larfy - larfy: apply Householder reflector symmetrically (2-sided)

Generated automatically by Doxygen for LAPACK from the source code. Version 3.12.0 Sun Jul 20 2025 01:40:05 larfy(3)

subroutineclarfy(characteruplo,integern,complex,dimension(*)v,integerincv,complextau,complex,dimension(ldc,*)c,integerldc,complex,dimension(*)work)CLARFYPurpose: CLARFY applies an elementary reflector, or Householder matrix, H, to an n x n Hermitian matrix C, from both the left and the right. H is represented in the form H = I - tau * v * v' where tau is a scalar and v is a vector. If tau is zero, then H is taken to be the unit matrix. ParametersUPLO UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the Hermitian matrix C is stored. = 'U': Upper triangle = 'L': Lower triangle N N is INTEGER The number of rows and columns of the matrix C. N >= 0. V V is COMPLEX array, dimension (1 + (N-1)*abs(INCV)) The vector v as described above. INCV INCV is INTEGER The increment between successive elements of v. INCV must not be zero. TAU TAU is COMPLEX The value tau as described above. C C is COMPLEX array, dimension (LDC, N) On entry, the matrix C. On exit, C is overwritten by H * C * H'. LDC LDC is INTEGER The leading dimension of the array C. LDC >= max( 1, N ). WORK WORK is COMPLEX array, dimension (N) Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. subroutinedlarfy(characteruplo,integern,doubleprecision,dimension(*)v,integerincv,doubleprecisiontau,doubleprecision,dimension(ldc,*)c,integerldc,doubleprecision,dimension(*)work)DLARFYPurpose: DLARFY applies an elementary reflector, or Householder matrix, H, to an n x n symmetric matrix C, from both the left and the right. H is represented in the form H = I - tau * v * v' where tau is a scalar and v is a vector. If tau is zero, then H is taken to be the unit matrix. ParametersUPLO UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix C is stored. = 'U': Upper triangle = 'L': Lower triangle N N is INTEGER The number of rows and columns of the matrix C. N >= 0. V V is DOUBLE PRECISION array, dimension (1 + (N-1)*abs(INCV)) The vector v as described above. INCV INCV is INTEGER The increment between successive elements of v. INCV must not be zero. TAU TAU is DOUBLE PRECISION The value tau as described above. C C is DOUBLE PRECISION array, dimension (LDC, N) On entry, the matrix C. On exit, C is overwritten by H * C * H'. LDC LDC is INTEGER The leading dimension of the array C. LDC >= max( 1, N ). WORK WORK is DOUBLE PRECISION array, dimension (N) Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. subroutineslarfy(characteruplo,integern,real,dimension(*)v,integerincv,realtau,real,dimension(ldc,*)c,integerldc,real,dimension(*)work)SLARFYPurpose: SLARFY applies an elementary reflector, or Householder matrix, H, to an n x n symmetric matrix C, from both the left and the right. H is represented in the form H = I - tau * v * v' where tau is a scalar and v is a vector. If tau is zero, then H is taken to be the unit matrix. ParametersUPLO UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the symmetric matrix C is stored. = 'U': Upper triangle = 'L': Lower triangle N N is INTEGER The number of rows and columns of the matrix C. N >= 0. V V is REAL array, dimension (1 + (N-1)*abs(INCV)) The vector v as described above. INCV INCV is INTEGER The increment between successive elements of v. INCV must not be zero. TAU TAU is REAL The value tau as described above. C C is REAL array, dimension (LDC, N) On entry, the matrix C. On exit, C is overwritten by H * C * H'. LDC LDC is INTEGER The leading dimension of the array C. LDC >= max( 1, N ). WORK WORK is REAL array, dimension (N) Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. subroutinezlarfy(characteruplo,integern,complex*16,dimension(*)v,integerincv,complex*16tau,complex*16,dimension(ldc,*)c,integerldc,complex*16,dimension(*)work)ZLARFYPurpose: ZLARFY applies an elementary reflector, or Householder matrix, H, to an n x n Hermitian matrix C, from both the left and the right. H is represented in the form H = I - tau * v * v' where tau is a scalar and v is a vector. If tau is zero, then H is taken to be the unit matrix. ParametersUPLO UPLO is CHARACTER*1 Specifies whether the upper or lower triangular part of the Hermitian matrix C is stored. = 'U': Upper triangle = 'L': Lower triangle N N is INTEGER The number of rows and columns of the matrix C. N >= 0. V V is COMPLEX*16 array, dimension (1 + (N-1)*abs(INCV)) The vector v as described above. INCV INCV is INTEGER The increment between successive elements of v. INCV must not be zero. TAU TAU is COMPLEX*16 The value tau as described above. C C is COMPLEX*16 array, dimension (LDC, N) On entry, the matrix C. On exit, C is overwritten by H * C * H'. LDC LDC is INTEGER The leading dimension of the array C. LDC >= max( 1, N ). WORK WORK is COMPLEX*16 array, dimension (N) Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd.

larfy - larfy: apply Householder reflector symmetrically (2-sided)

Functions subroutine clarfy (uplo, n, v, incv, tau, c, ldc, work) CLARFY subroutine dlarfy (uplo, n, v, incv, tau, c, ldc, work) DLARFY subroutine slarfy (uplo, n, v, incv, tau, c, ldc, work) SLARFY subroutine zlarfy (uplo, n, v, incv, tau, c, ldc, work) ZLARFY