fix mask selection

faststack.nim

@@ -29,7 +29,7 @@ const
 template offset(s: ColorStack, idx: Natural): uint8 =
   # Compute the bit offset for a given index. 
   # Dependent on the stack's length.
-  (s.len - 1 - cast[uint8](idx)) * 3
+  (s.len - 1 - idx.uint8) * 3
   # items are stored from left to right but right-aligned, so we
   # need to shift right to access anything other than the last
 
@@ -37,7 +37,7 @@ template offset(s: ColorStack, idx: Natural): uint8 =
 template offset(s: ColorStack, idx: BackwardsIndex): uint8 =
   # for backwards index, we are still shifting right but
   # the lower the index the less we have to shift
-  (cast[uint8](idx) - 1) * 3
+  (idx.uint8 - 1) * 3
 
 
 proc add*(s: var ColorStack, c: Color) =
@@ -57,21 +57,21 @@ proc low*(s: ColorStack): uint8 = 0 # just... always 0, I guess
 
 proc `[]`*(s: ColorStack, i: uint8 | BackwardsIndex): Color =
   # shift, then mask everything but the three rightmost bits
-  result = cast[Color](
+  result = Color(
     (s.data shr s.offset(i)) and masks[1]
   )
 
 
 proc `[]=`*(s: var ColorStack, i: uint8 | BackwardsIndex, c: Color) =
   let offset = s.offset(i)
-  s.data = (s.data and bitnot(masks[1] shl offset)) or (cast[uint16](c) shl offset)
+  s.data = (s.data and bitnot(masks[1] shl offset)) or (c.uint16 shl offset)
 
 
 iterator items*(s: ColorStack): Color =
   # s.len is unsigned so it will wrap around if we do s.len - 1 in that case
   if s.len != 0:
     for i in countdown(s.len - 1, 0'u8):
-      yield cast[Color]((s.data shr (i * 3)) and masks[1])
+      yield Color((s.data shr (i * 3)) and masks[1])
 
 
 iterator pairs*(s: ColorStack): (uint8, Color) =
@@ -81,13 +81,16 @@ iterator pairs*(s: ColorStack): (uint8, Color) =
     inc count
 
 
-proc find*(s: ColorStack, needle: Color): uint8 =
+proc find*(s: ColorStack, needle: Color): int8 =
   for i in 0'u8 .. s.high:
     if s[i] == needle:
-      return i
+      return i.int8
+  return -1
 
 
 proc moveSubstack*(src, dst: var ColorStack, startIdx: uint8) =
+  if startIdx >= src.len:
+    raise newException(IndexDefect, "index " & $startIdx & " is out of bounds.")
   # Moves a sub-stack from the top of src to the top of dst
   # shift the dst stack by the length of the substack to make room
   let nToMove = src.len - startIdx
@@ -95,9 +98,7 @@ proc moveSubstack*(src, dst: var ColorStack, startIdx: uint8) =
   dst.data = dst.data shl shift
   # then we mask the source data to present only the items 
   # being moved, and OR that with the shifted dst data
-  if src.len > 5:
+  dst.data = dst.data or (src.data and masks[nToMove])
-    echo src.len
-  dst.data = dst.data or (src.data and masks[src.len])
   dst.len += nToMove
   # then we shift the source to get rid of the moved items
   src.data = src.data shr shift
@@ -105,13 +106,16 @@ proc moveSubstack*(src, dst: var ColorStack, startIdx: uint8) =
 
 
 proc moveSubstackPre*(src, dst: var ColorStack, startIdx: uint8) =
+  if startIdx >= src.len:
+    raise newException(IndexDefect, "index " & $startIdx & " is out of bounds.")
   # Moves a sub-stack from the top of src to the bottom of dst
   let nToMove = src.len - startIdx
-  # shift src stack to position substack above its destination,
+  # shift src to position the substack above its destination,
   # get rid of everything to the left of the substack,
   # and OR that with the existing dst data
-  dst.data = dst.data or ( (src.data shl (dst.len * 3)) and masks[src.len])
+  let newLen = dst.len + nToMove
-  dst.len += nToMove
+  dst.data = dst.data or ( (src.data shl (dst.len * 3)) and masks[newLen] )
+  dst.len = newLen
   # get rid of the substack we just moved
   src.data = src.data shr (nToMove * 3)
   src.len -= nToMove
@@ -142,7 +146,7 @@ proc swap*(s: var ColorStack, i1, i2: uint8) =
 proc shuffle*(r: var Rand, s: var ColorStack) =
   # Fisher-Yates shuffle
   for i in countdown(s.high, 1'u8):
-    let j = cast[uint8](r.rand(i))
+    let j = r.rand(i).uint8
     if j != i:
       s.swap(i, j)
 
@@ -170,6 +174,19 @@ proc `$`*(s: ColorStack): string =
   result.add("]")
 
 
+proc check(s: ColorStack) =
+  # ensure length is accurate
+  var d = s.data
+  for i in 0'u8 .. 4'u8:
+    if (d and masks[1]) > 4:
+      raise newException(RangeDefect, "Value out of range.")
+    if d > 0 and i >= s.len:
+      raise newException(RangeDefect, "Invalid length.")
+    else:
+      d = d shr 3
+
+
+when isMainModule:
   var one: ColorStack
   one.add(cRed)
   one.add(cGreen)
@@ -180,7 +197,8 @@ one.add(cPurple)
   var two: ColorStack
 
   one.moveSubstack(two, 2)
-two.moveSubstackPre(one, 1)
+
 
   echo one, " ", one.len
   echo two, " ", two.len
+  echo two.find(cRed)

game.nim

@@ -141,7 +141,7 @@ proc advance*(b: var Board, die: Die) =
     endPos += int(t)
     if t == tBackward: prepend = true
 
-  let stackStart = b[startPos].camels.find(color)
+  let stackStart = b[startPos].camels.find(color).uint8
   if prepend:
     b[startPos].camels.moveSubstackPre(b[endPos].camels, stackStart)
     let stackLen = b[startPos].camels.len - stackStart

simulation.nim

@@ -1,5 +1,5 @@
 import cpuinfo, math, options, random, tables
-import combinators, game, fixedseq
+import combinators, game, faststack, fixedseq
 
 
 type
@@ -59,6 +59,39 @@ proc getLegScores*(b: Board): ScoreSet =
 # Full-game simulations
 # =====================
 
+# get rid of this later
+import strutils
+proc showSpaces*(b: Board; start, stop: Natural): string =
+  let numSpaces = stop - start + 1
+  let width = 4 * numSpaces - 1
+  var lines: array[7, string]
+  # start by building up an empty board
+  for i in 0 .. 6: # gotta initialize the strings
+    lines[i] = newString(width)
+    for c in lines[i].mitems:
+      c = ' '
+  # fill in the dividers
+  lines[5] = repeat("=== ", numSpaces - 1)
+  lines[5].add("===")
+
+  # now populate the board
+  for sp in 0 ..< numSpaces:
+    # fill in the square numbers
+    let squareNum = sp + start
+    let cellMid = 4 * sp + 1
+    for i, chr in $squareNum:
+      lines[6][cellMid + i] = chr
+
+    # fill in the camel stacks
+    for i, color in b.squares[squareNum].camels:
+      let lineNum = 4 - i # lines go to 6, but bottom 2 are reserved
+      let repr = '|' & color.abbrev & '|'
+      for j, chr in repr:
+        lines[lineNum][cellMid - 1 + j] = chr
+
+  result = lines.join("\n")
+# get rid of this later
+
 proc randomGame*(b: Board, r: var Rand): Color =
   var projection = b
   while true:

test.nim

@@ -43,13 +43,13 @@ proc newRandomGame(r: var Rand): Board =
   result.setState(dice, [])
 
 
-proc games(nTests, nSamples: SomeInteger): TestResults =
+proc games(nTests, nSamples: SomeInteger, parallel = true): TestResults =
   var r = getRand()
   var scores: ScoreSet
   for i in 1 .. nTests:
     let b = newRandomGame(r)
     let dur = executionTime:
-      let s = b.randomGames(nSamples)
+        let s = b.randomGames(nSamples, parallel = parallel)
     result.ops += s.sum()
     result.time += dur
 
@@ -94,17 +94,4 @@ proc testSpread(nTests, nSamples: Natural) =
 
 
 when isMainModule:
-  games(10, 1_000_000).summarize()
+  games(10, 10_000_000).summarize()
-  # let start_states = 2_000
-  # let executionTime = testLegs(start_states)
-  # echo "Execution time: ", executionTime
-  # echo "Leg simulations per second: ", float(start_states * 29_160) / executionTime
-
-  # for i in 1 .. 1:
-  #   let num_games = 100_000_005
-  #   let executionTime = testGames(num_games)
-  #   echo "Execution time: ", executionTime
-  #   echo "Full-game simulations per second: ", float(num_games) / executionTime
-  #   echo ""
-
-  # testSpread(100, 1_000_000)