icCube - InterpolateRGBColors based on min & max values? - colors

Question

I understand that InterpolateRGBColors function is returning a color by position of value between 0 and 1... So its seems to be doable only with percentages, not numbers...
Is there a way to have the same functionality, but based on the min and max values returned in a set ?
What I want is to attribute colors to my measure but in a range of min([Measures].[NbSejours]) to max([Measures].[NbSejours]) ( not 0 to 1)...
WITH
MEMBER [Measures].[color] AS
InterpolateRGBColors(
[Measures].[NbSejours]
,rgb(176,224,230)
,rgb(135,206,235)
,rgb(0,191,255)
,rgb(100,149,237)
,rgb(0,0,255)
,rgb(0,0,139)
,rgb(25,25,112)
), BACK_COLOR=currentCellValue()
SELECT
{
{[Measures].[NbSejours]}
,[Measures].[color]
} ON COLUMNS
,{
NonEmpty
(
[Etablissement].[Etablissement].[Etablissement].ALLMEMBERS
,[Measures].[NbSejours]
)
} ON ROWS
FROM
(
SELECT
{{[Periode].[Periode].[All-M].&[2013]}} ON 0
FROM [Cube]
)
CELL PROPERTIES
STYLE
,CLASSNAME
,VALUE
,FORMATTED_VALUE;
Is there a way to do that ?

Answer 1

InterpolateRGBColors expect a numerical between 0 and 1 for interpolation. So we need to scale our measure to ensure we get the right colors.
There is an example in our live demo , here.
What we need is to scale [Measures].[NbSejours] between 0,1. There are two no documented function in icCube DistributionFlat & DistributionRank.
A non efficient version
WITH
SET [AxisX] AS NonEmpty([Etablissement].Etablissement].Etablissement].ALLMEMBERS,[Measures].[NbSejours])
FUNCTION distr(x_) as DistributionFlat( [AxisX], [Measures].[NbSejours], x_ )
MEMBER [Measures].[color] AS
InterpolateRGBColors(
distr([Measures].[NbSejours])
,rgb(176,224,230)
,rgb(135,206,235)
,rgb(0,191,255)
,rgb(100,149,237)
,rgb(0,0,255)
,rgb(0,0,139)
,rgb(25,25,112)
), BACK_COLOR=currentCellValue()
....
Once I got a bit of time I'll write a version using Vectors (here and here) that is more performant as in the example above we calculate every time the values for the set.
Hope it helps

Answer 2

I don'r know icCube so the following might not work, even though I have used standard functions. As #George commented you can use the standard RANK function to find each members relative position.
You will need to feed that value into the definition of [Measures].[color]...
WITH
SET [estMembersOrdered] AS
ORDER(
[Etablissement].[Etablissement].[Etablissement].ALLMEMBERS
,[Measures].[NbSejours]
,BDESC
)
MEMBER [Measures].[rnkEtablissement] AS
RANK(
[Etablissement].[Etablissement].CURRENTMEMBER
, [estMembersOrdered]
)
MEMBER [Measures].[color] AS
InterpolateRGBColors(
[Measures].[NbSejours]
,rgb(176,224,230)
,rgb(135,206,235)
,rgb(0,191,255)
,rgb(100,149,237)
,rgb(0,0,255)
,rgb(0,0,139)
,rgb(25,25,112)
), BACK_COLOR=currentCellValue()
SELECT
{
{[Measures].[NbSejours]}
,[Measures].[color]
,[Measures].[rnkEtablissement]
} ON COLUMNS
,{
NonEmpty
(
[Etablissement].[Etablissement].[Etablissement].ALLMEMBERS
,[Measures].[NbSejours]
)
} ON ROWS
FROM
(
SELECT
{{[Periode].[Periode].[All-M].&[2013]}} ON 0
FROM [Cube]
)
CELL PROPERTIES
STYLE
,CLASSNAME
,VALUE
,FORMATTED_VALUE;