How to find difference without previous

[former_member225386]

Hi All,

I need your help to resolve the below error will using previous function in group level.

Value	log	Difference using Previous
A1	B1
A2	B2	B1-B2
A3	B3	B2-B3
A4	B4	B3-B4
A5	B5	B4-B5
A6	B6	B5-B6
A7	B7	B6-B7
A8	B8	B7-B8
		need to find stddev

In the above table those are in black has been done and the red one need to be done.

This table is based on group level while I'm using the stddev for the Difference using Previous column I'm getting an error THIS FIELD CANNOT BE SUMMARIZED.

Could you please help me out that whether is there any way to find difference without using previous or next function.

[abhilash_kumar · Accepted solution]

Hi Ramesh,

The stddev() function also accepts an array of numbers.

Try this:

1) Create a formula with this code and place it on the section beside the 'Difference using previous' column:

WhilePrintingRecords;

NumberVar array arr;

numbervar i;

i := i + 1;

redim preserve arr[i];

arr[i] := previous({Log}) - {Log};

"";

2) Create another formula and place this on the Footer:

WhilePrintingRecords;

NumberVar array arr;

Stddev(arr);

3) If you need to reset the array for each group, just create a reset formula with this code and place it on the Group Header:

WhilePrintingRecords;

NumberVar array arr := 0;

-Abhilash

[former_member225386 · Accepted solution]

Hi Abhilash,

Thank you!

Again im facing one problem the stddev returing only right values for first group. from secound group onwords the values of stddev is returning wrong value.

for an cross check could you please let me know the exact position to place the reset formula in report.

[abhilash_kumar · Accepted solution]

Hi Ramesh,

The third formula above should be placed on the Group Header #1.

-Abhilash

[former_member225386 · Accepted solution]

Hi Abhilash,

Thank you!

Done the same and confussed to see that the reset formula specifed below is not reseting the values in group level.

To confirm that I tried to print the "i" values used in Difference formula the value of the "i" is continuing even after the group changed.

WhilePrintingRecords;

NumberVar array arr := 0;

Please help me out in this.

Regards,

Ramesh Jothimani

[abhilash_kumar · Accepted solution]

I'm sorry, you also need to reset 'i';

WhilePrintingRecords;

NumberVar array arr := 0;

numbervar i := 0;

-Abhilash

[former_member225386 · Accepted solution]

Hi Abhilash,

Will this formula calculate stddev based on group level?

WhilePrintingRecords;

NumberVar array arr;

Stddev(arr);

As per my report it is of returing the Standard deviation values for entire values of difference(without considering group level).

Thanks!

Regards,

Ramesh Jothimani

[abhilash_kumar · Accepted solution]

What do you mean by group level?

The formula evaluates on the details section and hence looks at 'difference' at each row. The Stddev is printed at the Group level by taking into account all differences for that group.

Could you post a screenshot of what you're trying to do and how the report is structured?

-Abhilash

[former_member225386 · Accepted solution]

Hi Abhilash,

Thank you for your quick responce.

Please find the attachment of the expected outcome and report structure.

[abhilash_kumar · Accepted solution]

Ok, see if this helps:

Modify the first formula above to:

WhilePrintingRecords;

Numbervar x := x + 1;

NumberVar array arr;

numbervar i;

If x <> 1 then

(

     i := i + 1;

     redim preserve arr[i];

     arr[i] := previous({Log}) - {Log};

     "";

);

Modify the reset formula on the Group Header to:

WhilePrintingRecords;

NumberVar array arr := 0;

Numbervar x := 0;

Numbervar i := 0;

-Abhilash

[former_member225386 · Accepted solution]

Hi Abhilash

Sorry for the late reply I were OOO.

Its workign fine thanks a lot for you help.

[former_member225386 · Accepted solution]

Hi Abhilash,

Again now im getting an new error while im selecting more than 52 weeks in the prompt.

Could you please help me on this.

[abhilash_kumar · Accepted solution]

Please close this thread and post this new issue as a separate discussion per SCN's rules.

Also post a screenshot of the full formula editor window with the panel on the left expanded.

-Abhilash