OpenXlFun (XlXtrFun Replacement)

I have been using the XlXtrFun.xll add-in for many years now and it has become integral to many of my engineering spreadsheets. http://www.xlxtrfun.com/XlXtrFun/XlXtrFun.htm

The concern is that being a compiled add-in it is fast becoming incompatible with the newer versions of Excel. In short, most of the functions work up to Excel 2010 (I know that the PfitData does not). However, it seems that the addin will not load with 2013. Hence the reason for this thread.

The objective would be to compile a OpenXlFun.xlam that overtime can grow to incorporate replacement functions so that those of us who have integrated XlXtrFun into their spreadsheets can continue to use these functions into the future.

There are a number of threads that address these functions else where in this forum. This would simply provide a single collaborative space. Let me know what you think.

A list of the functions, numbered for thread reference:

1D Numerical Functions

1.1 LookupClosestValue

Returns the element in an array which is closest to a given value

1.2 IndexOfClosestValue

Returns the 1-based index of the element in an array which is closest to a given value

2D Numerical Functions

2.1 LookupClosestValue2D

Returns the element in a 2-D array which is closest to two given values

2.2 Pfit

Returns the Y which lies on the polynomial line fit by the least squares method

2.3 PfitData

Returns the coefficients and statistics for the polynomial line fit by the least squares method

2.4 Spline

Returns the Y which lies on the cubic (or natural) spline curve at the given X

2.5 Interpolate

Returns the Y which lies on an interpolated curve at the given X

2.5a Interp

Returns the Y which lies on an interpolated curve at the given X using the defaults of Interpolate

2.6 XatY

Returns the X value at the Max. (Peak),. Min (Valley), or Given Y of an interpolated curve

2.7 Intersect

Returns the X value at the intersection of two lines defined by arrays of points

2.8 ddydx

Returns the second derivative of the interpolated curve at the given X using the defaults of Interpolate

2.9 dydx

Returns the first derivative of the interpolated curve at the given X using the defaults of Interpolate

3D Numerical Functions

3.1 Interp3D

Returns an interpolated Z for known X's, known Y's, known Z's, and a given X and Y using the defaults of Interpolate

3.2 InterpMatrix

Given an X, Y, Z matrix like an efficiency hill curve matrix, interpolates or extrapolates a Z using the defaults of Interpolate