This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English version of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materials including this page, select Japan from the country navigator on the bottom of this page.


2-norm estimate


nrm = normest(S)
nrm = normest(S,tol)
[nrm,count] = normest(...)


This function is intended primarily for sparse matrices, although it works correctly and may be useful for large, full matrices as well.

nrm = normest(S) returns an estimate of the 2-norm of the matrix S.

nrm = normest(S,tol) uses relative error tol instead of the default tolerance 1.e-6. The value of tol determines when the estimate is considered acceptable.

[nrm,count] = normest(...) returns an estimate of the 2-norm and also gives the number of power iterations used.


The power iteration involves repeated multiplication by the matrix S and its transpose, S'. The iteration is carried out until two successive estimates agree to within the specified relative tolerance.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

See Also

| | | |

Introduced before R2006a

Was this topic helpful?