# Sparse Matrix Functions

```----------------------------------------------------------------
Elementary Sparse Matrices
----------------------------------------------------------------
spdiags     Sparse matrix formed from diagonals.
speye       Sparse identity matrix.
sprandn     Sparse random matrix.
sprandsym   Sparse symmetric random matrix.
----------------------------------------------------------------
```
```---------------------------------------------------------------------------
Full to Sparse Conversion
---------------------------------------------------------------------------
find        Find indices of nonzero entries.
full        Convert sparse matrix to full matrix.
sparse      Create sparse matrix from nonzeros and indices.
spconvert   Convert from sparse matrix external format.
---------------------------------------------------------------------------
```
```-------------------------------------------------------------------------------------------------
Working with Nonzero Entries of Sparse Matrices
-------------------------------------------------------------------------------------------------
issparse    True if matrix is sparse.
nnz         Number of nonzero entries.
nonzeros    Nonzero entries.
nzmax       Amount of storage allocated for nonzero entries.
spalloc     Allocate memory for nonzero entries.
spfun       Apply function to nonzero entries.
spones      Replace nonzero entries with ones.
-------------------------------------------------------------------------------------------------
```
```-------------------------------------------------------------
Visualizing Sparse Matrices
-------------------------------------------------------------
gplot       Plot graph, as in "graph theory."
spy         Visualize sparsity structure.
-------------------------------------------------------------
```
```------------------------------------------------------------
Reordering Algorithms
------------------------------------------------------------
colmmd      Column minimum degree.
colperm     Order columns based on nonzero count.
dmperm      Dulmage-Mendelsohn decomposition.
randperm    Random permutation vector.
symmmd      Symmetric minimum degree.
symrcm      Reverse Cuthill-McKee ordering.
------------------------------------------------------------
```
```------------------------------------------------------------
Norm, Condition Number, and Rank
------------------------------------------------------------
condest     Estimate 1-norm condition.
normest     Estimate 2-norm.
sprank      Structural rank.
------------------------------------------------------------
```
```---------------------------------------------------------
Miscellaneous
---------------------------------------------------------
spaugment   Form least squares augmented system.
spparms     Set parameters for sparse matrix routines.
symbfact    Symbolic factorization analysis.
---------------------------------------------------------
```

(c) Copyright 1994 by The MathWorks, Inc.