How to calculated logirothemic regression manually using DAX?

[Anonymous]

How to calculate logarithemic regression : Y = a + b * ln (X)  ?

@MFelix 

[Anonymous]

@MFelix, @v-kelly-msft  Below code is used for log regression 

LogTrend-A-MB = 
VAR Known =
FILTER (
SELECTCOLUMNS (
CALCULATETABLE ( VALUES ( ConsumptionDate[DateNumber] ), ALLSELECTED (ConsumptionDate) ),
"Known[X]", 'ConsumptionDate'[DateNumber],
"Known[Y]", PatientsNormalized[A-MB]
),
AND ( NOT ( ISBLANK ( Known[X] ) ), NOT ( ISBLANK ( Known[Y] ) ) )
)
VAR Count_Items =
COUNTROWS ( Known )
VAR Sum_X =
SUMX ( Known, Known[X] )
VAR Sum_X2 =
SUMX ( Known, Known[X] ^ 2 )
VAR Sum_Y =
SUMX ( Known, Known[Y] )
VAR Sum_XY =
SUMX ( Known, Known[X] * Known[Y] )
VAR Average_X =
AVERAGEX ( Known, Known[X] )
VAR Average_Y =
AVERAGEX ( Known, Known[Y] )
VAR Slope =
DIVIDE (
Count_Items * Sum_XY - Sum_X * Sum_Y,
Count_Items * Sum_X2 - Sum_X ^ 2
)
VAR Intercept = Average_Y
- Slope * Average_X
RETURN
SUMX( DISTINCT ( ConsumptionDate[DateNumber] ),
LN(Intercept + Slope * ConsumptionDate[DateNumber])
)

[v-kelly-msft]

Hi @Anonymous ,

You can use "LOG10" function in dax expression:

Y=a+b*LOG10(X)

Here is the link for reference:

https://docs.microsoft.com/en-us/dax/log10-function-dax

Best Regards,
Kelly

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[Anonymous]

Hi @v-kelly-msft ,

I calculated using below dax but same value repeated (i.e returned same value for every row).

Log A-MB = 
VAR Known =
FILTER (
SELECTCOLUMNS (
CALCULATETABLE ( VALUES ( ConsumptionDate[DateNumber] ), ALLSELECTED (ConsumptionDate) ),
"Known[X]", 'ConsumptionDate'[DateNumber],
"Known[Y]", PatientsNormalized[A-MB]
),
AND ( NOT ( ISBLANK ( Known[X] ) ), NOT ( ISBLANK ( Known[Y] ) ) )
)
VAR Count_Items =
COUNTROWS ( Known )
VAR Sum_X =
SUMX ( Known, Known[X] )
VAR Sum_X2 =
SUMX ( Known, Known[X] ^ 2 )
VAR Sum_Y =
SUMX ( Known, Known[Y] )
VAR Sum_XY =
SUMX ( Known, Known[X] * Known[Y] )
VAR Average_X =
AVERAGEX ( Known, Known[X] )
VAR Average_Y =
AVERAGEX ( Known, Known[Y] )
VAR Slope =
DIVIDE (
Count_Items * Sum_XY - Sum_X * Sum_Y,
Count_Items * Sum_X2 - Sum_X ^ 2
)
VAR Intercept = Average_Y
- Slope * Average_X
RETURN
SUMX( DISTINCT ( ConsumptionDate[DateNumber] ),
Intercept + Slope * LOG10(ConsumptionDate[DateNumber])
)

 Please help me on this. 

[v-kelly-msft]

Hi @Anonymous,

What does the below expression represent for?

 FILTER (
        SELECTCOLUMNS (
            CALCULATETABLE (
                VALUES ( ConsumptionDate[DateNumber] ),
                ALLSELECTED ( ConsumptionDate )
            ),
            "Known[X]", 'ConsumptionDate'[DateNumber],
            "Known[Y]", PatientsNormalized[A-MB]
        )

Does there any error return?

Best Regards,
Kelly

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[Anonymous]

That code block is used to get idividual rows of the table.

No errors code is working as expected.

REF : https://xxlbi.com/blog/simple-linear-regression-in-dax/

[v-kelly-msft]

Hi @Anonymous ,

So your issue is solved now?

Best Regards,
Kelly

Did I answer your question? Mark my post as a solution!

[Anonymous]

No @v-kelly-msft still waiting..

[MFelix]

Hi @Anonymous ,

I'm calling out to @Greg_Deckler because he has done a lot of examples for this type of situations not sure if he has done it for logotithemic.

@Greg_Deckler did you do Logarithicm on your extense DAX calculations?