# dlaic1.f(3) [centos man page]

dlaic1.f(3) LAPACK dlaic1.f(3)NAME

dlaic1.f-SYNOPSIS

Functions/Subroutines subroutine dlaic1 (JOB, J, X, SEST, W, GAMMA, SESTPR, S, C) DLAIC1 applies one step of incremental condition estimation.Function/Subroutine Documentation subroutine dlaic1 (integerJOB, integerJ, double precision, dimension( j )X, double precisionSEST, double precision, dimension( j )W, double precisionGAMMA, double precisionSESTPR, double precisionS, double precisionC) DLAIC1 applies one step of incremental condition estimation. Purpose: DLAIC1 applies one step of incremental condition estimation in its simplest version: Let x, twonorm(x) = 1, be an approximate singular vector of an j-by-j lower triangular matrix L, such that twonorm(L*x) = sest Then DLAIC1 computes sestpr, s, c such that the vector [ s*x ] xhat = [ c ] is an approximate singular vector of [ L 0 ] Lhat = [ w**T gamma ] in the sense that twonorm(Lhat*xhat) = sestpr. Depending on JOB, an estimate for the largest or smallest singular value is computed. Note that [s c]**T and sestpr**2 is an eigenpair of the system diag(sest*sest, 0) + [alpha gamma] * [ alpha ] [ gamma ] where alpha = x**T*w. Parameters: JOB JOB is INTEGER = 1: an estimate for the largest singular value is computed. = 2: an estimate for the smallest singular value is computed. J J is INTEGER Length of X and W X X is DOUBLE PRECISION array, dimension (J) The j-vector x. SEST SEST is DOUBLE PRECISION Estimated singular value of j by j matrix L W W is DOUBLE PRECISION array, dimension (J) The j-vector w. GAMMA GAMMA is DOUBLE PRECISION The diagonal element gamma. SESTPR SESTPR is DOUBLE PRECISION Estimated singular value of (j+1) by (j+1) matrix Lhat. S S is DOUBLE PRECISION Sine needed in forming xhat. C C is DOUBLE PRECISION Cosine needed in forming xhat. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Definition at line 135 of file dlaic1.f.AuthorGenerated automatically by Doxygen for LAPACK from the source code.Version 3.4.2Tue Sep 25 2012 dlaic1.f(3)

## Check Out this Related Man Page

zlaic1.f(3) LAPACK zlaic1.f(3)NAME

zlaic1.f-SYNOPSIS

Functions/Subroutines subroutine zlaic1 (JOB, J, X, SEST, W, GAMMA, SESTPR, S, C) ZLAIC1 applies one step of incremental condition estimation.Function/Subroutine Documentation subroutine zlaic1 (integerJOB, integerJ, complex*16, dimension( j )X, double precisionSEST, complex*16, dimension( j )W, complex*16GAMMA, double precisionSESTPR, complex*16S, complex*16C) ZLAIC1 applies one step of incremental condition estimation. Purpose: ZLAIC1 applies one step of incremental condition estimation in its simplest version: Let x, twonorm(x) = 1, be an approximate singular vector of an j-by-j lower triangular matrix L, such that twonorm(L*x) = sest Then ZLAIC1 computes sestpr, s, c such that the vector [ s*x ] xhat = [ c ] is an approximate singular vector of [ L 0 ] Lhat = [ w**H gamma ] in the sense that twonorm(Lhat*xhat) = sestpr. Depending on JOB, an estimate for the largest or smallest singular value is computed. Note that [s c]**H and sestpr**2 is an eigenpair of the system diag(sest*sest, 0) + [alpha gamma] * [ conjg(alpha) ] [ conjg(gamma) ] where alpha = x**H * w. Parameters: JOB JOB is INTEGER = 1: an estimate for the largest singular value is computed. = 2: an estimate for the smallest singular value is computed. J J is INTEGER Length of X and W X X is COMPLEX*16 array, dimension (J) The j-vector x. SEST SEST is DOUBLE PRECISION Estimated singular value of j by j matrix L W W is COMPLEX*16 array, dimension (J) The j-vector w. GAMMA GAMMA is COMPLEX*16 The diagonal element gamma. SESTPR SESTPR is DOUBLE PRECISION Estimated singular value of (j+1) by (j+1) matrix Lhat. S S is COMPLEX*16 Sine needed in forming xhat. C C is COMPLEX*16 Cosine needed in forming xhat. Author: Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. Date: September 2012 Definition at line 136 of file zlaic1.f.AuthorGenerated automatically by Doxygen for LAPACK from the source code.Version 3.4.2Tue Sep 25 2012 zlaic1.f(3)