linear-algebra

问题 I need to implement the Jacobi and Guass Seidel, methods in Matlab. I found this link which has code that produces correct results (on the one sample I tried) for each. See post 3. My problem is that the implementation is different to that described here, and here I'm happy enough using someone else's code (indeed I prefer something tried and tested) but I want to understand exactly how it works. Can someone point me to a description of the implementations used in the post? Alternately are

问题 I got a problem in understending the difference between MLP and SLP. I know that in the first case the MLP has more than one layer (the hidden layers) and that the neurons got a non linear activation function, like the logistic function (needed for the gradient descent). But I have read that: "if all neurons in an MLP had a linear activation function, the MLP could be replaced by a single layer of perceptrons, which can only solve linearly separable problems" I don't understand why in the

问题 I am new to world of matrix, sorry for this basic question I could not figure out: I have four matrix (one unknown). Matrix X x <- c(44.412, 0.238, -0.027, 93.128, 0.238, 0.427, -0.193, 0.673, 0.027, -0.193, 0.094, -0.428, 93.128, 0.673, -0.428, 224.099) X <- matrix(x, ncol = 4 ) Matrix B : need to be solved , 1 X 4 (column x nrows), with b1, b2, b3, b4 values Matrix G g <- c(33.575, 0.080, -0.006, 68.123, 0.080, 0.238, -0.033, 0.468, -0.006, -0.033, 0.084, -0.764, 68.123, 0.468, -0.764, 205

问题 I have these indexes: 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,etc... Which are indexes of nodes in a matrix (including diagonal elements): 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 etc... and I need to get i,j coordinates from these indexes: 1,1 2,1 2,2 3,1 3,2 3,3 4,1 4,2 4,3 4,4 5,1 5,2 5,3 5,4 5,5 6,1 6,2 6,3 6,4 6,5 6,6 etc... When I need to calculate coordinates I have only one index and cannot access others. 回答1: Not optimized at all : int j = idx; int i = 1; while(j > i) { j -=

问题 I'm looking to write some small library that use 2D and 3D points or directions in space (vector in vector/matrix sense, not Rust's Vec ). Rust doesn't impose rules here, so you can make a tuple of floats, or a new struct with x, y, z members. or a single data: [f64; 3] member. The reason I'd like to define a type here instead of using [f64; 3] , is so I can declare methods such as length , normalized , also Add , Sub operators. Whats a good basis to declare small 2D - 3D fixed sized data

问题 I'm doing some linear algebra math, and was looking for some really lightweight and simple to use matrix class that could handle different dimensions: 2x2, 2x1, 3x1 and 1x2 basically. I presume such class could be implemented with templates and using some specialization in some cases, for performance. Anybody know of any simple implementation available for use? I don't want "bloated" implementations, as I'll running this in an embedded environment where memory is constrained. Thanks 回答1: You

问题 I'm doing some linear algebra math, and was looking for some really lightweight and simple to use matrix class that could handle different dimensions: 2x2, 2x1, 3x1 and 1x2 basically. I presume such class could be implemented with templates and using some specialization in some cases, for performance. Anybody know of any simple implementation available for use? I don't want "bloated" implementations, as I'll running this in an embedded environment where memory is constrained. Thanks 回答1: You

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 5 months ago . I have a system of linear equations that make up an NxM matrix (i.e. Non-square) which I need to solve - or at least attempt to solve in order to show that there is no solution to the system. (more likely than not, there will be no solution) As I understand it, if my matrix is not square (over or under

问题 I am implementing the Gilbert-Johnson-Keerthi algorithm which computes whether two objects are intersecting (ie. colliding). The entry point to my code is the hasCollided function which takes two lists of points and returns True if they are intersecting. I believe I have implemented the paper correctly - however, I still have to implement the contains function. The contains function should determine whether a simplex contains the origin. I am unsure as to how to implement this. How do I

问题 does anybody know if there is a good gem for mathematic / geometric operations? I need some of this things: Dot product Cross product Angle between vectors Matrix Surface normale Vector calculations (add, substract...) Singular Value Decomposition thx, tux 回答1: I can highly recommend the Ruby/GSL gem. You may need to refer to the GSL manual to work out the name of the function you need to call though, if it's not documented in the Ruby/GSL documentation. 回答2: http://linalg.rubyforge.org/