Why is there difference between cmd line and .py file?
Robert
rxjwg98 at gmail.com
Tue Jan 5 15:41:41 EST 2016
On Tuesday, January 5, 2016 at 3:26:15 PM UTC-5, Robert wrote:
> Hi,
>
> I run below code, which is downloaded from link:
>
> http://stackoverflow.com/questions/15513792/expectation-maximization-coin-toss-examples?rq=1
>
>
>
> ////////////
> # represent the experiments
> head_counts = np.array([5,9,8,4,7])
> tail_counts = 10-head_counts
> experiments = zip(head_counts,tail_counts)
>
> # initialise the pA(heads) and pB(heads)
> pA_heads = np.zeros(100); pA_heads[0] = 0.60
> pB_heads = np.zeros(100); pB_heads[0] = 0.50
>
> # E-M begins!
> delta = 0.001
> j = 0 # iteration counter
> improvement = float('inf')
> while (improvement>delta):
> expectation_A = np.zeros((5,2), dtype=float)
> expectation_B = np.zeros((5,2), dtype=float)
> for i in range(0,len(experiments)):
> e = experiments[i] # i'th experiment
> ll_A = get_mn_log_likelihood(e,np.array([pA_heads[j],1-pA_heads[j]])) # loglikelihood of e given coin A
> ll_B = get_mn_log_likelihood(e,np.array([pB_heads[j],1-pB_heads[j]])) # loglikelihood of e given coin B
>
> weightA = math.exp(ll_A) / ( math.exp(ll_A) + math.exp(ll_B) ) # corresponding weight of A proportional to likelihood of A
> weightB = math.exp(ll_B) / ( math.exp(ll_A) + math.exp(ll_B) ) # corresponding weight of B proportional to likelihood of B
>
> expectation_A[i] = np.dot(weightA, e)
> expectation_B[i] = np.dot(weightB, e)
>
> print "sum(expectation_A)[0]", sum(expectation_A)[0]
> pA_heads[j+1] = sum(expectation_A)[0] / sum(sum(expectation_A));
> pB_heads[j+1] = sum(expectation_B)[0] / sum(sum(expectation_B));
> //////////
> The print message is:
> sum(expectation_A)[0] 21.2974818963
> sum(expectation_A)[0] 19.2093824201
> sum(expectation_A)[0] 19.4102767983
> sum(expectation_A)[0] 19.7538328728
> sum(expectation_A)[0] 19.9753285438
> sum(expectation_A)[0] 20.0879016403
> sum(expectation_A)[0] 20.139820175
> sum(expectation_A)[0] 20.1628374165
>
>
>
> When I check below in detail in interactive mode (Canopy Python shell),
>
> sum(expectation_A)[0]
>
> it has error:
> /////////////
> sum(expectation_A)[0]
> ---------------------------------------------------------------------------
> IndexError Traceback (most recent call last)
> <ipython-input-145-d6f33dff0343> in <module>()
> ----> 1 sum(expectation_A)[0]
>
> IndexError: invalid index to scalar variable.
> //////////////
>
> I can see expectation_A content with:
>
> In[146]:expectation_A
> Out[146]:
> array([[ 0.52278641, 0.52278641],
> [ 8.55858656, 0.95095406],
> [ 6.75024946, 1.68756237],
> [ 0.1260128 , 0.1890192 ],
> [ 4.20520218, 1.80222951]])
>
> It looks like
> sum(expectation_A)[0]
>
> can run in .py file, while it cannot be run in python shell.
> Is it true?
>
> Thanks,
I just wonder that the cmd line function sum may be different from the
.py file used. One is numpy package, the other is a general one. Then,
how can I further make it clear for this guess?
Thanks,
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