* 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.
+ * grouped together in large blocks. This keeps the unused cells from
+ * polluting cache lines, and if the spans of unused cells 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 Fuel dimension to 3. Explicit iteration
+ * only ever needs to look backwards 2 units, so the logical values
+ * can rotate through the same 3 physical addresses. This would be
+ * good for an 82% savings. Note that explicit iteration went away
+ * in 0372f045.
* * 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.)
return product
}
+type Value int32
+type PhysicalIndex int32
+
type State struct {
- value, from int32
+ value Value
+ from PhysicalIndex
}
const (
VALUE_RUBISH
)
-func EncodeIndex(dims, addr []int) int32 {
+func EncodeIndex(dims, addr []int) PhysicalIndex {
index := addr[0]
if addr[0] > dims[0] {
panic(0)
}
index = index*dims[i] + addr[i]
}
- return int32(index)
+ return PhysicalIndex(index)
}
-func DecodeIndex(dims []int, index int32) []int {
+func DecodeIndex(dims []int, index PhysicalIndex) []int {
+ scratch := int(index)
addr := make([]int, NumDimensions)
for i := NumDimensions - 1; i > 0; i-- {
- addr[i] = int(index) % dims[i]
- index /= int32(dims[i])
+ addr[i] = scratch % dims[i]
+ scratch /= dims[i]
}
- addr[0] = int(index)
+ addr[0] = scratch
return addr
}
addr[Hold] = data.c2i[*start_hold]
}
start_index := EncodeIndex(dims, addr)
- table[start_index].value = int32(*funds)
+ table[start_index].value = Value(*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) {
+func Consider(data planet_data, dims []int, table []State, there []int, value_difference int, best_value *Value, best_source []int) {
there_value := CellValue(data, dims, table, there)
- if value_difference < 0 && int32(-value_difference) > there_value {
+ if value_difference < 0 && Value(-value_difference) > there_value {
/* Can't afford this transition */
return
}
- possible_value := there_value + int32(value_difference)
+ possible_value := there_value + Value(value_difference)
if possible_value > *best_value {
*best_value = possible_value
copy(best_source, there)
var cell_filled_count int
-func CellValue(data planet_data, dims []int, table []State, addr []int) int32 {
+func CellValue(data planet_data, dims []int, table []State, addr []int) Value {
my_index := EncodeIndex(dims, addr)
if table[my_index].value == VALUE_BEING_EVALUATED {
panic("Circular dependency")
}
table[my_index].value = VALUE_BEING_EVALUATED
- best_value := int32(VALUE_RUBISH)
+ best_value := Value(VALUE_RUBISH)
best_source := make([]int, NumDimensions)
other := make([]int, NumDimensions)
copy(other, addr)
return addr
}
-func FindBestState(data planet_data, dims []int, table []State, addr []int) int32 {
- max_index := int32(-1)
+func FindBestState(data planet_data, dims []int, table []State, addr []int) PhysicalIndex {
+ max_index := PhysicalIndex(-1)
max_value := 0.0
max_fuel := 1
if *fuel == 0 {
return max_index
}
-func Commas(n int32) (s string) {
+func Commas(n Value) (s string) {
if n < 0 {
panic(n)
}
return
}
-func FighterAndShieldCost(data planet_data, dims []int, table []State, best int32) {
+func FighterAndShieldCost(data planet_data, dims []int, table []State, best PhysicalIndex) {
if *drones == 0 && *batteries == 0 {
return
}
}
}
-func EndEdensCost(data planet_data, dims []int, table []State, best int32) {
+func EndEdensCost(data planet_data, dims []int, table []State, best PhysicalIndex) {
if *end_edens == 0 {
return
}
extra_funds := table[alt_best].value - table[best].value
fmt.Println("\rUse", extra_edens, "extra edens, make an extra",
Commas(extra_funds), "(",
- Commas(extra_funds/int32(extra_edens)), "per eden)")
+ Commas(extra_funds/Value(extra_edens)), "per eden)")
}
}
-func VisitCost(data planet_data, dims []int, table []State, best int32) {
+func VisitCost(data planet_data, dims []int, table []State, best PhysicalIndex) {
if dims[Visit] == 1 {
return
}
}
}
-func EndLocationCost(data planet_data, dims []int, table []State, best int32) {
+func EndLocationCost(data planet_data, dims []int, table []State, best PhysicalIndex) {
if len(end()) == 0 {
return
}
*end_string = save_end_string
}
-func DescribePath(data planet_data, dims []int, table []State, start int32) (description []string) {
+func DescribePath(data planet_data, dims []int, table []State, start PhysicalIndex) (description []string) {
for index := start; table[index].from > FROM_ROOT; index = table[index].from {
if table[index].from == FROM_UNINITIALIZED {
panic(index)
projects / planeteer / blobdiff