p?org2l/p?ung2l
p?org2l/p?ung2l
Generates all or part of the orthogonal/unitary matrix Q from a QL factorization determined by
p?geqlf
(unblocked algorithm).Syntax
void
psorg2l
(
MKL_INT
*m
,
MKL_INT
*n
,
MKL_INT
*k
,
float
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
float
*tau
,
float
*work
,
MKL_INT
*lwork
,
MKL_INT
*info
);
void
pdorg2l
(
MKL_INT
*m
,
MKL_INT
*n
,
MKL_INT
*k
,
double
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
double
*tau
,
double
*work
,
MKL_INT
*lwork
,
MKL_INT
*info
);
void
pcung2l
(
MKL_INT
*m
,
MKL_INT
*n
,
MKL_INT
*k
,
MKL_Complex8
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_Complex8
*tau
,
MKL_Complex8
*work
,
MKL_INT
*lwork
,
MKL_INT
*info
);
void
pzung2l
(
MKL_INT
*m
,
MKL_INT
*n
,
MKL_INT
*k
,
MKL_Complex16
*a
,
MKL_INT
*ia
,
MKL_INT
*ja
,
MKL_INT
*desca
,
MKL_Complex16
*tau
,
MKL_Complex16
*work
,
MKL_INT
*lwork
,
MKL_INT
*info
);
Include Files
- mkl_scalapack.h
Description
The
p?org2l/p?ung2l
function
generates an m
-by-n
real/complex distributed matrix Q
denoting A
(
with orthonormal columns, which is defined as the last ia
:ia
+m
-1, ja
:ja
+n
-1)n
columns of a product of k
elementary reflectors of order m
: Input Parameters
- m
- (global)The number of rows in the distributed submatrixQ..m≥0
- n
- (global)The number of columns in the distributed submatrixQ..m≥n≥0
- k
- (global)The number of elementary reflectors whose product defines the matrixQ..n≥k≥0
- a
- Pointer into the local memory to an array of size.lld_a*LOCc(ja+n-1)On entry, thej-th columnof the matrix stored inmust contain the vector that defines the elementary reflectoraH(, as returned byj),ja+n-k≤j≤ja+n-kp?geqlfin thekcolumns of its distributed matrix argumentA(.ia:*,ja+n-k:ja+n-1)
- ia
- (global)The row index in the global matrixAindicating the first row of sub(A).
- ja
- (global)The column index in the global matrixAindicating the first column of sub(A).
- desca
- (global and local) array of sizedlen_. The array descriptor for the distributed matrixA.
- tau
- (local)Array of size.LOCc(ja+n-1)contains the scalar factor of the elementary reflectortau[j]H, as returned by(j+1),j= 0, 1, ...,-1LOCc(ja+n-1)p?geqlf.
- work
- (local)Workspace array of sizelwork.
- lwork
- (local or global)The size of the arraywork.lworkis local input and must be at least, wherelwork≥mpa0 + max(1,nqa0)iroffa=mod(ia-1,mb_a),,icoffa= mod(ja-1,nb_a),iarow=indxg2p(ia,mb_a,myrow,rsrc_a,nprow),iacol=indxg2p(ja,nb_a,mycol,csrc_a,npcol),mpa0 =numroc(m+iroffa,mb_a,myrow,iarow,nprow).nqa0 =numroc(n+icoffa,nb_a,mycol,iacol,npcol)indxg2pandnumrocare ScaLAPACK tool functions;myrow,mycol,nprow, andnpcolcan be determined by calling thefunctionblacs_gridinfo.If, thenlwork= -1lworkis global input and a workspace query is assumed; thefunctiononly calculates the minimum and optimal size for all work arrays. Each of these values is returned in the first entry of the corresponding work array, and no error message is issued bypxerbla.
Output Parameters
- a
- On exit, this array contains the local pieces of them-by-ndistributed matrixQ.
- work
- On exit,returns the minimal and optimalwork[0]lwork.
- info
- (local).= 0: successful exit< 0: if thei-th argument is an array and thej-th entry, indexedhad an illegal value,j-1,theninfo= - (i*100 +j),if thei-th argument is a scalar and had an illegal value,theninfo= -i.