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# Questions tagged [sparse-arrays]

Questions on the construction and manipulation of sparse arrays in Mathematica, with functions like SparseArray[] and Band[].

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### Find a few eigenvalues of a HUGE sparse Hermitian matrix

I know that methods such as Arnoldi and FEAST can be employed to only find a few eigenvalues. But now I need to add another ...
186 views

### Fast way to reassemble SparseArrays

I often have to deal with nonlinear shape optimization problems involving curves or surfaces surfaces. A classical example is Plateau's problem. No matter if I use gradient-based techniques (such as ...
140 views

### Reorder matrix for nested dissection

I'm implementing a nested dissection linear solver outside of Mathematica and my original data is actually a graph, from which I have to construct an appropriate adjacency matrix to feed into the ...
34 views

### Odd behavior of ArrayReshape with SparseArrays

I am trying to understand why I am seeing inconsistent results when using ArrayReshape on a SparseArray vs. a normal nested <...
289 views

38 views

### 3D Sparse array [duplicate]

Following the 3D matrix representation shown here Vitaliy Kaurov's answer for "Plot 3D boolean Array or matrix in Mathematica" Is it possible to use a SparseArray ...
264 views

### Generating a (sparse?) array from data

I have a list: {{pos_1,val_1},{pos_2,val_2},...} and would like to generate an array of dimension d, with values ...
41 views

### NetTrain doesn't accept sparse input?

The following code fails to execute: ...
321 views

### Most efficient way to build block / banded SparseArray

I have a matrix that I generate with a procedure that looks like this: ...
96 views

### efficient replacing of certain diagonal parts of array/matrix

in writing some code for FEM i need an efficient way to replace parts of the diagonal of a sparse array. Certain positions in the diagonal of the array (given in a list) should be changed to "1". An ...