### Install NDimensionalSparseArrays.jl

Source: https://github.com/juliasparse/ndimensionalsparsearrays.jl/blob/main/README.md

Installs the NDimensionalSparseArrays.jl package using the Julia package manager.

```julia
pkg> add NDimensionalSparseArrays
```

--------------------------------

### Create NDSparseArray instances

Source: https://github.com/juliasparse/ndimensionalsparsearrays.jl/blob/main/README.md

Demonstrates various methods to create NDSparseArray objects, including empty arrays, from dense arrays, and using specialized constructors like spzeros and spones.

```julia
using NDimensionalSparseArrays

# Create an empty 3x4x2 sparse array of Float64
A = NDSparseArray{Float64}(3, 4, 2)

# Create from a dense array (only non-zero elements are stored)
dense_array = [1 0 3; 0 0 0; 2 0 0]
B = NDSparseArray(dense_array)

# Create a sparse array of zeros
C = spzeros(Int, 5, 5)

# Create a sparse array of ones
D = spones(2, 2)
```

--------------------------------

### NDSparseArray Sparsity Handling

Source: https://github.com/juliasparse/ndimensionalsparsearrays.jl/blob/main/README.md

Illustrates functions for inspecting and managing the sparsity of NDSparseArray objects, including counting non-zero elements, calculating sparsity, accessing stored data, and memory compression.

```julia
# Get the number of non-zero elements
nnz(B)

# Get the sparsity of the array (fraction of zero elements)
sparsity(B)

# Get the stored indices and values
indices = stored_indices(B)
values = stored_values(B)
pairs = stored_pairs(B)

# Find the indices and values of non-zero elements
(I, V) = findnz(B)

# Remove stored zeros to save memory
compress!(B)
```

--------------------------------

### NDSparseArray Arithmetic Operations

Source: https://github.com/juliasparse/ndimensionalsparsearrays.jl/blob/main/README.md

Demonstrates basic arithmetic operations such as addition, subtraction, and scalar multiplication performed on NDSparseArray objects.

```julia
A = NDSparseArray([1 0; 0 4])
B = NDSparseArray([0 2; 3 0])

# Addition
C = A + B  # [1 2; 3 4]

# Subtraction
D = A - B  # [1 -2; -3 4]

# Scalar multiplication
E = A * 2  # [2 0; 0 8]
```

--------------------------------

### Access and Modify NDSparseArray Elements

Source: https://github.com/juliasparse/ndimensionalsparsearrays.jl/blob/main/README.md

Shows how to set, retrieve, and check for the existence of elements within an NDSparseArray, including using a default value for unset indices.

```julia
A = NDSparseArray{Float64}(3, 3)

# Set values
A[1, 1] = 10.0
A[3, 2] = -5.0

# Get values
value = A[1, 1]  # returns 10.0

# Check if an index has a stored value
hasindex(A, 1, 1)  # true
hasindex(A, 1, 2)  # false

# To get a value with a default for unset indices
get(A, (1, 2), 0.0) # returns 0.0
```

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