacity) + 1)
+ work_done := 0.0
+ for fuel_remaining := *fuel; fuel_remaining >= 0; fuel_remaining-- {
+ for edens_remaining := eden_capacity;
+ edens_remaining >= 0;
+ edens_remaining-- {
+ for planet := range data.Planets {
+ go FillStateTable2(data, dims, table, fuel_remaining,
+ edens_remaining, planet, barrier)
+ }
+ for _ = range data.Planets {
+ <-barrier
+ }
+ work_done++
+ fmt.Printf("\r%3.0f%%", 100 * work_done / work_units)
+ }
+ }
+ return table
+}
+
/* What is the value of hauling 'commodity' from 'from' to 'to'?
* Take into account the available funds and the available cargo space. */
func TradeValue(data planet_data,
// TODO: We can't cache this because this can change based on available funds.
best := make([][]string, len(data.Planets))
for from := range data.Planets {
- best[data.pi[from]] = make([]string, len(data.Planets))
+ best[data.p2i[from]] = make([]string, len(data.Planets))
for to := range data.Planets {
best_gain := 0
price_list := data.Planets[from].RelativePrices
10000000,
1)
if gain > best_gain {
- best[data.pi[from]][data.pi[to]] = commodity
+ best[data.p2i[from]][data.p2i[to]] = commodity
gain = best_gain
}
}
}
// (Example of a use case for generics in Go)
-func IndexPlanets(m *map[string]Planet) map[string]int {
- index := make(map[string]int, len(*m))
- i := 0
+func IndexPlanets(m *map[string]Planet, start_at int) (map[string]int, []string) {
+ e2i := make(map[string]int, len(*m) + start_at)
+ i2e := make([]string, len(*m) + start_at)
+ i := start_at
for e := range *m {
- index[e] = i
+ e2i[e] = i
+ i2e[i] = e
i++
}
- return index
+ return e2i, i2e
}
-func IndexCommodities(m *map[string]Commodity) map[string]int {
- index := make(map[string]int, len(*m))
- i := 0
+func IndexCommodities(m *map[string]Commodity, start_at int) (map[string]int, []string) {
+ e2i := make(map[string]int, len(*m) + start_at)
+ i2e := make([]string, len(*m) + start_at)
+ i := start_at
for e := range *m {
- index[e] = i
+ e2i[e] = i
+ i2e[i] = e
i++
}
- return index
+ return e2i, i2e
}
func main() {
flag.Parse()
data := ReadData()
- data.pi = IndexPlanets(&data.Planets)
- data.ci = IndexCommodities(&data.Commodities)
+ data.p2i, data.i2p = IndexPlanets(&data.Planets, 0)
+ data.c2i, data.i2c = IndexCommodities(&data.Commodities, 1)
dims := DimensionSizes(data)
- table := NewStateTable(dims)
+ table := FillStateTable1(data, dims)
table[0] = State{1, 1}
best_trades := FindBestTrades(data)
for from := range data.Planets {
for to := range data.Planets {
best_trade := "(nothing)"
- if best_trades[data.pi[from]][data.pi[to]] != "" {
- best_trade = best_trades[data.pi[from]][data.pi[to]]
+ if best_trades[data.p2i[from]][data.p2i[to]] != "" {
+ best_trade = best_trades[data.p2i[from]][data.p2i[to]]
}
fmt.Printf("%s to %s: %s\n", from, to, best_trade)
}
projects / planeteer / blobdiff