101 SUBROUTINE zlapll( N, X, INCX, Y, INCY, SSMIN )
109 INTEGER INCX, INCY, N
110 DOUBLE PRECISION SSMIN
113 COMPLEX*16 X( * ), Y( * )
119 DOUBLE PRECISION ZERO
120 parameter ( zero = 0.0d+0 )
122 parameter ( cone = ( 1.0d+0, 0.0d+0 ) )
125 DOUBLE PRECISION SSMAX
126 COMPLEX*16 A11, A12, A22, C, TAU
129 INTRINSIC abs, dconjg
149 CALL zlarfg( n, x( 1 ), x( 1+incx ), incx, tau )
153 c = -dconjg( tau )*zdotc( n, x, incx, y, incy )
154 CALL zaxpy( n, c, x, incx, y, incy )
156 CALL zlarfg( n-1, y( 1+incy ), y( 1+2*incy ), incy, tau )
163 CALL dlas2( abs( a11 ), abs( a12 ), abs( a22 ), ssmin, ssmax )
subroutine dlas2(F, G, H, SSMIN, SSMAX)
DLAS2 computes singular values of a 2-by-2 triangular matrix.
subroutine zlapll(N, X, INCX, Y, INCY, SSMIN)
ZLAPLL measures the linear dependence of two vectors.
subroutine zlarfg(N, ALPHA, X, INCX, TAU)
ZLARFG generates an elementary reflector (Householder matrix).
subroutine zaxpy(N, ZA, ZX, INCX, ZY, INCY)
ZAXPY