MatSpy

Sparse matrix spy plot, HTML, and LaTeX rendering with Jupyter integration.

Purpose

Turn this:

<1005x1005 sparse array of type '<class 'numpy.float64'>'
	with 25571 stored elements in Compressed Sparse Row format>

To one of these:

Spy Plot	HTML	LaTeX
spy(A)	mdisplay(A)	mdisplay(A, 'latex')

from matspy import spy, mdisplay

Supports:

• scipy.sparse sparse matrices (both matrix and array variants)
• list, tuple (HTML and LaTeX only)

Spy plots

• spy(A): Plot the sparsity pattern (location of nonzero values) of sparse matrix A.
• to_sparkline(A): Return a small spy plot as an HTML string.
• spy_to_mpl(A): Same as spy() but returns the matplotlib Figure without showing it.
• to_spy_heatmap(A): Return the raw 2D array for spy plots.

Tabular

• to_html(A): Format A as an HTML table.
• to_latex(A): Format A as a LaTeX matrix.

These methods return a string. Use matspy.mdisplay() to display the HTML/LaTeX in Jupyter.

Jupyter Integration

MatSpy can integrate with Jupyter's formatter to format supported sparse matrix types. Importing the matspy.jupyter module performs this registration:

from matspy.jupyter import spy

If you prefer LaTeX:

from matspy.jupyter_latex import spy

To avoid registering anything, just import matspy:

from matspy import spy

Selected arguments

Accepted by all methods

• title: string label. If True, then a matrix description is auto generated.
• indices: Whether to show matrix indices.

HTML/Latex

• max_rows, max_rows: size of table. Matrices larger than this are truncated with ellipses.

Spy plots

• figsize, sparkline_size: size of the plot, in inches
• shading: binary, relative, absolute.
• dpi, buckets: pixel count of spy plot, relative to figure size or absolute, respectively.

Fast

All operations work with very large matrices. A spy plot of tens of millions of elements takes less than half a second. Tabular outputs are instant.

Large matrices are downscaled using two native matrix multiplies. The final dense 2D image is small.

Spy Plot Anti-Aliasing

One application of spy plots is to quickly see if a matrix has a noticeable structure. Aliasing artifacts can give the false impression of structure where none exists, such as moiré or even a false grid pattern.

MatSpy employs some simple methods to help eliminate these effects in most cases.

See the Anti-Aliasing demo for more.