Don't use 0 for uninitialized indexes

[planeteer] / planeteer.go

diff --git a/planeteer.go b/planeteer.go
index 5acf98fd87b3179ec9e1638c7096052f6229dbef..e3c04cfb3bd9690bbd5e465605240b788b34c6fc 100644 (file)
--- a/planeteer.go
+++ b/planeteer.go
@@ -21,18 +21,25 @@ import "flag"
 import "fmt"
 import "json"
 import "os"
 import "fmt"
 import "json"
 import "os"

+import "runtime/pprof"

 import "strings"
 
 import "strings"
 

+var funds = flag.Int("funds", 0,
+       "Starting funds")
+

 var start = flag.String("start", "",
        "The planet to start at")
 
 var start = flag.String("start", "",
        "The planet to start at")
 

-var end = flag.String("end", "",
+var flight_plan_string = flag.String("flight_plan", "",
+       "Your hyper-holes for the day, comma-separated.")
+
+var end_string = flag.String("end", "",

        "A comma-separated list of acceptable ending planets.")
 
 var planet_data_file = flag.String("planet_data_file", "planet-data",
        "The file to read planet data from")
 
        "A comma-separated list of acceptable ending planets.")
 
 var planet_data_file = flag.String("planet_data_file", "planet-data",
        "The file to read planet data from")
 

-var fuel = flag.Int("fuel", 16, "Reactor units")
+var fuel = flag.Int("fuel", 16, "Hyper Jump power left")

 
 var hold = flag.Int("hold", 300, "Size of your cargo hold")
 
 
 var hold = flag.Int("hold", 300, "Size of your cargo hold")
 


@@ -49,11 +56,53 @@ var drones = flag.Int("drones", 0, "Buy this many Fighter Drones")
 
 var batteries = flag.Int("batteries", 0, "Buy this many Shield Batterys")
 
 
 var batteries = flag.Int("batteries", 0, "Buy this many Shield Batterys")
 

+var drone_price = flag.Int("drone_price", 0, "Today's Fighter Drone price")
+
+var battery_price = flag.Int("battery_price", 0, "Today's Shield Battery price")
+

 var visit_string = flag.String("visit", "",
        "A comma-separated list of planets to make sure to visit")
 
 var visit_string = flag.String("visit", "",
        "A comma-separated list of planets to make sure to visit")
 

+var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
+
+var visit_cache []string
+

 func visit() []string {
 func visit() []string {

-       return strings.Split(*visit_string, ",")
+       if visit_cache == nil {
+               if *visit_string == "" {
+                       return nil
+               }
+               visit_cache = strings.Split(*visit_string, ",")
+       }
+       return visit_cache
+}
+
+var flight_plan_cache []string
+
+func flight_plan() []string {
+       if flight_plan_cache == nil {
+               if *flight_plan_string == "" {
+                       return nil
+               }
+               flight_plan_cache = strings.Split(*flight_plan_string, ",")
+       }
+       return flight_plan_cache
+}
+
+var end_cache map[string]bool
+
+func end() map[string]bool {
+       if end_cache == nil {
+               if *end_string == "" {
+                       return nil
+               }
+               m := make(map[string]bool)
+               for _, p := range strings.Split(*end_string, ",") {
+                       m[p] = true
+               }
+               end_cache = m
+       }
+       return end_cache

 }
 
 type Commodity struct {
 }
 
 type Commodity struct {


@@ -63,6 +112,7 @@ type Commodity struct {
 }
 type Planet struct {
        BeaconOn bool
 }
 type Planet struct {
        BeaconOn bool

+       Private  bool

        /* Use relative prices rather than absolute prices because you
           can get relative prices without traveling to each planet. */
        RelativePrices map[string]int
        /* Use relative prices rather than absolute prices because you
           can get relative prices without traveling to each planet. */
        RelativePrices map[string]int


@@ -70,7 +120,8 @@ 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) {


@@ -104,20 +155,41 @@ 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, allows the memory manager
+ * to swap out entire pages.
+ *
+ * If the table gets too big to fit in RAM:
+ *    * Combine the Edens, Cloaks, and UnusedCargo dimensions.  Of the
+ *      24 combinations, only 15 are legal: a 38% savings.
+ *    * Reduce the size of the Fuel dimension to 3.  We only ever look
+ *      backwards 2 units, so just rotate the logical values through
+ *      the same 3 physical addresses.  This is good for an 82% savings.
+ *    * Reduce the size of the Edens dimension from 3 to 2, for the
+ *      same reasons as Fuel above.  33% savings.
+ *    * Buy more ram.  (Just sayin'.  It's cheaper than you think.)
+ *      

  */
 
 // The official list of dimensions:
 const (
  */
 
 // The official list of dimensions:
 const (

-       // Name                Num  Size  Description
-       Edens        = iota //   1     3  # of Eden warp units (0 - 2 typically)
-       Cloaks              //   2     2  # of Devices of Cloaking (0 or 1)
-       UnusedCargo         //   3     4  # of unused cargo spaces (0 - 3 typically)
-       Fuel                //   4    17  Reactor power left (0 - 16)
-       Location            //   5    26  Location (which planet)
-       Hold                //   6    15  Cargo bay contents (a *Commodity or nil)
-       NeedFighters        //   7     2  Errand: Buy fighter drones (needed or not)
-       NeedShields         //   8     2  Errand: Buy shield batteries (needed or not)
-       Visit               //   9  2**N  Visit: Stop by these N planets in the route
+       // Name                Num   Size  Description
+       Edens       = iota //   1      3  # of Eden warp units (0 - 2 typically)
+       Cloaks             //   2    1-2  # of Devices of Cloaking (0 or 1)
+       UnusedCargo        //   3      4  # of unused cargo spaces (0 - 3 typically)
+       Fuel               //   4     17  Hyper jump power left (0 - 16)
+       Location           //   5     26  Location (which planet)
+       Hold               //   6     15  Cargo bay contents (a *Commodity or nil)
+       Traded             //   7      2  Traded yet?
+       BuyFighters        //   8    1-2  Errand: Buy fighter drones
+       BuyShields         //   9    1-2  Errand: Buy shield batteries
+       Visit              //  10 1-2**N  Visit: Stop by these N planets in the route

 
        NumDimensions
 )
 
        NumDimensions
 )


@@ -131,6 +203,9 @@ func bint(b bool) int {
 
 func DimensionSizes(data planet_data) []int {
        eden_capacity := data.Commodities["Eden Warp Units"].Limit
 
 func DimensionSizes(data planet_data) []int {
        eden_capacity := data.Commodities["Eden Warp Units"].Limit

+       if *start_edens > eden_capacity {
+               eden_capacity = *start_edens
+       }

        cloak_capacity := bint(*cloak)
        dims := make([]int, NumDimensions)
        dims[Edens] = eden_capacity + 1
        cloak_capacity := bint(*cloak)
        dims := make([]int, NumDimensions)
        dims[Edens] = eden_capacity + 1


@@ -138,143 +213,484 @@ func DimensionSizes(data planet_data) []int {
        dims[UnusedCargo] = eden_capacity + cloak_capacity + 1
        dims[Fuel] = *fuel + 1
        dims[Location] = len(data.Planets)
        dims[UnusedCargo] = eden_capacity + cloak_capacity + 1
        dims[Fuel] = *fuel + 1
        dims[Location] = len(data.Planets)

-       dims[Hold] = len(data.Commodities)
-       dims[NeedFighters] = bint(*drones > 0) + 1
-       dims[NeedShields] = bint(*batteries > 0) + 1
+       dims[Hold] = len(data.Commodities) + 1
+       dims[Traded] = 2
+       dims[BuyFighters] = bint(*drones > 0) + 1
+       dims[BuyShields] = bint(*batteries > 0) + 1

        dims[Visit] = 1 << uint(len(visit()))
        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
 }
 
 func StateTableSize(dims []int) int {
        return dims
 }
 
 func StateTableSize(dims []int) int {

-       sum := 0
+       product := 1

        for _, size := range dims {
        for _, size := range dims {

-               sum += size
+               product *= size

        }
        }

-       return sum
+       return product

 }
 
 type State struct {
 }
 
 type State struct {

-       funds, from int
+       value, from int32

 }
 
 }
 

-func NewStateTable(dims []int) []State {
-       return make([]State, StateTableSize(dims))
-}
+const (
+       FROM_ROOT = -2147483647 + iota
+       FROM_UNINITIALIZED
+       VALUE_UNINITIALIZED
+       VALUE_BEING_EVALUATED
+       VALUE_RUBISH
+)

 
 

-func EncodeIndex(dims, addr []int) int {
+func EncodeIndex(dims, addr []int) int32 {

        index := addr[0]
        index := addr[0]

-       for i := 1; i < len(dims); i++ {
+       if addr[0] > dims[0] {
+               panic(0)
+       }
+       for i := 1; i < NumDimensions; i++ {
+               if addr[i] < 0 || addr[i] >= dims[i] {
+                       panic(i)
+               }

                index = index*dims[i] + addr[i]
        }
                index = index*dims[i] + addr[i]
        }

-       return index
+       return int32(index)

 }
 
 }
 

-func DecodeIndex(dims []int, index int) []int {
-       addr := make([]int, len(dims))
-       for i := len(dims) - 1; i > 0; i-- {
-               addr[i] = index % dims[i]
-               index /= dims[i]
+func DecodeIndex(dims []int, index int32) []int {
+       addr := make([]int, NumDimensions)
+       for i := NumDimensions - 1; i > 0; i-- {
+               addr[i] = int(index) % dims[i]
+               index /= int32(dims[i])

        }
        }

-       addr[0] = index
+       addr[0] = int(index)

        return addr
 }
 
        return addr
 }
 

-/* 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,
-from, to Planet,
-commodity string,
-initial_funds, max_quantity int) int {
-       if !data.Commodities[commodity].CanSell {
-               return 0
-       }
-       from_relative_price, from_available := from.RelativePrices[commodity]
-       if !from_available {
-               return 0
-       }
-       to_relative_price, to_available := to.RelativePrices[commodity]
-       if !to_available {
-               return 0
-       }
-
-       base_price := data.Commodities[commodity].BasePrice
-       from_absolute_price := from_relative_price * base_price
-       to_absolute_price := to_relative_price * base_price
-       buy_price := from_absolute_price
-       sell_price := int(float64(to_absolute_price) * 0.9)
-       var can_afford int = initial_funds / buy_price
-       quantity := can_afford
-       if quantity > max_quantity {
-               quantity = max_quantity
-       }
-       return (sell_price - buy_price) * max_quantity
+func CreateStateTable(data planet_data, dims []int) []State {
+       table := make([]State, StateTableSize(dims))
+       for i := range table {
+               table[i].value = VALUE_UNINITIALIZED
+               table[i].from = FROM_UNINITIALIZED
+       }
+
+       addr := make([]int, NumDimensions)
+       addr[Fuel] = *fuel
+       addr[Edens] = *start_edens
+       addr[Location] = data.p2i[*start]
+       addr[Traded] = 1
+       start_index := EncodeIndex(dims, addr)
+       table[start_index].value = int32(*funds)
+       table[start_index].from = FROM_ROOT
+
+       return table
+}
+
+/* CellValue fills in the one cell at address addr by looking at all
+ * the possible ways to reach this cell and selecting the best one. */
+
+func Consider(data planet_data, dims []int, table []State, there []int, value_difference int, best_value *int32, best_source []int) {
+       there_value := CellValue(data, dims, table, there)
+       if value_difference < 0 && int32(-value_difference) > there_value {
+               /* Can't afford this transition */
+               return
+       }
+       possible_value := there_value + int32(value_difference)
+       if possible_value > *best_value {
+               *best_value = possible_value
+               copy(best_source, there)
+       }

 }
 
 }
 

-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 {
-               best[data.pi[from]] = make([]string, len(data.Planets))
-               for to := range data.Planets {
-                       best_gain := 0
-                       price_list := data.Planets[from].RelativePrices
-                       if len(data.Planets[to].RelativePrices) < len(data.Planets[from].RelativePrices) {
-                               price_list = data.Planets[to].RelativePrices
+var cell_filled_count int
+
+func CellValue(data planet_data, dims []int, table []State, addr []int) int32 {
+       my_index := EncodeIndex(dims, addr)
+       if table[my_index].value == VALUE_BEING_EVALUATED {
+               panic("Circular dependency")
+       }
+       if table[my_index].value != VALUE_UNINITIALIZED {
+               return table[my_index].value
+       }
+       table[my_index].value = VALUE_BEING_EVALUATED
+
+       best_value := int32(VALUE_RUBISH)
+       best_source := make([]int, NumDimensions)
+       other := make([]int, NumDimensions)
+       copy(other, addr)
+       planet := data.i2p[addr[Location]]
+
+       /* Travel here */
+       if addr[Traded] == 0 { /* Can't have traded immediately after traveling. */
+               other[Traded] = 1 /* Travel from states that have done trading. */
+
+               /* Travel here via a 2-fuel unit jump */
+               if addr[Fuel]+2 < dims[Fuel] {
+                       other[Fuel] = addr[Fuel] + 2
+                       hole_index := (dims[Fuel] - 1) - (addr[Fuel] + 2)
+                       if hole_index >= len(flight_plan()) || addr[Location] != data.p2i[flight_plan()[hole_index]] {
+                               for other[Location] = 0; other[Location] < dims[Location]; other[Location]++ {
+                                       if data.Planets[data.i2p[addr[Location]]].BeaconOn {
+                                               Consider(data, dims, table, other, 0, &best_value, best_source)
+                                       }
+                               }
+                       }
+                       other[Location] = addr[Location]
+                       other[Fuel] = addr[Fuel]
+               }
+
+               /* Travel here via a 1-fuel unit jump (a hyper hole) */
+               if addr[Fuel]+1 < dims[Fuel] {
+                       hole_index := (dims[Fuel] - 1) - (addr[Fuel] + 1)
+                       if hole_index < len(flight_plan()) && addr[Location] == data.p2i[flight_plan()[hole_index]] {
+                               other[Fuel] = addr[Fuel] + 1
+                               for other[Location] = 0; other[Location] < dims[Location]; other[Location]++ {
+                                       Consider(data, dims, table, other, 0, &best_value, best_source)
+                               }
+                               other[Location] = addr[Location]
+                               other[Fuel] = addr[Fuel]
+                       }
+               }
+
+               /* Travel here via Eden Warp Unit */
+               if addr[Edens]+1 < dims[Edens] && addr[UnusedCargo] > 0 {
+                       _, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Eden Warp Units"]
+                       if !available {
+                               other[Edens] = addr[Edens] + 1
+                               if other[Hold] != 0 {
+                                       other[UnusedCargo] = addr[UnusedCargo] - 1
+                               }
+                               for other[Location] = 0; other[Location] < dims[Location]; other[Location]++ {
+                                       Consider(data, dims, table, other, 0, &best_value, best_source)
+                               }
+                               other[Location] = addr[Location]
+                               other[UnusedCargo] = addr[UnusedCargo]
+                               other[Edens] = addr[Edens]
+                       }
+               }
+               other[Traded] = addr[Traded]
+       }
+
+       /* Trade */
+       if addr[Traded] == 1 {
+               other[Traded] = 0
+
+               /* Consider not trading */
+               Consider(data, dims, table, other, 0, &best_value, best_source)
+
+               if !data.Planets[data.i2p[addr[Location]]].Private {
+
+                       /* Sell */
+                       if addr[Hold] == 0 && addr[UnusedCargo] == 0 {
+                               for other[Hold] = 0; other[Hold] < dims[Hold]; other[Hold]++ {
+                                       commodity := data.i2c[other[Hold]]
+                                       if !data.Commodities[commodity].CanSell {
+                                               continue
+                                       }
+                                       relative_price, available := data.Planets[planet].RelativePrices[commodity]
+                                       if !available {
+                                               // TODO: Dump cargo
+                                               continue
+                                       }
+                                       base_price := data.Commodities[commodity].BasePrice
+                                       absolute_price := float64(base_price) * float64(relative_price) / 100.0
+                                       sell_price := int(absolute_price * 0.9)
+
+                                       for other[UnusedCargo] = 0; other[UnusedCargo] < dims[UnusedCargo]; other[UnusedCargo]++ {
+                                               quantity := *hold - (other[UnusedCargo] + other[Cloaks] + other[Edens])
+                                               sale_value := quantity * sell_price
+                                               Consider(data, dims, table, other, sale_value, &best_value, best_source)
+                                       }
+                               }
+                               other[UnusedCargo] = addr[UnusedCargo]
+                               other[Hold] = addr[Hold]
+                       }
+
+                       /* Buy */
+                       other[Traded] = addr[Traded] /* Buy after selling */
+                       if addr[Hold] != 0 {
+                               commodity := data.i2c[addr[Hold]]
+                               if data.Commodities[commodity].CanSell {
+                                       relative_price, available := data.Planets[planet].RelativePrices[commodity]
+                                       if available {
+                                               base_price := data.Commodities[commodity].BasePrice
+                                               absolute_price := int(float64(base_price) * float64(relative_price) / 100.0)
+                                               quantity := *hold - (addr[UnusedCargo] + addr[Cloaks] + addr[Edens])
+                                               total_price := quantity * absolute_price
+                                               other[Hold] = 0
+                                               other[UnusedCargo] = 0
+                                               Consider(data, dims, table, other, -total_price, &best_value, best_source)
+                                               other[UnusedCargo] = addr[UnusedCargo]
+                                               other[Hold] = addr[Hold]
+                                       }
+                               }
+                       }
+               }
+               other[Traded] = addr[Traded]
+       }
+
+       /* Buy a Device of Cloaking */
+       if addr[Cloaks] == 1 && addr[UnusedCargo] < dims[UnusedCargo]-1 {
+               relative_price, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Device Of Cloakings"]
+               if available {
+                       absolute_price := int(float64(data.Commodities["Device Of Cloakings"].BasePrice) * float64(relative_price) / 100.0)
+                       other[Cloaks] = 0
+                       if other[Hold] != 0 {
+                               other[UnusedCargo] = addr[UnusedCargo] + 1

                        }
                        }

-                       for commodity := range price_list {
-                               gain := TradeValue(data,
-                                       data.Planets[from],
-                                       data.Planets[to],
-                                       commodity,
-                                       10000000,
-                                       1)
-                               if gain > best_gain {
-                                       best[data.pi[from]][data.pi[to]] = commodity
-                                       gain = best_gain
+                       Consider(data, dims, table, other, -absolute_price, &best_value, best_source)
+                       other[UnusedCargo] = addr[UnusedCargo]
+                       other[Cloaks] = addr[Cloaks]
+               }
+       }
+
+       /* Buy Fighter Drones */
+       if addr[BuyFighters] == 1 {
+               relative_price, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Fighter Drones"]
+               if available {
+                       absolute_price := int(float64(data.Commodities["Fighter Drones"].BasePrice) * float64(relative_price) / 100.0)
+                       other[BuyFighters] = 0
+                       Consider(data, dims, table, other, -absolute_price**drones, &best_value, best_source)
+                       other[BuyFighters] = addr[BuyFighters]
+               }
+       }
+
+       /* Buy Shield Batteries */
+       if addr[BuyShields] == 1 {
+               relative_price, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Shield Batterys"]
+               if available {
+                       absolute_price := int(float64(data.Commodities["Shield Batterys"].BasePrice) * float64(relative_price) / 100.0)
+                       other[BuyShields] = 0
+                       Consider(data, dims, table, other, -absolute_price**batteries, &best_value, best_source)
+                       other[BuyShields] = addr[BuyShields]
+               }
+       }
+
+       /* Visit this planet */
+       var i uint
+       for i = 0; i < uint(len(visit())); i++ {
+               if addr[Visit]&(1<<i) != 0 && visit()[i] == data.i2p[addr[Location]] {
+                       other[Visit] = addr[Visit] & ^(1 << i)
+                       Consider(data, dims, table, other, 0, &best_value, best_source)
+               }
+       }
+       other[Visit] = addr[Visit]
+
+       /* Buy Eden warp units */
+       eden_limit := data.Commodities["Eden Warp Units"].Limit
+       if addr[Edens] > 0 && addr[Edens] <= eden_limit {
+               relative_price, available := data.Planets[data.i2p[addr[Location]]].RelativePrices["Eden Warp Units"]
+               if available {
+                       absolute_price := int(float64(data.Commodities["Eden Warp Units"].BasePrice) * float64(relative_price) / 100.0)
+                       for quantity := addr[Edens]; quantity > 0; quantity-- {
+                               other[Edens] = addr[Edens] - quantity
+                               if addr[Hold] != 0 {
+                                       other[UnusedCargo] = addr[UnusedCargo] + quantity
+                               }
+                               if other[UnusedCargo] < dims[UnusedCargo] {
+                                       Consider(data, dims, table, other, -absolute_price*quantity, &best_value, best_source)

                                }
                        }
                                }
                        }

+                       other[Edens] = addr[Edens]
+                       other[UnusedCargo] = addr[UnusedCargo]
+               }
+       }
+
+       // Check that we didn't lose track of any temporary modifications to other.
+       for i := 0; i < NumDimensions; i++ {
+               if addr[i] != other[i] {
+                       panic(i)

                }
        }
                }
        }

-       return best
+
+       // Sanity check: This cell was in state BEING_EVALUATED
+       // the whole time that it was being evaluated.
+       if table[my_index].value != VALUE_BEING_EVALUATED {
+               panic(my_index)
+       }
+
+       // Record our findings
+       table[my_index].value = best_value
+       table[my_index].from = EncodeIndex(dims, best_source)
+
+       // UI: Progress bar
+       cell_filled_count++
+       if cell_filled_count&0xff == 0 {
+               print(fmt.Sprintf("\r%3.1f%%", 100*float64(cell_filled_count)/float64(StateTableSize(dims))))
+       }
+
+       return table[my_index].value
+}
+
+func FindBestState(data planet_data, dims []int, table []State) int32 {
+       addr := make([]int, NumDimensions)
+       addr[Edens] = *end_edens
+       addr[Cloaks] = dims[Cloaks] - 1
+       addr[BuyFighters] = dims[BuyFighters] - 1
+       addr[BuyShields] = dims[BuyShields] - 1
+       addr[Visit] = dims[Visit] - 1
+       addr[Traded] = 1
+       addr[Hold] = 0
+       addr[UnusedCargo] = 0
+       max_index := int32(-1)
+       max_value := int32(0)
+       max_fuel := 1
+       if *fuel == 0 {
+               max_fuel = 0
+       }
+       for addr[Fuel] = 0; addr[Fuel] <= max_fuel; addr[Fuel]++ {
+               for addr[Location] = 0; addr[Location] < dims[Location]; addr[Location]++ {
+                       if len(end()) == 0 || end()[data.i2p[addr[Location]]] {
+                               index := EncodeIndex(dims, addr)
+                               value := CellValue(data, dims, table, addr)
+                               if value > max_value {
+                                       max_value = value
+                                       max_index = index
+                               }
+                       }
+               }
+       }
+       return max_index
+}
+
+func Commas(n int32) (s string) {
+       r := n % 1000
+       n /= 1000
+       for n > 0 {
+               s = fmt.Sprintf(",%03d", r) + s
+               r = n % 1000
+               n /= 1000
+       }
+       s = fmt.Sprint(r) + s
+       return
+}
+
+func DescribePath(data planet_data, dims []int, table []State, start int32) (description []string) {
+       for index := start; table[index].from > FROM_ROOT; index = table[index].from {
+               if table[index].from == FROM_UNINITIALIZED {
+                       panic(index)
+               }
+               var line string
+               addr := DecodeIndex(dims, index)
+               prev := DecodeIndex(dims, table[index].from)
+               if addr[Fuel] != prev[Fuel] {
+                       from := data.i2p[prev[Location]]
+                       to := data.i2p[addr[Location]]
+                       line += fmt.Sprintf("Jump from %v to %v (%v hyper jump units)", from, to, prev[Fuel]-addr[Fuel])
+               }
+               if addr[Edens] == prev[Edens]-1 {
+                       from := data.i2p[prev[Location]]
+                       to := data.i2p[addr[Location]]
+                       line += fmt.Sprintf("Eden warp from %v to %v", from, to)
+               }
+               if addr[Hold] != prev[Hold] {
+                       if addr[Hold] == 0 {
+                               quantity := *hold - (prev[UnusedCargo] + prev[Edens] + prev[Cloaks])
+                               line += fmt.Sprintf("Sell %v %v", quantity, data.i2c[prev[Hold]])
+                       } else if prev[Hold] == 0 {
+                               quantity := *hold - (addr[UnusedCargo] + addr[Edens] + addr[Cloaks])
+                               line += fmt.Sprintf("Buy %v %v", quantity, data.i2c[addr[Hold]])
+                       } else {
+                               panic("Switched cargo?")
+                       }
+
+               }
+               if addr[Cloaks] == 1 && prev[Cloaks] == 0 {
+                       // TODO: Dump cloaks, convert from cargo?
+                       line += "Buy a Cloak"
+               }
+               if addr[Edens] > prev[Edens] {
+                       line += fmt.Sprint("Buy ", addr[Edens]-prev[Edens], " Eden Warp Units")
+               }
+               if addr[BuyShields] == 1 && prev[BuyShields] == 0 {
+                       line += fmt.Sprint("Buy ", *batteries, " Shield Batterys")
+               }
+               if addr[BuyFighters] == 1 && prev[BuyFighters] == 0 {
+                       line += fmt.Sprint("Buy ", *drones, " Fighter Drones")
+               }
+               if addr[Visit] != prev[Visit] {
+                       // TODO: verify that the bit chat changed is addr[Location]
+                       line += fmt.Sprint("Visit ", data.i2p[addr[Location]])
+               }
+               if line == "" && addr[Hold] == prev[Hold] && addr[Traded] != prev[Traded] {
+                       // The Traded dimension is for housekeeping.  It doesn't directly
+                       // correspond to in-game actions, so don't report transitions.
+                       continue
+               }
+               if line == "" {
+                       line = fmt.Sprint(prev, " -> ", addr)
+               }
+               description = append(description, fmt.Sprintf("%13v ", Commas(table[index].value))+line)
+       }
+       return

 }
 
 // (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()
 }
 
 func main() {
        flag.Parse()

+       if *start == "" || *funds == 0 {
+               print("--start and --funds are required.  --help for more\n")
+               return
+       }
+       if *cpuprofile != "" {
+               f, err := os.Create(*cpuprofile)
+               if err != nil {
+                       panic(err)
+               }
+               pprof.StartCPUProfile(f)
+               defer pprof.StopCPUProfile()
+       }

        data := ReadData()
        data := ReadData()

-       data.pi = IndexPlanets(&data.Planets)
-       data.ci = IndexCommodities(&data.Commodities)
+       if *drone_price > 0 {
+               temp := data.Commodities["Fighter Drones"]
+               temp.BasePrice = *drone_price
+               data.Commodities["Fighter Drones"] = temp
+       }
+       if *battery_price > 0 {
+               temp := data.Commodities["Shield Batterys"]
+               temp.BasePrice = *battery_price
+               data.Commodities["Shield Batterys"] = temp
+       }
+       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[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]]
-                       }
-                       fmt.Printf("%s to %s: %s\n", from, to, best_trade)
+       table := CreateStateTable(data, dims)
+       best := FindBestState(data, dims, table)
+       print("\n")
+       if best == -1 {
+               print("Cannot acheive success criteria\n")
+       } else {
+               description := DescribePath(data, dims, table, best)
+               for i := len(description) - 1; i >= 0; i-- {
+                       fmt.Println(description[i])

                }
        }
 }
                }
        }
 }