Description of getrs

getrs		Programmers Guide
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Category:mtl2lapack

Component type:function

Prototype

template <class LapackMatrixA, class LapackMatrixB, class VectorInt> int getrs(char transa, LapackMatrixA& a, VectorInt& ipivot, LapackMatrixB& b) ;

Description

Solves a system of linear equations A*X = B with a general NxN matrix A using the LU factorization computed by GETRF.

transa (IN - char) 'T' for the transpose of A, 'N' otherwise.
a (IN - matrix(M,N)) The factors L and U from the factorization A = P*L*U as computed by GETRF.
ipivot (IN - vector(min(M,N))) Integer vector. The pivot indices from GETRF; row i of A was interchanged with row IPIV(i).
b (IN/OUT - matrix(ldb,NRHS)) Matrix of same numerical type as A. On entry, the right hand side matrix B. On exit, the solution matrix X.
info (OUT - int) 0 : function completed normally < 0 : The ith argument, where i = abs(return value) had an illegal value. > 0 : if INFO = i, U(i,i) is exactly zero; the matrix is singular and its inverse could not be computed.

Definition

mtl2lapack.h

Preconditions

Complexity

Example

Notes

See also