FillStateTable()

diff --git a/planeteer.go b/planeteer.go
index 314a3b62e62c18a4a8a7f259c33df374ffe6214b..456e6b3cade3a64522a14b1cdd287c50b52b0633 100644 (file)
--- a/planeteer.go
+++ b/planeteer.go
@@ -70,7 +70,8 @@ type Planet struct {
 type planet_data struct {
        Commodities map[string]Commodity
        Planets     map[string]Planet
 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) {
 }
 
 func ReadData() (data planet_data) {


@@ -104,6 +105,15 @@ 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.
  * 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:
  */
 
 // The official list of dimensions:


@@ -164,10 +174,6 @@ type State struct {
        funds, from int
 }
 
        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++ {
 func EncodeIndex(dims, addr []int) int {
        index := addr[0]
        for i := 1; i < len(dims); i++ {


@@ -186,6 +192,96 @@ func DecodeIndex(dims []int, index int) []int {
        return addr
 }
 
        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,
 /* 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,


@@ -221,7 +317,7 @@ func FindBestTrades(data planet_data) [][]string {
        // 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 {
        // 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
                for to := range data.Planets {
                        best_gain := 0
                        price_list := data.Planets[from].RelativePrices


@@ -236,7 +332,7 @@ func FindBestTrades(data planet_data) [][]string {
                                        10000000,
                                        1)
                                if gain > best_gain {
                                        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
                                }
                        }
                                        gain = best_gain
                                }
                        }


@@ -246,40 +342,44 @@ func FindBestTrades(data planet_data) [][]string {
 }
 
 // (Example of a use case for generics in Go)
 }
 
 // (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 {
        for e := range *m {

-               index[e] = i
+               e2i[e] = i
+               i2e[i] = e

                i++
        }
                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 {
        for e := range *m {

-               index[e] = i
+               e2i[e] = i
+               i2e[i] = e

                i++
        }
                i++
        }

-       return index
+       return e2i, i2e

 }
 
 func main() {
        flag.Parse()
        data := ReadData()
 }
 
 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)
        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)"
        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)
                }
                        }
                        fmt.Printf("%s to %s: %s\n", from, to, best_trade)
                }