Visible to Intel only — GUID: GUID-803E18B4-6D63-4C6A-8F0D-91F6CA8C342B
Visible to Intel only — GUID: GUID-803E18B4-6D63-4C6A-8F0D-91F6CA8C342B
?orgtr
Generates the real orthogonal matrix Q determined by ?sytrd.
lapack_int LAPACKE_sorgtr (int matrix_layout, char uplo, lapack_int n, float* a, lapack_int lda, const float* tau);
lapack_int LAPACKE_dorgtr (int matrix_layout, char uplo, lapack_int n, double* a, lapack_int lda, const double* tau);
- mkl.h
The routine explicitly generates the n-by-n orthogonal matrix Q formed by ?sytrd when reducing a real symmetric matrix A to tridiagonal form: A = Q*T*QT. Use this routine after a call to ?sytrd.
- matrix_layout
-
Specifies whether matrix storage layout is row major (LAPACK_ROW_MAJOR) or column major (LAPACK_COL_MAJOR).
- uplo
-
Must be 'U' or 'L'.
Use the same uplo as supplied to ?sytrd.
- n
-
The order of the matrix Q (n≥ 0).
- a, tau
-
Arrays:
a (size max(1, lda*n)) is the array a as returned by ?sytrd.
tau is the array tau as returned by ?sytrd.
The size of tau must be at least max(1, n-1).
- lda
-
The leading dimension of a; at least max(1, n).
- a
-
Overwritten by the orthogonal matrix Q.
This function returns a value info.
If info=0, the execution is successful.
If info = -i, the i-th parameter had an illegal value.
The computed matrix Q differs from an exactly orthogonal matrix by a matrix E such that ||E||2 = O(ε), where ε is the machine precision.
The approximate number of floating-point operations is (4/3)n3.
The complex counterpart of this routine is ungtr.