Category Archives: UDFs

Cubic splines with descending x

Posted on 01/03/2016 by dougaj4

In response to a recent comment, I have modified the CSpline2 spreadsheet so that the CSplineA and CHSplineA functions will accept x values list in descending order, as well as ascending.  For more details of the background to the functions, … Continue reading →

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Tanh-Sinh Quadrature via F2PY – Part 3

Posted on 06/02/2016 by dougaj4

For the last of the current series on combining Fortran, Python and Excel with F2PY and ExcelPython I have updated the xlSciPy spreadsheet to include two other variants of the Tanh-Sinh function: Quad_TSi integrates a non-periodic function over a semi-infinite … Continue reading →

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Tanh-Sinh Quadrature via F2PY – Part 2

Posted on 01/02/2016 by dougaj4

Lets look at some details of the coding. The original code (available here) includes routines “intdeini” to generate an array of points and weights of the quadrature formula, and “intde” to carry out the integration of any supplied function “f”. … Continue reading →

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Tanh-Sinh Quadrature via F2PY

Posted on 31/01/2016 by dougaj4

Fast and accurate numerical integration routines based on the Tanh-Sinh method are available as Excel VBA based functions in the Tanh_Sinh Quadrature spreadsheet by Graeme Dennes.  Graeme’s VBA code is based on open source Fortran code by Takuya Ooura, which … Continue reading →

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xlSciPy – Python SciPy for Excel; Update with new functions

Posted on 04/01/2016 by dougaj4

The xlSciPy spreadsheet, previously described here, has been updated with new functions for integration, finding equation roots and maxima and minima, solving systems of non-linear equations, and evaluation of equations entered as text.  The new version (including full open-source VBA … Continue reading →

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