10 Integers, Highest Value, Siemens

I have a Fifo buffer, values are shifting every 0.2 seconds.

Fifo buffer is 10 integers long.

So every 2 seconds there came 10 new values in the buffer.

What I need to do is taking the 3 highest values.

How can I know wich values to take, how can I know wich values are the highest in other words ?

http://en.wikipedia.org/wiki/Sorting_algorithm Choose one, implement in S7, use against your data... And that's all

I'd suggest selection sort method.

hmmmm

j [url="http://nl.wikipedia.org/wiki/Quicksort#De_basis" said:

http://nl.wikipedia.org/wiki/Quicksort#De_basis[/url]
acekd]http://en.wikipedia.org/wiki/Sorting_algorithm Choose one, implement in S7, use against your data... And that's all

I'd suggest selection sort method.

Click to expand...

All these examples are in Java or C

I understand SCL, but Java and C not well.

But I now know that I need s SORT ALGORITM.

Anyone who can translate an example program (QUICKSORT for example) of that site in SCL or STL ?

Thanks in forward

Quicksort is one of faster methods but only when you have enough of data to be sorted. It is more complicated and not worth implementing for such small quantity. Personally I'd just use modified bubble sort (3-passes are enough : find largest of 10, you have 9 left, find largest in those 9 and you have 8 ints left, find biggest in 8 and you are done)

thanks

thanks

Found code of the bubble in the pascal language, allmost the same as SCL


edit] Pascal
Procedure BubbleSort( Var Data : IntArray; Count : integer; First : integer; Last : integer; Acend : boolean; Var Succ : integer );var i, temp, s_begin, s_end, numsort : integer; sorted : boolean;Begin { initialize for full array sort } s_begin := STARTINTARRAY; s_end := STARTINTARRAY + count - 1 ; numsort := Count; Succ := 0; { assume success } { check for a subset sort; check parameters for correctness } if (Count = 0) then Begin If (First < STARTINTARRAY) then Begin { error: sort start index too low } Succ := 1; Exit; End; If (Last > MAXINTARRAY) then Begin { error: sort end index too high } Succ := 2; Exit; End; if (Last < STARTINTARRAY) then Begin { error: sort end index too low } Succ := 3; Exit; End; s_begin := First; s_end := Last; numsort := Last - First + 1; End; If numsort <= 1 then Exit; { only one element, so exit } If Acend then Begin { do the ascending sort } Repeat sorted := true; { flag default is true } For i := s_begin to s_end -1 do if (Data < Data[i+1]) then Begin { swap contents of Data and Data[i+1] } temp := Data; Data := Data[i+1]; Data[i+1] := temp; { set flag to indicate a swap occured; i.e., sort may not be completed } sorted := false; End; Until sorted; End Else Begin { do the descending sort } Repeat sorted := true; { flag default is true } For i := s_begin to s_end -1 do if (Data < Data[i+1]) then Begin { swap contents of Data and Data[i+1] } temp := Data; Data := Data[i+1]; Data[i+1] := temp; { set flag to indicate a swap occured; i.e., sort may not be completed } sorted := false; End; Until sorted; End;End;

hmzz

Anyone who can help writing it in SCL ?

Hi,

Seeing this is a fifo buffer and only one new value is added, I'd take different approach:

Take new value, compare it against the 3 highest. If higher then one of them, then if neccesary shift other(s) down (only needed if highest2) and then replace with new value (first shift then replace to avoid loss of data..)

Would be easy to do in STL and alot less complicated. You can do this cyclicly or on every new addition to the FIFO (every 0.2sec)

Just my 2cts.

Jeebs

Do you just need to know the highest three values, or do you need to know where they are in the FIFO?

This is what I have yntil now in SCL

Some SCL problems

Jeebs said:

Hi,

Seeing this is a fifo buffer and only one new value is added, I'd take different approach:

Take new value, compare it against the 3 highest. If higher then one of them, then if neccesary shift other(s) down (only needed if highest2) and then replace with new value (first shift then replace to avoid loss of data..)

Would be easy to do in STL and alot less complicated. You can do this cyclicly or on every new addition to the FIFO (every 0.2sec)

Just my 2cts.

Jeebs

Click to expand...

The problem here is, how do you do this when one of those highest may move out of the FIFO, you would have to compare the number being moved out with the three you have and then what do you replace it with if it comes out?

Maybe search the FIFO!!

Error Free

It's error free now, I found all the mistakes

I'll test it

PeterW said:

The problem here is, how do you do this when one of those highest may move out of the FIFO, you would have to compare the number being moved out with the three you have and then what do you replace it with if it comes out?

Maybe search the FIFO!!

Click to expand...

Somehow I fail to see the problem you are trying to describe.

Working Code

Guys, It works, thank you all !!!

Jeebs said:

Somehow I fail to see the problem you are trying to describe.

Click to expand...

Maybe I haven't grasped what you were saying, but its a FIFO a length of 10, which means on the 11th pulse, the first value leaves the FIFO.

What if that 1st value was one of the top 3, then the top 3 would have to be re-adjusted and the next highest brought into the top 3.

In your explanation I cannot see where you handle this.

I assume the listed routine is called on each entry of data into the FIFO. It doesn't modify the original (unless the calling routine sets 'Data_In' and 'Data_Out' to point to the same array.) It just seems a waste to sort the entire array when it will only require the first three passes.