Re: Making a large matrix
- To: mathgroup at smc.vnet.net
- Subject: [mg14856] Re: Making a large matrix
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Fri, 20 Nov 1998 02:17:02 -0500
- References: <72tt72$isd@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Ersek, Ted R wrote in message <72tt72$isd at smc.vnet.net>...
>Consider the timing experiments below for making a large matrix of
>random real numbers.
>
>In[1]:=
>Table[Table[Random[],{1000}],{500}];//Timing Out[1]=
>{17.47 Second,Null}
>
>In[2]:=
>Table[Range[Random[],1000],{500}];//Timing Out[2]=
>{9.56 Second,Null}
>
>In[3]:=
>MakeMatrix=Compile[{m,n},Table[Range[Random[],n],{m}]];
> (* Make an (m,n) matrix. *)
>
>In[4]:=
>MakeMatrix[500,1000];//Timing
>Out[4]=
>{5.82 Second,Null}
>
>The last method is the fastest method I can come up with. Can any of
>you find a faster way to make a large matrix with Mathematica? (short
>of using MathLink to run an executable program).
>
>Cheers,
>Ted Ersek
>
>
Ted,
Range[Random[], 1000] does not give random entries:
Range[Random[], 6]
{0.77037,1.77037,2.77037,3.77037,4.77037,5.77037}
Allan
---------------------
Allan Hayes
Mathematica Training and Consulting
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