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gives the nn identity matrix.
  • The option WorkingPrecision can be used to specify the precision of matrix elements.
Construct a 3×3 identity matrix:
Construct a 3×3 identity matrix:
Click for copyable input
Construct a 3×4 identity matrix:
Create a machine-precision identity matrix:
Use DiagonalMatrix for general diagonal matrices:
The KroneckerProduct of a matrix with the identity matrix is a block diagonal matrix:
The WorkingPrecision option is equivalent to creating the matrix, then applying N:
IdentityMatrix gives a matrix with dense storage. SparseArray is more compact:
The SparseArray representation uses a fraction of the memory:
For matrix and arithmetic operations they are effectively equal:
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