# which library has map reduce and how to use it for this case

Ho Yeung Lee davidbenny2000 at gmail.com
Thu Jun 9 21:07:04 EDT 2016

```input are these six operators, output is finding full column of 27 elements add together is 54

i got memory error when searching this,

i have difficulty in understanding map reduce and transforming my program into map reduce problem

M1 = {}
M2 = {}
M3 = {}
M4 = {}
M5 = {}
V6 = {}
M1['00']=0
M1['01']=2
M1['02']=1
M1['10']=1
M1['11']=1
M1['12']=1
M1['20']=1
M1['21']=1
M1['22']=2
M2['00']=0
M2['01']=1
M2['02']=1
M2['10']=1
M2['11']=1
M2['12']=1
M2['20']=1
M2['21']=1
M2['22']=1
M3['00']=2
M3['01']=2
M3['02']=2
M3['10']=0
M3['11']=2
M3['12']=1
M3['20']=0
M3['21']=1
M3['22']=2
M4['00']=1
M4['01']=2
M4['02']=1
M4['10']=2
M4['11']=2
M4['12']=2
M4['20']=0
M4['21']=1
M4['22']=2
M5['00']=0
M5['01']=1
M5['02']=1
M5['10']=0
M5['11']=2
M5['12']=1
M5['20']=0
M5['21']=1
M5['22']=1
V6['00']=1
V6['01']=1
V6['02']=2
V6['10']=1
V6['11']=2
V6['12']=1
V6['20']=1
V6['21']=2
V6['22']=2
MM = {}
MM = M1
MM = M2
MM = M3
MM = M4
MM = M5
MM = 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 = []
#print(len(list(itertools.combinations(initlist, 2))))
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:
#print(len(list(itertools.combinations(initlist, 2))))
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)

Michael Selik於 2016年6月10日星期五 UTC+8上午6時45分14秒寫道：
> I like using Yelp's mrjob module (https://github.com/Yelp/mrjob) to run
> Python on Hadoop.
>
> On Thu, Jun 9, 2016 at 2:56 AM Ho Yeung Lee <davidbenny2000 at gmail.com>
> wrote:
>
> > [... a bunch of code ...]
>
>
> If you want to describe a map-reduce problem, start with the data. What
> does a record of your input data look like?
>
> Then think about your mapper. What key-value pairs will you extract from
> each line of data?
>
> Then think about your reducer. For a single key and its associated values,
> what will you calculate?

```

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