Date: Nov 15, 2013 6:53 AM
Author: emammendes@gmail.com
Subject: Re: Help with Manipulate

Hello

Many many thanks.

I went through the code you sent me to see if I can understand it. There is one piece that I don't understand. Here is it


> (z = generate[\[Lambda], n]) &

Why do I need &?

Thanks again.

Cheers

Ed


On Nov 14, 2013, at 8:39 AM, Waclaw Kusnierczyk <waku@idi.ntnu.no> wrote:

> Will this solve your problem:
>
> With[{generate =
> RandomVariate[Quiet@ExponentialDistribution[#1], #2 - 1] &},
> Module[{z},
> Manipulate[
> z = generate[\[Lambda], n];
> n/Total[z],
> Button["generate", (z = generate[\[Lambda], n]) &],
> {{\[Lambda], 2}, 1, 100, 1},
> {{n, 10000}, 2, 1000000, 1000}]]]
>
> Best,
> vQ
>
>
> On 11/14/2013 08:11 AM, Eduardo M. A. M. Mendes wrote:

>>
>> I need to create a simple demonstration based upon an exercise on poisson counting processes. Here is the code
>>
>> Manipulate[n/Total[z],Style["Poisson Arrival Times",18,Bold],"",Delimiter,{{z,Flatten[{0,RandomVariate[Quiet@ExponentialDistribution[\[Lambda]],n-1]}]},Button["random",z=Flatten[{0,RandomVariate[Quiet@ExponentialDistribution[\[Lambda]],n-1]}]]&,Appearance->"Labeled"},"",Delimiter,{{\[Lambda],2,"\[Lambda]"},1,100,1,Appearance->"Labeled"},"",Delimiter,{{n,10000,"n"},1,1000000,1000,Appearance->"Labeled"},SaveDefinitions->True]
>>
>> The idea is to generate a sequence of random numbers, then take the sum of it and keep the last value. Every time I hit "random"a new sequence is created.
>>
>> The above code returns the following error msg
>>
>> RandomVariate::array : "\"The array dimensions -1 + n given in position 2 \
>> of RandomVariate[ExponentialDistribution[=CE=BB], -1 + n] should be a list of \
>> non-negative machine-sized integers giving the dimensions for the result. \""
>>
>> and some weird output. After hitting "random", the output is what I expect but the whole Manipulate output is still red indicating that there are problems.
>>
>> Could you be so kind to point out what I did wrong and how to fix it? I feel that I did not quite get how Manipulate works.