Databases
StackOverflow2013
Postsdbo
POHow to improve performance of this code?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow to improve performance of this code?
    primarykey
    data
    text
    <p>Thanks to some help from people here, I was able to get my code for Tasmanian camels puzzle working. However, it is horribly slow (I think. I'm not sure because this is my first program in Python). The example run in the bottom of the code takes a long time to be solved in my machine:</p> <pre><code>dumrat@dumrat:~/programming/python$ time python camels.py [['F', 'F', 'F', 'G', 'B', 'B', 'B'], ['F', 'F', 'G', 'F', 'B', 'B', 'B'], ['F', 'F', 'B', 'F', 'G', 'B', 'B'], ['F', 'F', 'B', 'F', 'B', 'G', 'B'], ['F', 'F', 'B', 'G', 'B', 'F', 'B'], ['F', 'G', 'B', 'F', 'B', 'F', 'B'], ['G', 'F', 'B', 'F', 'B', 'F', 'B'], ['B', 'F', 'G', 'F', 'B', 'F', 'B'], ['B', 'F', 'B', 'F', 'G', 'F', 'B'], ['B', 'F', 'B', 'F', 'B', 'F', 'G'], ['B', 'F', 'B', 'F', 'B', 'G', 'F'], ['B', 'F', 'B', 'G', 'B', 'F', 'F'], ['B', 'G', 'B', 'F', 'B', 'F', 'F'], ['B', 'B', 'G', 'F', 'B', 'F', 'F'], ['B', 'B', 'B', 'F', 'G', 'F', 'F']] real 0m20.883s user 0m20.549s sys 0m0.020s </code></pre> <p>Here's the code:</p> <pre><code>import Queue fCamel = 'F' bCamel = 'B' gap = 'G' def solution(formation): return len([i for i in formation[formation.index(fCamel) + 1:] if i == bCamel]) == 0 def heuristic(formation): fCamels, score = 0, 0 for i in formation: if i == fCamel: fCamels += 1; elif i == bCamel: score += fCamels; else: pass return score def getneighbors (formation): igap = formation.index(gap) res = [] # AB_CD --&gt; A_BCD | ABC_D | B_ACD | ABD_C def genn(i,j): temp = list(formation) temp[i], temp[j] = temp[j], temp[i] res.append(temp) if(igap &gt; 0): genn(igap, igap-1) if(igap &gt; 1): genn(igap, igap-2) if igap &lt; len(formation) - 1: genn(igap, igap+1) if igap &lt; len(formation) - 2: genn(igap, igap+2) return res class node: def __init__(self, a, g, p): self.arrangement = a self.g = g self.parent = p def astar (formation, heuristicf, solutionf, genneighbors): openlist = Queue.PriorityQueue() openlist.put((heuristicf(formation), node(formation, 0, None))) closedlist = [] while 1: try: f, current = openlist.get() except IndexError: current = None if current is None: print "No solution found" return None; if solutionf(current.arrangement): path = [] cp = current while cp != None: path.append(cp.arrangement) cp = cp.parent path.reverse() return path #arr = current.arrangement closedlist.append(current) neighbors = genneighbors(current.arrangement) for neighbor in neighbors: if neighbor in closedlist: pass else: openlist.put((current.g + heuristicf(neighbor), node(neighbor, current.g + 1, current))) #sorted(openlist, cmp = lambda x, y : x.f &gt; y.f) def solve(formation): return astar(formation, heuristic, solution, getneighbors) print solve([fCamel, fCamel, fCamel, gap, bCamel, bCamel, bCamel]) #print solve([fCamel, fCamel, fCamel, fCamel, gap, bCamel, bCamel, bCamel, bCamel]) </code></pre> <p>That is just for 3 camels each. I wanted to do this for 4 at least. That test case is still running (It's been about 5 minutes now :(). I'll update this if and when it finishes.</p> <p>What should I do to improve this code? (Mostly performance-wise, but any other suggestions are welcome also).</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USPeter Mortensen
    1. USnakiya
    plurals
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow to improve performance of this code?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POHow to improve performance of this code?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POHow to improve performance of this code?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COWhat is the `Queue.PriorityQueue()` used for?
      singulars
      1. POHow to improve performance of this code?
      1. USkennytm
    2. CO@nakiya: Use http://docs.python.org/library/heapq.html#module-heapq for a priority queue if you don't intend to create a multi-threaded program. (This isn't the bottleneck though.)
      singulars
      1. POHow to improve performance of this code?
      1. USkennytm
    3. CO@KennyTM: I tried it. But I think it must be in some collection. I just went through with the priority queue. NameError: name 'heappush' is not defined
      singulars
      1. POHow to improve performance of this code?
      1. USnakiya
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload