i write a program, it is like forever loop but i only restrict it to run 2 level recursively,
why it is slow, where is the problem? M1 = {} M2 = {} M3 = {} M4 = {} M5 = {} V6 = {} M1['00']=0 M1['01']=1 M1['02']=1 M1['10']=2 M1['11']=2 M1['12']=1 M1['20']=1 M1['21']=2 M1['22']=1 M2['00']=0 M2['01']=1 M2['02']=2 M2['10']=1 M2['11']=2 M2['12']=1 M2['20']=1 M2['21']=1 M2['22']=1 M3['00']=0 M3['01']=2 M3['02']=2 M3['10']=1 M3['11']=2 M3['12']=1 M3['20']=0 M3['21']=1 M3['22']=0 M4['00']=2 M4['01']=2 M4['02']=0 M4['10']=2 M4['11']=1 M4['12']=2 M4['20']=0 M4['21']=1 M4['22']=2 M5['00']=0 M5['01']=1 M5['02']=2 M5['10']=1 M5['11']=1 M5['12']=1 M5['20']=1 M5['21']=1 M5['22']=2 V6['00']=1 V6['01']=2 V6['02']=1 V6['10']=2 V6['11']=1 V6['12']=1 V6['20']=2 V6['21']=2 V6['22']=0 MM = {} MM[0] = M1 MM[1] = M2 MM[2] = M3 MM[3] = M4 MM[4] = M5 MM[5] = V6 m = 3 b = [str(i)+str(j)+str(k) for i in range(m) for j in range(m) for k in range(m)] import itertools deep = 3 final = [] mylist = [MM[i] for i in range(0,7-1)] b = [str(i)+str(j)+str(k) for i in range(m) for j in range(m) for k in range(m)] def DFS(b, deep, maxx, sourceoperators, path): initlist = [] if deep > 0: print("deep=", deep) for aa,bb in itertools.combinations(sourceoperators, 2): print(aa,bb) if deep == maxx: finalresult = [] op1xy = [aa[b[i][0:1]+b[i][1:2]] for i in range(len(b))] op1yz = [aa[b[i][1:2]+b[i][2:3]] for i in range(len(b))] op1xz = [aa[b[i][0:1]+b[i][2:3]] for i in range(len(b))] op2xy = [bb[b[i][0:1]+b[i][1:2]] for i in range(len(b))] op2yz = [bb[b[i][1:2]+b[i][2:3]] for i in range(len(b))] op2xz = [bb[b[i][0:1]+b[i][2:3]] for i in range(len(b))] if sum(op1xy) == 54: path.append([(deep, aa, "xy")]) if sum(op1yz) == 54: path.append([(deep, aa, "yz")]) if sum(op1xz) == 54: path.append([(deep, aa, "xz")]) if sum(op2xy) == 54: path.append([(deep, bb, "xy")]) if sum(op2yz) == 54: path.append([(deep, bb, "yz")]) if sum(op2xz) == 54: path.append([(deep, bb, "xz")]) initlist.append(op1xy) initlist.append(op1yz) initlist.append(op1xz) initlist.append(op2xy) initlist.append(op2yz) initlist.append(op2xz) else: level = [] for j in range(len(b)): op1xy = [aa[b[j][i]] for i in range(len(b[j]))] op2xy = [bb[b[j][i]] for i in range(len(b[j]))] if sum(op1xy) == 54: path.append([(deep, aa, "xy")]) if sum(op2xy) == 54: path.append([(deep, bb, "xy")]) level.append(op1xy) level.append(op2xy) initlist.append(op1xy) initlist.append(op2xy) if deep == maxx: b = [] for aaa,bbb in itertools.combinations(initlist, 2): b.append([str(i)+str(j) for i,j in zip(aaa, bbb)]) path = DFS(b, deep-1, maxx, sourceoperators, path) else: for aaa,bbb in itertools.combinations(initlist, 2): b.append([str(i)+str(j) for i,j in zip(aaa, bbb)]) path = DFS(b, deep-1, maxx, sourceoperators, path) return path path = [] mresult = DFS(b, 2, 2, mylist, path) -- https://mail.python.org/mailman/listinfo/python-list