# All Questions

45 questions
Filter by
Sorted by
Tagged with
45 views

### How to grab two points from linear equations and from a matrix m.x == b for the purpose of creating lines or planes from each row.?

Don't get me wrong I can easily do it on paper and I could probably write convoluted code that will get the job done but I feel like there has to be an easy Mathematica way to do this. A few users on ...
119 views

### Determinant of 11x11 Matrix consumes immense amount of memory

I'm trying to take the determinant of an 11x11 matrix, constructed out of some functions I've defined ...
49 views

### Help in modifying my code

In my code, I want to plot (Dis[t]). The problem is some functions containing in the code do not work well if there are variables in the form of symbols, such as "Sort" "NMaximize" functions. I want ...
67 views

### Find minimum with matrix positive-definiteness constraint

Say I wish to find the minimum value of the determinant of a symmetric matrix under the condition that the matrix be positive definite. So I attempt: ...
75 views

### Maximize a six-dimensional function subject to joint positive-semidefiniteness constraints

I want to maximize Abs[a1 b1] + Abs[a2 b2] + Abs[a3 b3] subject to the joint constraints ...
412 views

### How to use genetic algorithm to calculate the maximum value of this matrix

1-9 the 9 numbers are arranged into 3 * 3 matrix without repetition.How to select the matrix with the largest determinant value: ...
87 views

### Proving the positive semidefiniteness of a 6X6 symbolic matrix

Specifically, I want to check the positive semidefiniteness of the following 6X6 symbolic matrix ...
130 views

### Minimizing expression over symmetric matrices

I'm trying to solve the following maximization problem over space of symmetric matrices A and positive definite H $$R=\max_{A\in S(R^d)}\frac{\text{tr}(HA)^2+2\text{tr}(HAHA)}{\text{tr}(AHA)}$$ So ...
212 views

154 views

### How to improve the speed of NMaximize function

My problem is as follows: Consider a 5*5 matrix Obj with 0 and 1 Obj = Array[x, {5, 5}]; The objective function is: ...
128 views

### How to efficiently optimize a strictly increasing linear function over convex set

I am trying to minimize the trace of a symmetric matrix $B$ fulfilling $x^T A_i x \leq x^T B x \ \forall x \forall i$ for given (in general) indefinite symmetric matrices $A_i, i = 1, ..., n$. The ...
56 views

### Minimize matrix column totals

I would like to pick up n (2 in example) columns from matrix. The sum/total of these columns should be minimal. ...
960 views

### Differentiating functions of vectors/matrices?

I'm dealing with derivatives of scalar functions of matrices and wondering if Mathematica can help me here. The standard approach of expanding it in terms of components is cumbersome. As an ...
52 views

### Specific aggregation of matrix elements

Let us consider the matrix 'x1': x1 = {{1, 2, 3, m}, {4, 5, 6, n}, {7, 8, 9, o}, {10, 11, 12, o}} MatrixForm[x1] From the matrix 'x1' we compute the matrix 'x2':...
647 views

### How can I fit a matrix function with multiple variables to given eigenvalues?

I have a 5x5 matrix function H[kx] ...
66 views

### Finding a column from Max comparing each element of two columns; subsequent column used for backward calculation

I have lensp=21; rho=0.975; e1=0; pid= 0.5212; qid=0.4788; tid=10; based on my own calculations I have given vectors of dimension ...
261 views

### Defining a function for the construction of a bordered hessian

I think in Mathematica the omission of a function that can create a bordered matrix. This code works ...
95 views

### An optimization problem involving the calculation of MatrixRank as a constraint

I am dealing with an optimization problem that involves the rank of a matrix as a hard constraint. I am starting with this simple example ...
68 views

### An optimization problem involving the calculation of MatrixRank gets wrong

I was trying to solve an optimization problem involving rank of a matrix and experimenting with a very simple one. A 2x2 matrix which contains only one parameter a11...
414 views

### Need an efficient method for finding certain matrices

I am trying to write a function which produces square matrices with certain characteristics. The function should have two inputs: number of the rows, n number of ...
368 views

### Optimize a parametric matrix to get a lowest possible eigenvalue

This question is a followup of Plot the lowest eigenvalues of a parametric matrix Now I can get the lowest eigenvalue LowEign(t) of the matrix for a given t numerically. When I plot the LowEign ...
625 views

### Find the minimum element of a row of a matrix and its column index for each row

I am trying to find the minimum value of a row of a matrix and its corresponding column. Please run the code below. OptV is the matrix that I would like to create which must give the output of the ...
824 views