Re: Curious Timing Results
- To: mathgroup at smc.vnet.net
- Subject: [mg38663] Re: Curious Timing Results
- From: Bill Rowe <listuser at earthlink.net>
- Date: Sat, 4 Jan 2003 07:25:43 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
On 1/3/03 at 12:15 AM, grant at math.byu.edu (Chris Grant) wrote:
>I find the Timing results below a little curious. Is there a simple
>explanation why I shouldn't?
>In[1]:= x = Table[2.,{i,100000}];
>In[2]:= y = Table[If[i<1000000,2.,i],{i,100000}];
>In[3]:= SameQ[x,y]
>Out[3]= True
Huh??? The last element of y should be 1000000 while the last element of x should be 2.
>In[4]:= Timing[Inner[Divide,x,x]]
>Out[4]= {0.44 Second,100000.}
>In[5]:= Timing[Inner[Divide,y,y]]
>Out[5]= {0.321 Second,100000.}
Possibly the difference is because one is stored as a packed array and the other isn't.
try Developer`PackedArrayQ[x] and Developer`PackedArrayQ[y]