All Questions
Tagged with numerical-value matrix
15 questions
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A problem with obtaining the beam frequencies and mode shapes
I am supposed to find the mode shapes of two assembled beams. To this end, we must reduce the PDE equation of motion of beam to an ODE including the oscillation frequency. The solution of ODE has some ...
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0
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51
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Nested NIntegrate with Matrix Exponential
I wish to perform a numerical integration which involves a matrix exponential. Here's the following code
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- 385
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2
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200
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Why does NDSolveValues give different results?
I'm trying to solve this differential equation to obtain the density matrix elements $\rho_{22}$.
$$\frac{d\rho}{dt}=-i\Big(H_{0}(t)\rho(t)-\rho(t)H^{\dagger}_{0}(t)\Big)$$,
for non-Hermitian ...
- 51
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1
answer
169
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Why do different calculations give different eigenvalues?
I find the eigenvalues of the Hamiltonian in two ways - numerically and matrix . Why do different calculations give different eigenvalues?
The Hamiltonian is H = -1/2*Laplacian -(2/r)
It can be seen ...
- 1,913
2
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2
answers
103
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Optimising eigenvalue matrix calculation
I'm quite new to mathematica and am trying to figure out how to optimise my code as currently it takes a very long time to compile and makes it hard to bug test. The first part that creates the graph ...
- 175
-1
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1
answer
259
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How to split data in a matrix
Consider the matrix 'm1' :
m1 = RandomReal[{0, 1}, {50, 50}];
MatrixForm@m1
The partition of this matrix into non-overlapping rectangles (arranged horizontally)
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- 1,029
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130
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Can't create matrix function of symbolic functions and assign values to elements
So I have a problem regarding the symbolic matrix value assignment.
Say I create a matrix function as:
P[t_]:= {{P1[t]}, {P2[t]}, {P3[t]}};
Then I want to assign ...
2
votes
1
answer
60
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Phenomena between ill-conditioned and well-condtioned
Given that I have the following sparse matrix:
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- 119
3
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1
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260
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Proving the positive semidefiniteness of a 6X6 symbolic matrix
Specifically, I want to check the positive semidefiniteness of the following 6X6 symbolic matrix
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3
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53
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Low precision from function returning matrix
Got a function depending on single parameter "t" defined below which
returns a 2 by 2 matrix
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- 345
0
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0
answers
167
views
1
vote
1
answer
83
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Optimising matrix calculation [closed]
I was calculating the elements of a matrix like this:
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- 1,121
4
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1
answer
129
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Why does this test yield True
I have this test implemented in my code, when I import a numeric matrix, which I thought would be bulletproof, but it's failing in this case:
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- 1,211
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2
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158
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I'm trying to solve a system of complex equations
I'm simply trying to solve a system of equations and mathematica can't do it for all values over the region of interest. I have a 3x3 matrix that has a specific parametrization and after squaring the ...
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1
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99
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Difference Eigenvector values in mathematica 9 and mathematica 10 [duplicate]
I have the following matrix;
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- 157