I'm looking for a function that calculates the inverse of tan on delphi. I haven't been able to find a function in delphi that calculates the inverse of tan so any help is greatly appreciated.
You are looking for either: System.ArcTan or Math.ArcTan2.
You might find ArcTan2 to be more appropriate depending on your needs. The Wikipedia article on the subject might help you understand the difference between ArcTan2 and ArcTan.
Related
I am currently converting a project in F# to Python, I am a relative amateur in F#, please...what on earth does this line do...
let stats = new DescriptiveStatistics(list)
I cant find a good definition of DescriptiveStatistics anywhere! Please help!
Many thanks
That is very likely from MathNet.
Check the beginning of your F# for the line:
using MathNet.Numerics.Statistics;
https://numerics.mathdotnet.com/DescriptiveStatistics.html
"...in case you need to gather a whole set of statistical characteristics in one pass, is provided by the DescriptiveStatistics class:..." Thanks for your help guys
Can anyone please explain the logic behind the functions like "tsclean" & "nnetar" of the package "forecast" written by Professor Rob J Hyndman.
I can able to use the tsclean & nnetar.
I hope these are used for the outlier treatment in time series.
tsclean is used for outlier treatment, i.e. it removes outliers & it fills the missing values.
Request:
What is the method or logic behind it, please let me know (any reference material)
Thanks in Advance!!
I'm have to code my own implementation of FREAK descriptor for a homework. I actually read the original paper but there isn't any explanation of how the build the pattern used.
In the OpenCV code is defined the buildPattern() function but it also lack of documentation on how the pattern itself is build.
So my question is, does anybody knows how the pattern is defined and how the parameters (radius, sigmas and coordinates) are selected?
It looks like the exact values aren't important, but Figure 4 shows the rough layout of the 43 receptive fields.
Their exact geometry is defined by the code here: https://github.com/kikohs/freak/blob/master/src/freak.cpp#L212
new to F#
i need to store a bunch of lists of objects according to a float number where the collection of lists are sorted according to the float number. I know in C# i would use
SortedDictionary<float, List<obj>>
as the implementation is a red black tree, allowing for log(n) insert and search. But whats the best way to attack the situation in F#. I attempted to use SortedDitionary but i can't refer to SortedDictionary[int] to find the value so it renders it as useless essentially (i could be doing it wrong).
thanks for the help
The syntax is
sorteddictionary.[int]
then it works as you would expect
The first thig to do is read Okasaki's book Purely Functional Data Structures
It has ML implementations that may help you
You can use sorteddictionary.[int] as John Palmer already said but it may be worth pointing out that the F# standard library includes a purely functional sorted dictionary collection called Map.
Is it possible to create a link to just a hyperslab of a dataset in HDF5?
For example, I have one dataset of size 1000 x 3, representing (a,b,c) as a function of time, let's say. And now I want a link that points just to the 'a' data (1000 x 1). Is this possible?
[Having googled this extensively, I learned the valuable lesson that "link" is essentially useless in a google query. And I can't tell from the HDF5 documentation, so I'm sorry if this is stupid.]
Having asked at the (very helpful) HDF5 helpdesk, I find that the answer is no. For anyone else looking for this functionality: redesign your code/data structure.
Unfortunately for me, the code is not mine, and the data structure is set by other, stubborn people.