norm
Compute the Norm of a Matrix

### Description

Displays the norm of a matrix according to the norm type.

### Usage

    norm(x, type, ...)

### Arguments

x | a numeric or a complex matrix.
type | a character string specified as the norm type. The norm type can be one of "O", "I", "1", "2", "F", or "M". See the Details section for their descriptions.

### Details

norm() uses the LAPACK routine "DLANGE" (numeric) or "ZLANGE" (complex) to calculate the norm of a matrix, except for type="2", which uses the svd function. The type argument defines the norm types:

- "O" or "1": The one norm of x (maximum column sum of abs(x)).
- "I": The infinity norm of x (maximum row sum abs(x)).
- "F": The Frobenius norm of x (square root of sum of squares of abs(x)).
- "M": The largest value in abs(x).
- "2": The largest singular value of x.

Note that a matrix norm is not the same as a vector norm.
Value
returns a numeric value representing the norm of a matrix.
Differences between Spotfire Enterprise Runtime for R and Open-source R
Open-source R does not handle complex matrices.
References
Anderson. E., et al. 1999. http://www.netlib.org/lapack/lug/lapack_lug.html. LAPACK Users' Guide. Third Edition. Philadelphia, PA: SIAM Publications.
Examples

    x <- cbind( -(1:4), (0:3), c(-3.5,-3.5,3.5,3.5))
    norm(x)
    norm(x, "M")
    norm(x, "O")
    norm(x, "I")
    norm(x, "F")
    norm(x, "2")

Package base version 6.1.5-18
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