Find x-axis value related to maximum value in y-axis ; SPOTFIRE - spotfire

I am trying to find x-axis(frequency) value that corresponds to max(y-axis)(amplitude).
But it is bit complicated the csv have 3 columns :
first - S/N
second - x-axis (frequency)
third - y-axis (amplitude)
the graph type is line and the "color by" is S/N column.
I tried to this IF statement:
If([signal_power [dBm]]]=Max([signal_power [dBm]]]),Max([signal_power [dBm]]]),-1000)
the to filter out all the "-1000" which will leave me only with the x-axis value that corresponds to the max(y-axis).
the problem is that the IF searches all over the S/N column.
thanks

Use (Max([signal power]) Over ([S/N])) instead max only, this will calculate max for each S/N value.
Tip: Instead of -1000 it's more elegant to use nul.

Related

EXCEL - Dual VLOOKUP and Interpolation

I have a table on Excel with data as the following:
Meaning, I have different JPH based on the %SMALL unit and the number of active stations.
I need to create a matrix like the following (with %SMALL on horizontal and STATIONS on vertical axes):
And the formula for each cell should:
Take the input of Stations (column "B")
Check, for that specific Stations number, the amount of data on the other table (like make a filter on STATIONS for the specific number)
Perform an VLOOKUP for checking the JPH based on the %SMALL value on row 2
Interpolate for the exact JPH value, if not found on table
For now, I was able to create the last part (the VLOOKUP and the interpolation), with the following:
=IFERROR(VLOOKUP(C2;'EARLY-STATIONS'!$F:$H;3;FALSE);AVERAGE(OFFSET(INDEX('EARLY-STATIONS'!$H:$H;MATCH(C2;'EARLY-STATIONS'!$F:$F;1));0;0;2;1)))
The problem I'm facing is than with this, the calculation is not checking the number of stations, so the Iteration is not accurate.
Unfortunately I cannot use VBA macros to solve this.
Any clue?
This is an attempt because more clarity is needed in terms of all possible scenarios to consider, based on different input data and how to understand the "extrapolation" process. This approach understands as extrapolation the average of two values (lower and greater), but the idea can be customized to any other way to calculate it. Per tags listed in the question I assume there is no Excel version constraint. This is O365 solution:
=LET(sm, A2:A10, st, B2:B10, jph, C2:C10, smx, F1:J1, sty, E2:E4, NULL, "",
GETLk, LAMBDA(x,y,mode, FILTER(jph, (st=y)
* (sm = INDEX(sm, XMATCH(x, sm, mode))), NULL)),
GET, LAMBDA(x,y, LET(f, FILTER(jph, (jph=GETLk(x,y, 1))
+ (jph=GETLk(x,y, -1)), NULL), IF(#f=NULL, NULL, AVERAGE(f)))),
HREDUCE, LAMBDA(yi, DROP(REDUCE("", smx, LAMBDA(ac,x,
HSTACK(ac, GET(x, yi)))),,1)),
DROP(REDUCE("", sty, LAMBDA(ac,y, VSTACK(ac, HREDUCE(y)))),1))
The above formula spills the entire result, I don't think for this case you can use a LOOKUP-like function.
Here is the output:
The highlighted cells where the average is calculated.
Explanation
The main idea is to use DROP/REDUCE/HSTACK/VSTACK pattern to generate the grid. Check my answer to the following question: how to transform a table in Excel from vertical to horizontal but with different length on how to apply it.
We use two user LAMBDA functions to abstract some calculations:
GETLk(x,y,mode), filters jph name based on %SMALL and Stations columns values, based on input values x (x-axis value from the grid), y (y-axis value form the grid) respectively. The third input argument mode, is for doing the approximate search in XMATCH (1-next largest, -1 next smallest). In case the value exist in the input table, XMATCH returns the same value in both cases.
GET(x,y) has the logic to find the value or if the value doesn't exist to calculate the average. It uses the previous LAMBDA function GETLk. We filter for jph values that match the input values (x,y), but we use an OR condition in the FILTER (+), to select both lower or greater values. If the value exist, returns just one value otherwise two values are returned by FILTER (f). Finally if f is not empty we return the average, otherwise the value we setup as NULL.
HREDUCE: Concatenate the result by columns for a given row of the grid. Check the referred question for more information about it.

What's the logic behind PERCENTILE.INC Excel function?

I would like to know how does Excel think to calculate the values on the function PERCENTILE.INC. I'm making some studies on Percentile and Quartile, I got the below results:
How does Excel think to calculate the values on column F?
Here's the formulas I'm using:
=PERCENTILE.INC(B2:B21; 0,75) ==> F2
=PERCENTILE.INC(B2:B21; 0,50) ==> F3
=PERCENTILE.INC(B2:B21; 0,25) ==> F4
=PERCENTILE.INC(B2:B21; 0,00) ==> F5
Short answer - the position of a given percentile when the data is sorted in ascending order, using percentile.inc, is given by
(N-1)p+1
where p is the required percentile as a fraction from 0 to 1 and N is the number of points.
If this expression gives a whole number, you take the value at this position (e.g. percentile zero gives 1, so its value is exactly 22). If it's not a whole number, you interpolate between the value at the position given by the whole number part (e.g. for p=0.25 it's 5 and the value at this position is 52) and the value at the position one higher (in this case position 6 so the number is 55), then multiply the difference of the two values (3) by the fraction part (0.75) giving you 2.25 and finally add this to the lower of the two values giving you 54.25. A shorter way of saying this is that you go a quarter of the way between the two nearest values. So you have:
If you wished to show the logic as an Excel formula, you could implement the expression shown here on the right (where h, in the second column of the table, is the position calculated from the formula above and x is the value at that position)
like this:
=LET(p,J3,
range,I$2:I$21,
N,COUNT(range),
position,(N-1)*p+1,
lower,FLOOR(position,1),
fraction,MOD(position,1),
upper,CEILING(position,1),
lowerValue,INDEX(range,lower),
upperValue,INDEX(range,upper),
difference,upperValue-lowerValue,
lowerValue+fraction*difference)

Percentage Over Column Total Calculation

I am trying to do a cross table with a column that calculates the percentage the column total (third column from the left). I've been trying to follow some examples found in my Google searches but can't seem to get it to work.
I tried to insert this custom expression in my subsets:
Count() THEN [Value] / Sum([Value]) OVER (All([Axis.Rows]))
But I get this error: The expression is not valid after 'THEN' on line 1 character 9.
If someone still trying to do this you can do this :
Count() then Sum([Value]) Over (AllPrevious([Axis.Rows])) / Sum([Value]) OVER (All([Axis.Rows])) as [Cumulative Sum]
That will give you this result :
Where you have "(Column Names)" in Horizontal, [country] in Vertical axis and the sum and cumulative sum in the Cell Values.

Using tbl.Lookup to match just part of a column value

This question relates to the Schematiq add-in for Microsoft Excel.
Using =tbl.Lookup(table, columnsToSearch, valuesToFind, resultColumn, [defaultValue]) the values in the valuesToFind column have a consistent 3 characters to the left and then varying characters after (e.g. 908-123456 or 908-321654 - i.e. 908 is always consistent)
How can I tell the function to lookup the value based on the first 3 characters only? The expected answer should be the sum of the results of the above, i.e. 500 + 300 = 800
tbl.Lookup() works by looking for an exact match - this helps ensure it's fast but in this case it means you need an extra step to calculate a column of lookup values, something like this:
A2: =tbl.CalculateColumn(A1, "code", "x => LEFT(x, 3)", "startOfCode")
This will give you a new column that you can use for the columnsToSearch argument, however tbl.Lookup() also looks for just one match - it doesn't know how to combine values together if there is more than one matching row in the table, so I think you also need one more step to group your table by the first 3 chars of the code, like this:
A3: =tbl.Group(A2, "startOfCode", "amount")
Because tbl.Group() adds values together by default, this will give you a table with a row for each distinct value of startOfCode and the subtotal of amount for each of those values. Finally, you can do the lookup exactly as you requested, which for your input table will return 800:
A4: =tbl.Lookup(A3, "startOfCode", "908", "amount")

Scatter plot for variable number of rows and specific columns

I want to create an automated scatter plot. This is the first example table based on the step size I end up measuring A, B, C, D for a specific frequency. In this scatter plot I created manually you can see I want to plot C v/s A for a particular frequency.
But I need to do this automatically as based on the step size the number of row can change. Here, since the step size decreased the number of samples increased, and now the scatter plot needs to update number of A and C values it plots.
Is there a formula I can use without using any macros?
The relation between the step size and frequency is (number of samples of a single frequency = (360/step size)) so for a step size of 60 you will have in reality six entries of frequency 100 and six of 200 .
You can use formulas to define chart ranges if you hide the formulas in named ranges. Combine that with the fact that #N/A values are not plotted and you can get this to work without VBA.
For your example graph you could define two names ranges as follows:
Name: A_100
Refers To: =IF(Sheet1!$E$3:$E$100=100,OFFSET(Sheet1!$A$3,0,0,360/Sheet1!$B$1,1),NA())
and
Name: C_100
Refers To: =IF(Sheet1!$E$3:$E$100=100,OFFSET(Sheet1!$C$3,0,0,360/Sheet1!$B$1,1),NA())
Then set the X and Y axis of the chart to SheetName!A_100 and SheetName!C_100
The if statement filters out all the points not at frequency 100, if you have a formula for selecting the frequency replace "Sheet1!$E$3:$E$100=100" with that.
The offset function takes the first cell in the column and expands the number of rows according to your 360/step size formula.

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