Questions on the manipulation of matrices in Mathematica.

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Applied Linear Algebra | Prove the intersection of two subspaces [migrated]

Question: Determine whether or not any column in the matrix is a linear combination of other columns. Provide a general method for answering the same question for any n x n matrix A. My response: ...
28
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2answers
689 views

eigenvector bug?

Bug introduced in 7.0.1 or earlier and fixed in 10.0.0 I have a fairly simple $3\times3$ complex matrix, $$ M=\left( \begin{array}{ccc} \frac{7}{2}-\frac{i}{2} & -1+i & \frac{1}{2}+\frac{5 ...
7
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1answer
234 views

Is it possible to implement symbolic sub matrices?

The accepted answer in the following link: http://stackoverflow.com/questions/5708208/symbolic-matrices-in-mathematica-with-unknown-dimensions provides a functionality to create symbolic matrices ...
2
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1answer
69 views

Abstract iterator in Do

I'm trying to write a module. Its input is a matrix (tensor), the module should return new tensor with increased rank with 1. The new tensor is defined as $$ O \Rightarrow N_{\alpha \beta \ldots ...
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1answer
53 views

Finite Field matrix rank calculation

How does one define a matrix over $GF(p^r)$ in mathematica in order to compute rank? I am working with $GF(2)$?
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2answers
68 views

Problem in matrix multiplication

I created a random directed acyclic graph using Mathematica. I need to compute a specific function from its adjacency matrix. ...
3
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3answers
74 views

Express block matrix in terms of matrix basis

I'm trying to construct a function that returns the multiplication table of a matrix Lie algebra. Assuming a basis of matrices, my definitions: ...
2
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2answers
157 views

Are there any good mass row/column swapping functions for matrices?

I have the following matrix Keeping the 20 row and 20 column fixed (so the 21st rows and columns because I started at 0)...how do I push each row and column back one spot? I need to push the 0th row ...
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3answers
197 views

Writing code to update a large matrix?

How can I write a code to update a matrix based on certain rules? I plan on constructing a large matrix, and I cannot submit entries one by one. The rules for the matrix are as followed: $$ ...
1
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1answer
95 views

How to add an extra column to a current matrix (list)? [duplicate]

a = {{-800, 1712}, {-801, 1713}, {-806, 1832}} TableForm[a] b = a[[All, 2]] - Min[a[[All, 2]]] How do I make a new matrix (list) whic looks like this ...
2
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1answer
95 views

How do I generate all $n\times m$ matrices s.t. $a_{i,j} \in {a … b}$?

Is there a fast and clean way of generating all possible $n\times m$ matrices s.t. $a_{i,j} \in \{a ... b\}$ - much like Range does in $N$? Consider for example that for $n,m = 2$, $a=0$, $b=2$ I ...
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0answers
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How can I get symbolic orthonormal eigenvectors for 3 by 3 hermitian matrix?

Using the following syntax, I can obtain the symbolic eigenvalues and eigenvectors of the following Hermitian matrix (a,b,c,d are all real parameters): ...
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0answers
31 views

How to change dimensions of a matrix?

I have two sets of data that I'm working with, both of which should be 1024 x 1024 matrices (they're from the same instrument). However, when I go to manipulate them, the dimensions of one are read as ...
4
votes
4answers
596 views

Writing a circular matrix

I have two square matrices, $A$ and $B$, of the same size, say, of $m \times m$. What I want is to write a programme/function of three variables, $A$, $B$ and $n$, that outputs the $mn \times mn$ ...
-2
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1answer
71 views

Recreating in Mathematica a matrix created in Python [closed]

I need to recreate in Mathematica this matrix that I created in Python: ...
0
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0answers
44 views

Getting problems while calculating nxn matrix: output does not make sense [closed]

With this code I should be able to calculate the Wab, which is supposed to be a nxn matrix. The problem is that this matrix ...
0
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1answer
55 views

Plotting six chosen rows of a matrix

I have a matrix,W, whose dimension is n x n, each entry is a number. I need to plot only the values of six rows, namely those ...
0
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1answer
68 views
1
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2answers
90 views

Filing matrix by bands [closed]

I need to fill a matrix, CSI, by taking elements from an array, inverse, which is the Inverse Fast Fourier Transform of an array ...
2
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1answer
54 views

sparse array with list [closed]

i'm trying to populate a sparse array with lists in certain positions, i tried the following code, ...
0
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0answers
28 views

Translation matrix in sperical coordinates system [migrated]

I'm using WorldWind software to draw segments (polyline) on the globe to materialize an aircraft flightplan. Each point in a flightplan is named waypoint. Waypoints are expressed in geographical ...
1
vote
2answers
48 views

How can I manipulate this list?

I performed a loop with Table where I solve a system of 4 equations that depends on two parameters: eta and p. I create two lists for each parameter as follows: ...
1
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1answer
68 views

Defining a function of matrices [closed]

I am translating my code from Python to Mathematica. How can I define a function similar to the following: ...
0
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3answers
76 views

Define a matrix depending on variable in Mathematica [closed]

I am translating my code from Python to Mathematica. I am trying to define a matrix, whose values depend on a variable chosen by the user, called kappa. In Python the code looked like that: ...
1
vote
4answers
97 views

calculating subsets of a matrix (L=40X40)

I need to calculate all $k$-possible subsets$(k:1,L)$ of matrix with size $L$. I am using subset function as following, ...
0
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1answer
48 views

What is the “proper” way of multiplying a list of vectors by a matrix? Why Map does not work? [closed]

I am an absolute newbie with Mathematica, so please forgive me if this is stupid, but for the life of me I can't solve this. Suppose I have a list of vectors $b_{1...n}$ and a square matrix $A$ and I ...
14
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5answers
3k views

Best way to create symmetric matrices

From time to time I need to generate symmetric matrices with relatively expensive cost of element evaluation. Most frequently these are Gram matrices where elements are $L_2$ dot products. Here are ...
27
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4answers
3k views

Why does MatrixForm affect calculations?

This is a really newbie question, but it has me confused. Why does this code work without // MatrixForm and doesn't work with ...
78
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7answers
21k views

Elegant operations on matrix rows and columns

Question The Mathematica tutorial has a section 'Basic Matrix Operations', describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...
0
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1answer
47 views

Assigning some results after a solve procedure to the coefficients of a matrix

I have a matrix M[3,3]. After a solve procedure, I obtained these results. {{M[1, 2] -> Cos[ψ[t]], M[1, 3] -> 0, M[2, 3] -> 0, Cos[θ[t]] -> M[3, 1], M[3, 2] -> 0, M[3, 3] -> 1, M[2, 1] -> ...
2
votes
3answers
129 views

Unragging a matrix

Today I ran into matrices like this one: ...
2
votes
3answers
123 views

How to insert a Matrix into a larger matrix

I have a 4x4 matrix v1 v2 v3 v4 myM={{a1,a2,c1,c2}, v1 {a2,a3,c2,c3}, v2 {c1,c2,d1,d2}, v3 {c2,c3,d2,d3}} v4 And I want to ...
0
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0answers
30 views

How to add a positive definiteness of a unsymmetric matrix as a constraint to a Findminimum problem

The problem is I have a function which has 33 variables, and which to minimize it in a given set of contraints. I have also a matrix consisting of these 33 variables. The condition is that this matrix ...
0
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0answers
9 views

Add positive definite matrix constraint to an optimization problem [duplicate]

The problem is I have a function which has 33 variables, and which to minimize it in a given set of contraints. I have also a matrix consisting of these 33 variables. The condition is that this matrix ...
8
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0answers
121 views

Bug in PositiveDefiniteMatrixQ?

Fixed in 10.1.0. Exists in at least 9.0.1 -- 10.0.2. This seems like a bug in PositiveDefiniteMatrixQ to me: ...
0
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1answer
42 views

Maximum element and its position (row,column) of matrix

Can someone help me to get the maximum element of $m\times n$ matrix and corresponding row and column $(i,j)$?
1
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1answer
58 views

Counting and updating a subset of matrix

I have an n by n matrix and would like to count the number of sub-matrices that is equal to a given matrix. Here is my code: DWBCL creates a matrix with elements a1, a2 and c2 in it and DWBCH with b1, ...
1
vote
2answers
52 views

Filling a matrix with a list of lists

I have a list of lists with different lengthes: {{a1,a2},{b1,b2},{c1,c2,c3},...} Now I want to create a matrix the following way: ...
0
votes
1answer
49 views

Elements inside arrays seem to be strings rather than signed numbers

When I have code like b = Array[Subscript[be, #] &, {3, 1}] b = b /. {Subscript[be, k_] :> Subscript[-be, k] /; k > 1} I am noticing that Mathematica ...
3
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3answers
140 views

Creating a matrix under conditions

I would like to create a matrix whose elements satisfy the following conditions ( Mathematica 9 ) ...
1
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1answer
63 views

Optimizing matrix inequalities over trace

I need to solve the following problem. Given $n \times n$ Hermitian matrices $A\geq 0$ and $B_1, ~ B_2$ (need not be positive semidefinite), with $Tr(AB_1)<0~,Tr(AB_2)<0$ construct a ...
2
votes
1answer
103 views

Proving positive definiteness or semi-definiteness of a matrix

I have the following 4x4 real symmetric matrix: $K=\begin{bmatrix}3-3w & -\frac{4}{3}+a+2w & \frac{5}{12}+b-\frac{w}{2} & 0\\ -\frac{4}{3}+a+2w & -1-6a-3x & ...
1
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1answer
81 views

Getting a part of a matrix Inverse for later use

I was trying to get an element of a matrix, and use in further computation of my program. Problem was that its not reading the value unless and until I specify it again. My code is: ...
0
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2answers
38 views

in the part assignment is not a symbol, create different matrices with a loop

Im trying to assemble new matrices from some previous matrices I have created, but I can´t. What Im trying to do is the following: 1) I have different matrices: ...
0
votes
1answer
72 views

How to obtain a convergent solution iteratively for a linear system of equations

I am working on a problem that requires an iterative procedure to solve a linear system of equations, the system of equations in matrix form is: $$\underbrace{\begin{bmatrix} r_{11} & r_{12} ...
2
votes
1answer
149 views

Is there a bug in MatrixExp in Mathematica v10?

I'm trying to compute MatrixExp[-I t {{0, 1/2, 0, 0, 1/2}, {1/2, 0, 1/2, 0, 0}, {0, 1/2, 0, 1/2, 0}, {0, 0, 1/2, 0, 1/2}, {1/2, 0, 0, 1/2, 0}}] With ver 9 the ...
0
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2answers
70 views

Block anti-diagonalize a square matrix?

In Mathematica there is a very convenient function called JordanDecomposition[]. It takes a square matrix A as an argument and ...