IMLN

In my recent quest to create or catalog as many DAX equivalents for Excel functions, was able to leverage COMPLEX, IMAGINARY and IMREAL into IMLN.

IMLN = 
    VAR __Real1 = [IMREAL]
    VAR __i1 = [IMAGINARY]
    VAR __Real = LN( SQRT( POWER(__Real1,2) + POWER(__i1,2) ) )
    VAR __i = ATAN(DIVIDE(__i1,__Real1,0))
    VAR __suffix = IF(MAX([suffix])="","i",MAX([suffix]))
RETURN
    SWITCH(TRUE(),
        __Real = 0 && __i = 1, __suffix,
        __Real = 0 && __i = -1, "-" & __suffix,
        __Real = 0, __i & __suffix,
        __i = 0, __Real & "",
        __i < 0 && __i = -1, __Real & "-" & __suffix,
        __i < 0, __Real & "-" & ABS(__i) & __suffix,
        __i = 1, __Real & "+" & __suffix,
        __Real & "+" & __i & __suffix
    )

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