covariance_开发者

log covariance to arithmetic covariance matrix function?

Is there a function that can convert a covariance matrix built using log-returns into a covariance matrix based on simple arithmetic returns?[详细]

2023-04-11 12:43 分类：问答

Why Animals[] animals = new Cat[5] compiles, but List<Animal> animals = new List<Cat>() does not?

In his book C# in Depth, Jon Skeet tries to answer the following question: Why can\'tI convert List<string> to List<object>?[详细]

2023-04-08 05:00 分类：问答

Implementing explicit interface members with generics

I have a nongeneric interface to a generic class group. I have a method which uses covariance to return a strongly typed instance in a class derived from an abstract implementation of the non-generic[详细]

2023-04-08 04:06 分类：问答

Compute covariance matrix using Excel

In Excel, I have 10 columns of data from column A to column J, and each column has 1000 rows from row 1 to row 1000. I wonder how to compute the 10 x 10 covariance matrix of th开发者_Python百科e 10 co[详细]

2023-04-08 02:51 分类：问答

How to fix this error? Invalid variance: The type parameter 'T' must be invariantly valid on

I\'m having the below error message at compile time: \"Invalid variance: The type parameter \'T\' must be invariantly valid on \'ConsoleApplication1.IRepository.GetAll()\'. \'T\' is covariant.\"[详细]

2023-04-05 07:27 分类：问答

Array covariance in F#

Since .NET arrays are covariant, the following works in C#: var strArray = new string[0]; object[] objArray = strAr开发者_如何学运维ray;[详细]

2023-04-03 02:39 分类：问答

C++ Covariance and references

Lets say I have an abstract base class with a pure virtual that returns an 开发者_JAVA技巧expensive object.As it\'s an expensive object, I should return a reference to it.[详细]

2023-03-31 21:42 分类：问答

What's the performance hit of List.OfType<> where the entire list is that type?

I have an architecture where we are passing our data nodes as IE开发者_如何转开发numerable<BaseNode>. It all works great, but in each subclass we want to store these as List<AnotherNode> a[详细]

2023-03-30 15:28 分类：问答

Override contra-variance workaround needed

I\'m having difficulty finding the (what I\'m sure is a very common) design pattern to work around the following problem. Consider this piece of code:[详细]

2023-03-29 14:07 分类：问答