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by Cuchulainn
July 20th, 2019, 4:48 pm
Forum: Programming and Software Forum
Topic: Python tricks
Replies: 135
Views: 15589

Re: Python tricks

C# experts: what's the best online tutorial for C#? I know Java, C++ and Python.
C# in a Nutshell by Albahari brothers is great. I reckon you can learn the language essentials in a few weeks. C# is closer to C++11 than it is to Java.

And C++/CLI speaks both C# and native C++.
by Cuchulainn
July 19th, 2019, 6:01 pm
Forum: Politics Forum
Topic: Are you ready for Brexit?
Replies: 519
Views: 10877

Re: Are you ready for Brexit?

I didn't know you cared.
by Cuchulainn
July 19th, 2019, 4:41 pm
Forum: Numerical Methods Forum
Topic: Smoothing splines (clamped spline)
Replies: 14
Views: 397

Re: Smoothing splines (clamped spline)

Well, as your are looking for [$]N[$] locally cubic spline, each spline is defined by [$]4[$] parameters. (e.g [$]4 N[$] unknowns). The cubics need to match at the knots points ([$] 2 N[$] equations). Make also the first derivative & second derivatives continuous at the interior knots points ([$] N...
by Cuchulainn
July 19th, 2019, 4:39 pm
Forum: Numerical Methods Forum
Topic: Smoothing splines (clamped spline)
Replies: 14
Views: 397

Re: Smoothing splines (clamped spline)

Well, as your are looking for [$]N[$] locally cubic spline, each spline is defined by [$]4[$] parameters. (e.g [$]4 N[$] unknowns). The cubics need to match at the knots points ([$] 2 N[$] equations). Make also the first derivative & second derivatives continuous at the interior knots points ([$] N...
by Cuchulainn
July 19th, 2019, 3:34 pm
Forum: Politics Forum
Topic: Are you ready for Brexit?
Replies: 519
Views: 10877

Re: Are you ready for Brexit?

I see the French foreign minister was in our village today. Now that's solidarity!!
A fine dividing line. And it makes you so unhappy.
25 years ago you have a 18-year old Scots para pointing a weapon at your windscreen.

Image
by Cuchulainn
July 19th, 2019, 3:00 pm
Forum: Numerical Methods Forum
Topic: Smoothing splines (clamped spline)
Replies: 14
Views: 397

Re: Smoothing splines (clamped spline)

My feeling is that I understand the requirement * + A + B + C. The solver compute the coefficients of the cubic spline. Natural BCs are not very difficult. So put Farid's 4N unknowns in a (some) NL solver, yes? I don't think it is all that difficult but you probably need to do preprocessing of the i...
by Cuchulainn
July 18th, 2019, 1:19 pm
Forum: Numerical Methods Forum
Topic: Smoothing splines (clamped spline)
Replies: 14
Views: 397

Re: Smoothing splines (clamped spline)

Here is Python code (MM can also do it for sure). The bigger the smooth the better the fit. import numpy as np import matplotlib.pyplot as plt import csaps np.random.seed(1234) x = np.linspace(-5., 5., 25) y = np.exp(-(x/2.5)**2) + (np.random.rand(25) - 0.2) * 0.3 sp = csaps.UnivariateCubicSmoothing...
by Cuchulainn
July 18th, 2019, 10:28 am
Forum: Off Topic
Topic: Grammar Time!
Replies: 1614
Views: 184688

Re: Grammar Time!

I meant another type of gizmoid, but you were close (gizmoids are a class of mathematical functions which are particularly useful).
Four candles?

www.youtube.com/watch?v=Wi1jjYLugs8
by Cuchulainn
July 18th, 2019, 10:23 am
Forum: Numerical Methods Forum
Topic: Smoothing splines (clamped spline)
Replies: 14
Views: 397

Re: Smoothing splines (clamped spline)

That's clear, Alan. Thanks So, you want SSSP + (A) together? In that case I reckon that the algorithm can be modified as an optimisation problem. But instead of solving a tridiagonal matrix system we must minimise a nonlinear function for the coefficients of the cubic spline. Looks benign enough esp...
by Cuchulainn
July 18th, 2019, 10:13 am
Forum: Numerical Methods Forum
Topic: High Accuracy Greeks computation under trinomial model
Replies: 4
Views: 159

Re: High Accuracy Greeks computation under trinomial model

I doubt (very much) if the Trinomial method and divided differences will bring any joy. I don't want to delineate all the issues that must be addressed. In short, I think it is not very good. Certainly not under all parameter regimes. Do people use this method in real life?  A better approach is to ...
by Cuchulainn
July 17th, 2019, 10:03 pm
Forum: Off Topic
Topic: Grammar Time!
Replies: 1614
Views: 184688

Re: Grammar Time!

logical digression

??
Maybe you thinking of 

[$]1/(1 + e^{-x})[$]

Folklore, Writing and a Sense of Place":

??
by Cuchulainn
July 17th, 2019, 9:32 pm
Forum: Numerical Methods Forum
Topic: Smoothing splines (clamped spline)
Replies: 14
Views: 397

Re: Smoothing splines (clamped spline)

Alan.  My 2018 C++ book has a chapter on this + code. I remember a number of boundary conditons. I don't have the book here. 1200 pages is a bit too much across the sea :-) BTW what do you mean by 'smoothing', precisely? enum CubicSplineBC {SecondDeriv, FirstDeriv}; I have just sent you the code The...
by Cuchulainn
July 17th, 2019, 5:36 pm
Forum: Politics Forum
Topic: Are you ready for Brexit?
Replies: 519
Views: 10877

Re: Are you ready for Brexit?

A spiffing tale of how Brexit was ‘spaffed’ away  https://www.irishtimes.com/opinion/fintan-o-toole-a-spiffing-tale-of-how-brexit-was-spaffed-away-1.3950422 under  David Davis , described by  Chris Patten  in a foreword to Cook’s book as “breezy, open, amiable, lazy and incompetent”. Mandarins who ...
by Cuchulainn
July 17th, 2019, 3:19 pm
Forum: Off Topic
Topic: Stupid question of the day
Replies: 2030
Views: 90286

Re: Stupid question of the day

What’s the strangest thing you’ve found left in a hotel room? It’ll probably be similar to things left on the London Underground: wooden legs, sex aids, unfinished novels. Unfinished sandwiches. Unfinished novels about unfinished sandwiches. I’ve just found a pair of false eyelashes in the bathroom...
by Cuchulainn
July 17th, 2019, 2:48 pm
Forum: Off Topic
Topic: Stupid question of the day
Replies: 2030
Views: 90286

Re: Stupid question of the day

You have moonshine confused with methanol. The head may contain a small amount of it (methanol, that is), but using modern equipment this does not constitute much of a danger. The big danger is smoke and razzias. www.youtube.com/watch?v=AV4UivC-f6M Do you have your own stil in the basement? Or a pr...
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