I have a VBA function that calculates polynomial coefficients for a series of data pairs. One selects the range of cells that the coefficients are to be stored in, and enters the polynomial formula:
{POLFIT(Xa, Ya, N)}
Where Xa is the array of ordinate values, Ya is the array of data values, and N is the polynomial order to be fit.
It is obvious that one needs to select at least N+1 cells when the array funtion is typed in. But, it is easy to select too few cells.
I am looking for a way to test whether enough cells were selected for the range formula: The function declaration is
Function POLFIT(Xa, Ya, N As Integer) As Variant
Various means I have tried to count POLFIT do not return the correct value.
i have a function in a cell (that works) to extract coefficients from a range of cells in a workbook:
VB: =INDEX(LINEST(CP25:CP27,CQ25:CQ27^{1,2}),1)}
i have variables for cp25:cp27 and cq25:cq27 already defined in my vba code. the values for these in the case i am working on are as follows (returns 110.5):
1) how to do this function in VBA only - this is part of a UDF and cannot have any helper cells 2) how to refer to 560,570,580 as a 'range'. is there a way to put these six variables into my ranges for later processing?
All of the google searches i have deal only with linear regression, taking from existing graphs, or say to just use the function i have above.
I have tried
VB:
Var = Application.WorksheetFunction.LinEst(Sheets("references").Range("CP25:CP27"), Sheets("references").Range("CQ25:CQ27^{1,2}"), 1) [COLOR=#333333][/COLOR]
but return #value! errors. when i remove the ^{1,2} portion, i do return a value but it is incorrect (returns 160), what is the correct syntax for adding in the ^{1,2}? if you do that would be fantastic, but brings me back to issue #2 in that i need to refer to my variables in the vba code and not this range (as they will eventually be going away).
I have quite a number of 4th degree polynomials and attempting to extract the variables from every equation. I used the formula below (from another thread);
I'm trying to do a binomial distribution summation as part of a VBA function, and have been using the Application.WorksheetFunction.BinomDist function, which works fine until the numbers get large - the binomial coefficients used in the calculation end up being larger than can be held in a double floating-point number in VBA, so excel can't handle it. The final result of the calculation is a probability, so it's not a huge number! I was wondering if anyone knows an alternate way of calculating binomial probabilities which avoid any huge number intermediates.
to getting accurate regression coefficients from a dataset with *small* (standard) numbers, which contains centered predictors. More specifically, I have a dataset with 18 observed data points containing a criterion (y), a centered predictor variable (x), another centered predictor variable (z), and the interaction of the two centered predictor variables (xz). This multiple regression equation is structured to test for interactions between the two continuous predictor variables (x and z) as prescribed by Aiken and West (1991) in their classic book.
When I run the regression in Excel with the centered predictors, some of the regression coefficents in the output are estimated to be 0, although they are clealry *not* 0 as estimated by SPSS 14.0.2. I have spent many hours troubleshooting this problem (and searched many forums on the internet) and still do not know why this is happening.
Initially, I thought the problem might have to do with the cross-product of the centered predictors, but even just doing a regression with one of the centered predictors (for certain centered predictors) yields a regression coefficient of 0 (although it should be non-zero as per SPSS 14.0.2). When doing these multiple regressions with non-centered predictors, all regression coefficients are estimated accurately.
I was wondering if anyone had any insights on why I am experiencing these problems.... If anyone wants a sample of some test data I have used to troubleshoot these problems, you can download a file from: [url] and/or email me at (email deleted by Mod) for more datasets or questions.
Above is the polynomial equation of a trend line as shown on my chart, I have extracted the numbers into separate cells using LINEST, so now I have in cells A20 to E20 the numbers 1.083333333, -7.333333, 16.416667, -6.16667 and 4 respectively.With a "y" value of 25 how do I go about solving for a value of "x".
I've been stubbornly struggling with this on and off for a couple of weeks now and I'm not getting any closer to working it out and the websites I've found explaining the procedure all seem to go over my head by the time I get into the fourth or fifth paragraph.
I am looking for a function [or method] to calculate a polynomial curve fit. I can do it on a graph with the existing graph and chart tools, but I need to calculate it myself. Does such software exist somewhere in my Excel 2007 package, or can anyone recommend a freeware program? I am hesitant to download an unknown, un-recommended add-in.
The functions of trend lines in charts are nice, but the coefficients of the output equations are all with only one-digit for the polynomial fits. The single-digit fits by the fitting equations often result in higher deviations from what we have seen in the charts.
I also tried to use the statistical functions but it seams that I cannot get any outputs of these coefficients except for the slope of LINEST, which is not sufficient for polynomials.
I also use addins such as as regressions but cannot get anything either to help for these coefficients.
May someone tell me how to make such outputs with more digits so the equations can be more precisely fitting please?
I don't actually own Excel as yet - but I'm wondering if someone could tell me whether Excel is capable of solving what I'm told are 'polynomial equations'. An example of the sort of equation I hope to solve is: d/(1.18 + d) + d/(1.86 + d) + d/(9 + d) + d/(8.8 + d) = 2 d=? {I happen to know d = 3.65(approx) in this example btw}
I'm familiar with 2d graphs, trendlines, and regression equations. Now I have some tabular data that has 2 input variables and a result. As with my 2d data, I would like Excel to create a polynomial equation of z from the x and y inputs. Can Excel do this, or do I need a plug-in or another software package?
The array sum function works but Concatenate not. In Excel I get the formula Concatenate(H2:H3) in stead of Concatenate(H2,H3). What should I change to get the code working?
I want to create a function in a module that will read an array from sheet1 preform an operation on it then return the result to the spreadsheet in a defined amount of cells in this example 8.
In Module1:
VB: Function func1(ByRef arrayA()) Dim arrayB(8) For k = 0 To 7
[Code].....
How does the resultant arrayB get populated onto the spreadsheet?
I want to use the countif function for a certain array. The range is set by another cell which is made up out of a percentile of an entire row.
The problem is is that excel doesn't see the value it displays so i continuously get a value of 0 in the countif cell. If i fill in the range by hand, which is exactly the same range as the outcome of the percentile the countif cell does give the correct value.
So in short the problem is i guess that the countif cell does not recognize the value because this value is made up by a formula.
I am working on a Monthly Vehicle Spread Sheet. One of the outputs I am trying to achieve is an automatic calculation of Mile Per Gallon. To do this, I need to know if there is a function that will return the value of the first entry of a group of cells.
In calculating the miles per gallon, I need to subtract the first gallon amount entry of the total gallons in the month, then divide that number into the difference of the mileage in the month recorded when the vehicles fueled up.
I am trying to write a code for simulating a stock price using geometric brownian motion. I have the function part down as follows:
Public Function SimStock(Initial_Stock_Price As Double, _ Expected_Return As Double, _ Volitility As Double, _ End_Time_Days As Double, _ Number_of_Steps) As Double SimStock = Initial_Stock_Price * Exp((Expected_Return - Volitility ^ 2 / 2) * (Number_of_Steps / End_Time_Days) * NRnd2() * Sqr((Number_of_Steps / End_Time_Days))) End Function
Now what i need to do is to apply this to an array. so that when i run the sub it will simulate prices from today up to some number of days that i specify. This number of days will be equal to "End_Time_Days" which is part of my function. Furthermore the simulation has to be such that it uses the above formula for the first entry but then replaces "Initial_Stock_Price" with the result of the preceding entry in each subsequent entry.
For some reason my array called "PriceSum" is not getting load with values or not being summed. I am not sure if it is because I am trying to load a value with a decimal in it or not.
Code: Private Sub Purchase_Click()Dim MyArray As Variant Dim x As Integer Dim t As Integer Dim lastrow As Integer Dim QuantityArray(0 To 1000) As Variant,
I have a big macro that runs whenever there is a change made. I'm not gonna link it all because I don't think that would be useful... This macro does:
1. Disables Events. 2. Removes Protection 3.Calls some macros that check a few values and change a few cells. 4. Activates events. 5. Hides or shows ranges of cells depending on the results of the called macros. 6. Reactivates protection.
As well as the cells the called macro changes, there is a column of True/False results stretching from AE16 to AE491 with several blanks in the list as well. (All of this is decided upon a different macro that isn't linked with the change.) I want a loop that will read the True/False column and if it finds a false, make 8 buttons invisible.
I tried putting this code between Step 5 and 6 of the macro.
Code: Dim J As Integer J = 16 Do
[Code].....
This isn't working at all... I was thinking if there was gonna be an issue then it would be the opposite where it stops the buttons appearing all together but even when there are falses and I am changing things it doesn't seem to make a difference.
I'm just getting into functions, so please bear with me on this as I start to understand how they really work. I do have the VBA and Macros for MS Excel book which has been a great help!
Normally on this I would use a simple array formula to gather a total calculation from a timesheet, but in this case there can be numerous timesheets to add this up.
Hours would be recorded on a sheet with both a client and a task selected. I also have a summary sheet to show clients against tasks... adding all the hours from each timesheet.
If it were from a single Timesheet (possibly creating a single one of these for all sheets is an option?) I would be able to use the following array formula:
=SUM(IF((Timesheet1!$F$8:$F$22=C$5)*(Timesheet1!$G$8:$G$22=$A9),Timesheet1!$D$8:$D$22)) Timesheet1 Column D = hours Timesheet1 Column F = clients Timesheet1 Column G = tasks Row 5 (starting Column C) = clients in summary sheet (across top) Column A (starting Row 9) = tasks in summary sheet (down side)...........
I am trying to write a public function that fills a table for a 2-dimensional array and am having trouble with my named ranges. The x-axis is based on years (range F2:O2) and the y-axis is a q_factor (range E3:E23) so the data range would be (F3:O23. The following outlines my logic:
Public Function bondValue(years As Range, q_factor As Range, z As Double)
Dim nRow As Long, nCol As Long Dim bondPort As Range
I have written the code below. But it didn't work. In my opinion the error is most probably caused by irr worksheet function. Because the code is actually bigger and I tried it all part by part.
Option Base 1 Dim i As Integer Dim j As Integer Dim counter As Integer Sub General() 'Makes general calculations Dim Cash_Flow_Project_Entity(49) As Variant 'Toplam Yatırım Nakit Akımı Dim FIRR(49) As Variant 'Yearly FIRR Analysis_Period = Worksheets("Veri"). Cells(15, 5) 'Takes " analysis period" from "Veri" Worksheet End Sub
I have the following assignment to do, problem is I'm new to arrays and functions in VBA and nothing is working for me, i get errors no matter what i try, (for example i don't know how to feed the array to the function, and it won't let me write a range to an array)
5.A) Write a function that takes a 2D array of doubles, a single cell range, an optional cap and an optional floor. B)Write the array on to the sheet with the single cell range parameter being the location of the top left of the array on the sheet. When writing the array to the sheet, for each value in the array where it is below the floor put the floor on the sheet, where the value is above the cap put the cap value on the sheet, otherwise display the original value. The input array should not be modified. All code should be what you consider production quality.
How can I obtain the array values from a function?
For example: Those steps were made by cytop to split a text (btw it works perfecet!!), I just added Function splitText(strSplit As Variant) As Variant ... End Function
VB: Function splitText(strSplit As Variant) As Variant Dim datosColumnaIncio() As Variant Dim iTemp As Integer Redim datosColumnaIncio(Len(strSplit) - 1) For iTemp = 1 To Len(strSplit) datosColumnaIncio(iTemp - 1) = Mid$(strSplit, iTemp, 1) Next End Function
So I want to know if its correct like that:
VB: Function splitText(strSplit As Variant) As Variant Dim datosColumnaIncio() As Variant Dim iTemp As Integer
[Code] .....
So when I call the function:
VB : MsgBox splitText("F4")
It throws an error message :s what is wrong or how can I get the array values of a function ???
