# rcond

## Purpose

Matrix condition number estimate.

## Synopsis

    c = rcond(X)

## Description

`rcond(X)` is an estimate for the reciprocal of the condition of `X` in 1-norm using the LINPACK condition estimator. If `X` is well conditioned, `rcond(X)` is near 1.0. If `X` is badly conditioned, `rcond(X)` is near 0.0. Compared to `cond`, `rcond` is a more efficient, but less reliable, method of estimating the condition of a matrix.

## Algorithm

`rcond` uses the condition estimator from the LINPACK routine `ZGECO`.

## See Also

    cond, condest, norm, normest, rank, svd

## References

[1] J.J. Dongarra, J.R. Bunch, C.B. Moler, and G.W. Stewart, LINPACK
User's Guide, SIAM, Philadelphia, 1979.

(c) Copyright 1994 by The MathWorks, Inc.