[URGENT]ERLANG C - POISSON DISTRIBUTION - SUMMATION

[erichshiino]

Hello everyone!

I need some help to implement the Erlang C formula on Qlikview. This expresses the waiting probability in a queuing system.

You can find the formula (and explanation) on this site:

http://www.mitan.co.uk/erlang/elgcmath.htm

Basically, I can be done on Excel with the Poisson Distribution but I could not find it on Qlikiview.

I could write it directly using the expression on the site but I could not find the summation formula on Qlikview.

As far as I know we are not able to create custom formulas.

Has anyone faced a problem like this before?

Thanks in advance.

Erich

[#2 · Accepted solution]

Hi Erich,

I dont think there is a readymade formula for this in Qlikview but you can achieve it by creating variables and applying formula on top of these. Please refer to attached qvw file where I have implemented Erlang C formula using following variables: vOcc, vNum, vDen. Also refer to the script where I have evaulated the variable vDen using for loop.

Let me know if this is of help or you need some more information.

Thanks

Amit

[#3]

Hi Erich,

I know im very late for this post. Hope it may help others.

With reference to The Erlang-C Formula - An Introduction

Create the below mentioned variables

vArrivalRate ->   num(NoOfCalls/(Period)) 

vTrafficIntensity -> num(Ts*vArrivalRate )

vAgentOccupancy -> num([vTraffic Intensity]/vNoOfAgents)

vNum -> pow([vTraffic Intensity],vNoOfAgents)/fact(vNoOfAgents)

Using the above variables you can calculate ErlangC

vErlangC ->  vNum/(vNum+(1-vAgentOccupancy)*sum(pow([vTraffic Intensity],ValueLoop(0,vNoOfAgents-1,1))/fact(valueloop(0,vNoOfAgents-1,1))))

[nate_eyster]

Has anyone got this to work within a table, looping over the No. of Agents by using Valueloop?