lapack_int LAPACKE_slarfg( lapack_int n, float* alpha, float* x,
lapack_int incx, float* tau )
{
#ifndef LAPACK_DISABLE_NAN_CHECK
/* Optionally check input matrices for NaNs */
if( LAPACKE_s_nancheck( 1, alpha, 1 ) ) {
return -2;
}
if( LAPACKE_s_nancheck( 1+(n-2)*ABS(incx), x, incx ) ) {
return -3;
}
#endif
return LAPACKE_slarfg_work( n, alpha, x, incx, tau );
}
int
CORE_shbrce(int uplo, int N,
PLASMA_desc *A,
float *V,
float *TAU,
int st,
int ed,
int eltsize)
{
int NB, J1, J2, J3, KDM2, len, pt;
int len1, len2, t1ed, t2st;
int i;
static float zzero = 0.0;
PLASMA_desc vA=*A;
/* Check input arguments */
if (N < 0) {
coreblas_error(2, "Illegal value of N");
return -2;
}
if (ed <= st) {
coreblas_error(6, "Illegal value of st and ed (internal)");
return -6;
}
/* Quick return */
if (N == 0)
return PLASMA_SUCCESS;
NB = A->mb;
KDM2 = A->mb-2;
if( uplo == PlasmaLower ) {
/* ========================
* LOWER CASE
* ========================*/
for (i = ed; i >= st+1 ; i--){
/* apply Householder from the right. and create newnnz outside the band if J3 < N */
J1 = ed+1;
J2 = min((i+1+KDM2), N);
J3 = min((J2+1), N);
len = J3-J1+1;
if(J3>J2)*A(J3,(i-1))=zzero;/* could be removed because A is supposed to be band.*/
t1ed = (J3/NB)*NB;
t2st = max(t1ed+1,J1);
len1 = t1ed-J1+1; /* can be negative*/
len2 = J3-t2st+1;
if(len1>0)CORE_slarfx2(PlasmaRight, len1, *V(i), *TAU(i), A(J1, i-1), ELTLDD(vA, J1), A(J1 , i), ELTLDD(vA, J1) );
if(len2>0)CORE_slarfx2(PlasmaRight, len2, *V(i), *TAU(i), A(t2st,i-1), ELTLDD(vA, t2st), A(t2st, i), ELTLDD(vA, t2st));
/* if nonzero element a(j+kd,j-1) has been created outside the band (if index < N) then eliminate it.*/
len = J3-J2; // soit 1 soit 0
if(len>0){
/* generate Householder to annihilate a(j+kd,j-1) within the band */
*V(J3) = *A(J3,i-1);
*A(J3,i-1) = 0.0;
LAPACKE_slarfg_work( 2, A(J2,i-1), V(J3), 1, TAU(J3));
}
}
/* APPLY LEFT ON THE REMAINING ELEMENT OF KERNEL 2 */
for (i = ed; i >= st+1 ; i--){
/* find if there was a nnz created. if yes apply left else nothing to be done.*/
J2 = min((i+1+KDM2), N);
J3 = min((J2+1), N);
len = J3-J2;
if(len>0){
pt = J2;
J1 = i;
J2 = min(ed,N);
t1ed = (J2/NB)*NB;
t2st = max(t1ed+1,J1);
len1 = t1ed-J1+1; /* can be negative*/
len2 = J2-t2st+1;
if(len1>0)CORE_slarfx2(PlasmaLeft, len1 , *V(J3), (*TAU(J3)), A(pt, i ), ELTLDD(vA, pt), A((pt+1), i ), ELTLDD(vA, pt+1) );
if(len2>0)CORE_slarfx2(PlasmaLeft, len2 , *V(J3), (*TAU(J3)), A(pt, t2st), ELTLDD(vA, pt), A((pt+1), t2st), ELTLDD(vA, pt+1) );
}
}
} else {
/* ========================
* UPPER CASE
* ========================*/
for (i = ed; i >= st+1 ; i--){
/* apply Householder from the right. and create newnnz outside the band if J3 < N */
J1 = ed+1;
J2 = min((i+1+KDM2), N);
J3 = min((J2+1), N);
len = J3-J1+1;
if(J3>J2)*A((i-1), J3)=zzero;/* could be removed because A is supposed to be band.*/
t1ed = (J3/NB)*NB;
t2st = max(t1ed+1,J1);
len1 = t1ed-J1+1; /* can be negative*/
len2 = J3-t2st+1;
if(len1>0)CORE_slarfx2(PlasmaLeft, len1 , (*V(i)), *TAU(i), A(i-1, J1 ), ELTLDD(vA, (i-1)), A(i, J1 ), ELTLDD(vA, i) );
if(len2>0)CORE_slarfx2(PlasmaLeft, len2 , (*V(i)), *TAU(i), A(i-1, t2st), ELTLDD(vA, (i-1)), A(i, t2st), ELTLDD(vA, i) );
/* if nonzero element a(j+kd,j-1) has been created outside the band (if index < N) then eliminate it.*/
len = J3-J2; /* either 1 soit 0*/
if(len>0){
/* generate Householder to annihilate a(j+kd,j-1) within the band*/
*V(J3) = *A((i-1), J3);
*A((i-1), J3) = 0.0;
LAPACKE_slarfg_work( 2, A((i-1), J2), V(J3), 1, TAU(J3));
}
}
/* APPLY RIGHT ON THE REMAINING ELEMENT OF KERNEL 2*/
for (i = ed; i >= st+1 ; i--){
/* find if there was a nnz created. if yes apply right else nothing to be done.*/
J2 = min((i+1+KDM2), N);
J3 = min((J2+1), N);
len = J3-J2;
if(len>0){
pt = J2;
J1 = i;
J2 = min(ed,N);
t1ed = (J2/NB)*NB;
t2st = max(t1ed+1,J1);
len1 = t1ed-J1+1; /* can be negative*/
len2 = J2-t2st+1;
if(len1>0)CORE_slarfx2(PlasmaRight, len1 , (*V(J3)), (*TAU(J3)), A(i , pt), ELTLDD(vA, i), A(i, pt+1), ELTLDD(vA, i) );
if(len2>0)CORE_slarfx2(PlasmaRight, len2 , (*V(J3)), (*TAU(J3)), A(t2st, pt), ELTLDD(vA, t2st), A(t2st, pt+1), ELTLDD(vA, t2st) );
}
}
} /* end of else for the upper case */
return PLASMA_SUCCESS;
}
