How to create an excel formula for the above equation?
Eg. N = 10, P = 9.4
Thanks!
Try the following user defined function:
Public Function Zigma(N As Long, p As Double) As Double
Dim i As Long
Zigma = N
For i = 1 To N - 1
Zigma = Zigma - (i / N) ^ p
Next i
End Function
This allows you to avoid array formulas.
Here it is as an excel formula:
=A1-SUMPRODUCT((ROW(A1:INDEX(A:A, A1-1))/A1)^A2)
Related
I have a list of words and I would like to find all symmetric words and some how put value 1 for each of them (see the picture).
This does the trick:
=1*(A1=CONCAT(MID(A1,LEN(A1)-SEQUENCE(1,LEN(A1),0),1)))
It reads the string in a cell backwards using MID and SEQUENCE, and compares the CONCAT result with the original to see if it is the same, i.e. the string is symmetric.
Multiplying by 1 forces the Boolean into an integer.
With VBA. This assumes that a single character is symmetric:
Public Function Sym(s As String) As Long
Dim L As Long, L2 As Long
Dim p1 As String, p2 As String
L = Len(s)
L2 = Int(L / 2)
Sym = 0
If L Mod 2 = 0 Then
' even
p1 = Mid(s, 1, L2)
p2 = StrReverse(Mid(s, L2 + 1))
If p1 = p2 Then
Sym = 1
End If
Else
' odd
p1 = Mid(s, 1, L2)
p2 = StrReverse(Mid(s, L2 + 2))
If p1 = p2 Then
Sym = 1
End If
End If
End Function
This will handle both an even or odd number of characters.
EDIT#1:
Simply:
Public Function Sym(s As String) As Long
Sym = 0
If s = StrReverse(s) Then Sym = 1
End
With Microsoft365, try:
Formula in B1:
=EXACT(A1,CONCAT(MID(A1,SEQUENCE(LEN(A1),,LEN(A1),-1),1)))
Formula in C1:
=--EXACT(A1,CONCAT(MID(A1,SEQUENCE(LEN(A1),,LEN(A1),-1),1)))
If you are working in a version without CONCAT() it will get significatly more verbose, but still possible:
=SUMPRODUCT(--EXACT(MID(A1,ROW(A$1:INDEX(A:A,LEN(A1))),1),MID(A1,(LEN(A1)+1)-ROW(A$1:INDEX(A:A,LEN(A1))),1)))=LEN(A1)
This, again, can be wrapped to return either 1 or 0 if you prefer that over the boolean results:
=--(=SUMPRODUCT(--EXACT(MID(A1,ROW(A$1:INDEX(A:A,LEN(A1))),1),MID(A1,(LEN(A1)+1)-ROW(A$1:INDEX(A:A,LEN(A1))),1)))=LEN(A1))
How to create an excel formula for the above equation?
Eg. N = 10, P = 9.4
Thanks!
Try the following user defined function:
Public Function Zigma(N As Long, p As Double) As Double
Dim i As Long
Zigma = N
For i = 1 To N - 1
Zigma = Zigma - (i / N) ^ p
Next i
End Function
This allows you to avoid array formulas.
Here it is as an excel formula:
=A1-SUMPRODUCT((ROW(A1:INDEX(A:A, A1-1))/A1)^A2)
I am currently working with arrays and loops, and am trying to write a function that will output an n by m array (a matrix) with the numbers {1, 2, 3, ... , n*m}
I am trying to learn some basic VBA code, this is purely for educational purposes.
This is what I have come up with:
Function createMatrix(n, m)
Dim matrix(1 To n, 1 To m) As Integer
x = 1
For i = 1 To n
For j = 1 To m
matrix(i, j) = x
x = (x + 1)
Next j
Next i
createMatrix = matrix
End Function
It returns #VALUE. I cannot understand why.
I got it to work at one point (creating a 3x3 matrix) by making it a function that did not take any variables and then initializing the matrix array by
Dim matrix(1 to 3, 1 to 3) As Integer
replacing n and m in the for loops with 3s.
So I guess the variables n and m are causing the problems, but don't know why.
Array declarations must be static (where the bounds are defined by a hardcoded value); however you can resize them dynamically using the ReDim statement.
' Declare an array.
' If you want to size it based on variables, do NOT define bounds.
Dim matrix() As Integer
' Resize dynamically.
ReDim maxtrix(n, m)
Note that when you ReDim, all values will be lost. If you had values in matrix that you wanted to keep, you can add the Preserve keyword:
ReDim Preserve matrix(n, m) ' Keep any existing values in their respective indexes.
You first need to declare array as dynamic array and then redim it to your dimension.
Function createMatrix(n, m)
Dim matrix() As Integer
ReDim matrix(1 To n, 1 To m) As Integer
x = 1
For i = 1 To n
For j = 1 To m
matrix(i, j) = x
x = (x + 1)
Next j
Next i
createMatrix = matrix
End Function
So I'm calculating basic statistics in my worksheet and it includes code such as:
xxx = Application.worksheetfunction.average(etc etc etc
yyy = Application.worksheetfunction.min(etc etc etc
zzz = Application.worksheetfunction.max(etc etc etc
My question: Is there an RMS equivalent function where I can simply plug it in place of where I have 'average, min, max' functions in that code? And if there isn't then what would be the most efficient means to code in to find RMS solutions?
I hope I've stated the goal clearly enough. I'm curious as to whether or not there is a predefined RMS function for VBA or whether or not I've got to create some sort of user defined function? ~ That of which I'm fairly new to as well so if there isn't a simple line of code to write for this, I'll have to do more reading on UDF's.
EDIT:
I've got around 30,000 rows, and for simplicity's sake: imagine two columns. Column A has the year i.e. 1941 or anything else through 2008. Column B is a numeric value. I'm just trying to put code together that gives decade summaries of Average, Min, Max, and the RMS values.
You can do the average with
=SQRT(SUMSQ(A:A)/COUNTA(range))
or in VBA:
r = (Application.WorksheetFunction.SumSq(Range("A:A")) / Range("A:A").Count) ^ (1 / 2)
A VBA function that accepts arrays (any rank) and ranges with multiple areas (a discontinuous range like A4:B6,C11:D15), or even a union of ranges in a formula. It skips non number datatypes (including dates, boolean, blanks etc).
You can use it in VBA code, or as a UDF in a worksheet formula such as:
"=RMS(A1:A10)" (basic usage)
"=RMS(A1:A10,C1:C10)" (multiple ranges (or arrays for that matter))
"{=RMS({1,2,3,4})}" (array formula entered with Ctrl+shift+enter)
Function RMS(ParamArray args()) As Double
Dim arg, arr, area As Range, ss As Double, n As Long
For Each arg In args
If TypeOf arg Is Range Then
For Each area In arg.Areas
arr = area.value
If VarType(arr) < vbArray Then
queryRmsElements Array(arr), ss, n
Else
queryRmsElements arr, ss, n
End If
Next area
ElseIf VarType(arg) > vbArray Then
queryRmsElements arg, ss, n
Else
Err.Raise 1, "RMS", "Invalid Argument"
End If
Next arg
RMS = (ss / n) ^ 0.5
End Function
Private Sub queryRmsElements(ByRef elements, ByRef ss As Double, ByRef n As Long)
Static element As Variant
'Enumerate to cover rank > 1 (vs. Iterate)
For Each element In elements
Select Case VarType(element)
Case VbVarType.vbByte, _
VbVarType.vbCurrency, _
VbVarType.vbDecimal, _
VbVarType.vbDouble, _
VbVarType.vbInteger, _
VbVarType.vbLong, _
VbVarType.vbSingle
ss = element ^ 2 + ss
n = n + 1
Case Else
End Select
Next element
End Sub
This one worked for me:
Function RMS(Intervalo As Range)
Dim SomaQ As Double
Dim Tamanho As Integer
SomaQ = 0
Tamanho = Intervalo.Count
SomaQ = Application.WorksheetFunction.SumSq(Intervalo)
RMS = Sqr(SomaQ / Tamanho)
End Function
I am trying to find the largest prime divisor of a number x. When x is smaller than 1billion my code works but when it is greater than 1billion it gives an overflow error and debugging highlights the line with Mod in it.
Sub Largest_Divisor()
Dim x As Double
Dim Q As Integer
Q = 0
Dim L() As Double
x = 999999999#
Dim i As Double
For i = 775145 To 3 Step -2
If x Mod i = 0 Then
If IsPrime(i) Then
ReDim Preserve L(Q) As Double
L(Q) = i
Q = Q + 1
End If
End If
Next i
MsgBox (Application.Max(L))
End Sub
I suspect it is when x is larger than about 2 billion, 2,147,483,648 to be precise, that you have trouble.
That is because as per the documentation of mod, at most a long is returned, which ranges in value from -2,147,483,648 to 2,147,483,647 as a 32-bit signed value. It is not explicitly stated in the help documentation, but the arguments of mod are probably coerced to long as well.
A good work around can be to use this function:
Function Modulus(int1 As Double, int2 As Double) As Double
' This function will return int1 Mod int2. It is useful when |int1| exceeds
' 2,147,483,647 as the VBA Mod function will then break.
'
Dim myInt As Integer
myInt = Int(int1 / int2)
Modulus = int1 - (myInt * int2)
Return Modulus
End Function