custom function
 

Does anyone have any code (or at least enough to get me started) to perform
a linear interpolation of points? I want something with the following
inputs...

Point 1: 12
Value 1: 2.000
Point 2: 24
Value 2: 1.000
Desired Point: 15
Round: 3

Output would be 1.750

Formula would be as follows:
{(Value 1 - Value 2) x [(Point 2 - Desired Point)/(Point 2 - Point 1)]} +
Value 2

Thanks!!
Dave

custom function
 

Not sure you need code. Using a worksheet function:

=TREND({2,1},{12,24},15)

But you could use code:

Public Function Interpolate(Point1, Value1, Point2, Value2, Point3)
Interpolate = (Value1 - Value2) * _
((Point2 - Point3) / (Point2 - Point1)) + Value2
End Function


In article ,
"dave!!" wrote:

Does anyone have any code (or at least enough to get me started) to perform
a linear interpolation of points? I want something with the following
inputs...

Point 1: 12
Value 1: 2.000
Point 2: 24
Value 2: 1.000
Desired Point: 15
Round: 3

Output would be 1.750

Formula would be as follows:
{(Value 1 - Value 2) x [(Point 2 - Desired Point)/(Point 2 - Point 1)]} +
Value 2

Thanks!!
Dave

custom function
 

Thanks, I had just figured it out.

Another question though...

I need a function that will look at a range of values (sorted in ascending
order) and find the value just below some desired value.

For example, if I had a list of 1, 2, 3, 4, 5 and my value was 2.5, the
function would return 2.

Thanks
"JE McGimpsey" wrote in message
...
Not sure you need code. Using a worksheet function:

=TREND({2,1},{12,24},15)

But you could use code:

Public Function Interpolate(Point1, Value1, Point2, Value2, Point3)
Interpolate = (Value1 - Value2) * _
((Point2 - Point3) / (Point2 - Point1)) + Value2
End Function


In article ,
"dave!!" wrote:

Does anyone have any code (or at least enough to get me started) to
perform
a linear interpolation of points? I want something with the following
inputs...

Point 1: 12
Value 1: 2.000
Point 2: 24
Value 2: 1.000
Desired Point: 15
Round: 3

Output would be 1.750

Formula would be as follows:
{(Value 1 - Value 2) x [(Point 2 - Desired Point)/(Point 2 - Point 1)]}
+
Value 2

Thanks!!
Dave

custom function
 

Take a look at LOOKUP in XL Help.

In article ,
"dave!!" wrote:

I need a function that will look at a range of values (sorted in ascending
order) and find the value just below some desired value.

For example, if I had a list of 1, 2, 3, 4, 5 and my value was 2.5, the
function would return 2.

custom function
 

Dave,
How is the user going to input or select the values for Point 1
Point 2, Value 1, Value 2 and Desired Point?
Are these values already part of a worksheet or do you want them t
input the values into a userform?

In any case just assign appropriate variables to the correspondin
variable source then use the varialbes in a formula as you typed

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