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Topic: How to generate 2D Frequency Matrix
Replies: 8   Last Post: Dec 3, 2012 8:54 AM

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S Ehtesham Al Hanif

Posts: 9
Registered: 12/1/12
Re: How to generate 2D Frequency Matrix
Posted: Dec 3, 2012 3:00 AM
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"Roger Stafford" wrote in message <k9hjca$bro$1@newscl01ah.mathworks.com>...
> "S Ehtesham Al Hanif" <ehtesham.buet@gmail.com> wrote in message <k9hhls$6gh$1@newscl01ah.mathworks.com>...
> > Actually, I have data?s like below:
> > A B
> > 4.8 1.34
> > 9.5 1.30
> > 13.8 1.21
> > 18.5 1.30
> > 23.0 1.25
> > 27.2 1.16
> > 27.9 0.18
> > 29.1 0.36
> > 33.3 1.16
> > 34.9 0.45
> > 36.1 0.31
> > 36.2 0.04
> > 35.6 -0.18
> > 34.6 -0.27
> > 33.6 -0.27
> > 32.8 -0.22
> > 31.9 -0.27
> > 27.4 -1.25
> > 24.0 -0.94
> > 24.0 0.00
> >
> > Now I want to generate a matrix with frequency distribution like below
> > A\B -1 -2 0 1 2
> > 0-5 x x x x x
> > 5-10 x x x x x
> > 10-15 x x x x x
> > 15-20 x x x x x
> >
> > These x (frequency) I have to find out and these, x will be a (mxn) matrix based on those condition. Each x will have to fulfill A(0-5,5-10 etc) & B(-1,-2,0, etc) matrix at a same time then when full column matrix complete then the resultant X(mxn) matrix with overall frequency.

> - - - - - - - - - -
> I don't understand your example. For instance, which of the 20 x's does the pair (36.2 , 0.04) contribute to? Your A column values go beyond the intervals you describe and the B conditions aren't intervals.
>
> Roger Stafford


Hi Roger

Actually in my case, I have three column but i can avoid first one which has time value. In details:
Column T has value of time as second t=1:1:1400;
Column A has value of velocity/speed and it has 1400 speed values from 0(zero) to 100(hundred). In this case some velocity values repeats after uncertain interval.
Column B has value of acceleration and it has 1400 acceleration/deccelaration values from --4(minus four) to +4(four). In this case some acceleration values has repetition.

Now i want to generate a mxn matrix where every position will be a frequency which can full fill one condition from A and same time one corresponding B condition.

I subdivided velocity column into several group, such as: 0 to 5, 5 to 10, 10 to 15, 15 to 20 .........90 to 95 and 95-100.

Similarly i subdivided acceleration column into several group such as: -4 to -3, -3 to -2 ...... 2 to 3 and 3 to 4.

Then, i will count frequency such a way that it will full fill both columns same row with those condition.

As an example: if i look at the previous posts Column A. And Column B, then i have to find out how many times/frequency the below conditioned fullfilled?

If velocity range : 30 to 35 m/s and acceleration at the same time/row in -0.5 to -0.25 range ? According to example it has frequent/count 3! If velocity range same but acceleration condition changed to -0.25 to 0 then it has frequency 1.

I think this time my illustration is better as if it is possible to show you by showing picture or figure by attaching here it will be easy to explain what i am planning for!

Ehtesham



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