# LinearAlgebraOperationsExtensions.SymmetricMatrixNorm<T>(ILinearAlgebraOperations<T>, MatrixNorm, MatrixTriangle, Int32, ReadOnlySpan2D<T>) Method

Returns the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real symmetric matrix A.

## Definition

**Namespace:**Extreme.Collections

**Assembly:**Extreme.Numerics (in Extreme.Numerics.dll) Version: 9.0.0

```
public static T SymmetricMatrixNorm<T>(
this ILinearAlgebraOperations<T> operations,
MatrixNorm norm,
MatrixTriangle storedTriangle,
int n,
ReadOnlySpan2D<T> a
)
```

#### Parameters

- operations ILinearAlgebraOperations<T>
- norm MatrixNorm
Specifies the value to be returned in DLANSY as described above.

- storedTriangle MatrixTriangle
Specifies whether the upper or lower triangular part of the symmetric matrix A is to be referenced. = 'U': Upper triangular part of A is referenced = 'L': Lower triangular part of A is referenced

- n Int32
The order of the matrix A. N >= 0. When N = 0, DLANSY is set to zero.

- a ReadOnlySpan2D<T>
Dimension (LDA,N) The symmetric matrix A. If UPLO = 'U', the leading n by n upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = 'L', the leading n by n lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced.

The leading dimension of the array A. LDA >= max(N,1).

#### Type Parameters

- T

#### Return Value

T#### Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type ILinearAlgebraOperations<T>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).## Remarks

DLANSY = ( max(abs(A(i,j))), NORM = 'M' or 'm' ( ( norm1(A), NORM = '1', 'O' or 'o' ( ( normI(A), NORM = 'I' or 'i' ( ( normF(A), NORM = 'F', 'f', 'E' or 'e' ere norm1 denotes the one norm of a matrix (maximum column sum), ormI denotes the infinity norm of a matrix (maximum row sum) and normF denotes the Frobenius norm of a matrix (square root of sum of squares). Note that max(abs(A(i,j))) is not a consistent matrix norm.

This method corresponds to the LAPACK routine DLANSY.