Wolfram Function Repository

Instant-use add-on functions for the Wolfram Language

Function Repository Resource:

 ZeroDiagonal

Source Notebook

Replace the diagonal of an arbitrary matrix with zeros

Contributed by: Szabolcs Horvat

ResourceFunction["ZeroDiagonal"][matrix]

replaces the diagonal of matrix with zeros.

Details and Options

The input must be a full matrix. Higher-dimensional arrays cannot be used.
The matrix elements may be any expression, symbolic or numeric.
If the matrix contains machine-precision elements, the diagonal will be filled with machine-precision zeros. Otherwise, exact zeros will be used.

Examples

Basic Examples (1) 

Zero the diagonal of a matrix:

In[1]:=
ResourceFunction["ZeroDiagonal"][( { {1, 2, 3}, {4, 5, 6}, {7, 8, 9} } )]
Out[1]=

Scope (3) 

Use on a sparse matrix:

In[2]:=
sa = SparseArray[{{1, 1} -> 2, {1, 2} -> 3, {4, 5} -> 4}]
Out[2]=
In[3]:=
ResourceFunction["ZeroDiagonal"][sa]
Out[3]=

Use on a non-square matrix with symbols:

In[4]:=
ResourceFunction["ZeroDiagonal"][( { {a, 2, a^2}, {b, b^3, -1} } )] // MatrixForm
Out[4]=

Use on a machine-precision matrix:

In[5]:=
ResourceFunction["ZeroDiagonal"]@ RandomReal[{-1, 1}, {5, 5}] // MatrixForm
Out[5]=

Applications (1) 

Create a random directed graph with no self-loops:

In[6]:=
AdjacencyGraph@ ResourceFunction["ZeroDiagonal"]@RandomInteger[1, {5, 5}]
Out[6]=

Publisher

Szabolcs Horvat

Requirements

Wolfram Language 11.3 (March 2018) or above

Version History

  • 1.0.0 – 20 February 2019

License Information