PLASMA
2.8.0
PLASMA - Parallel Linear Algebra for Scalable Multi-core Architectures
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int CORE_sgeqrt | ( | int | M, |
int | N, | ||
int | IB, | ||
float * | A, | ||
int | LDA, | ||
float * | T, | ||
int | LDT, | ||
float * | TAU, | ||
float * | WORK | ||
) |
CORE_sgeqrt computes a QR factorization of a complex M-by-N tile A: A = Q * R.
The tile Q is represented as a product of elementary reflectors
Q = H(1) H(2) . . . H(k), where k = min(M,N).
Each H(i) has the form
H(i) = I - tau * v * v'
where tau is a complex scalar, and v is a complex vector with v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in A(i+1:m,i), and tau in TAU(i).
[in] | M | The number of rows of the tile A. M >= 0. |
[in] | N | The number of columns of the tile A. N >= 0. |
[in] | IB | The inner-blocking size. IB >= 0. |
[in,out] | A | On entry, the M-by-N tile A. On exit, the elements on and above the diagonal of the array contain the min(M,N)-by-N upper trapezoidal tile R (R is upper triangular if M >= N); the elements below the diagonal, with the array TAU, represent the unitary tile Q as a product of elementary reflectors (see Further Details). |
[in] | LDA | The leading dimension of the array A. LDA >= max(1,M). |
[out] | T | The IB-by-N triangular factor T of the block reflector. T is upper triangular by block (economic storage); The rest of the array is not referenced. |
[in] | LDT | The leading dimension of the array T. LDT >= IB. |
[out] | TAU | The scalar factors of the elementary reflectors (see Further Details). |
[out] | WORK |
PLASMA_SUCCESS | successful exit |
<0 | if -i, the i-th argument had an illegal value |