.TH "BLAS/SRC/drotmg.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME BLAS/SRC/drotmg.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdrotmg\fP (dd1, dd2, dx1, dy1, dparam)" .br .RI "\fBDROTMG\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine drotmg (double precision dd1, double precision dd2, double precision dx1, double precision dy1, double precision, dimension(5) dparam)" .PP \fBDROTMG\fP .PP \fBPurpose:\fP .RS 4 .PP .nf CONSTRUCT THE MODIFIED GIVENS TRANSFORMATION MATRIX H WHICH ZEROS THE SECOND COMPONENT OF THE 2-VECTOR (DSQRT(DD1)*DX1,DSQRT(DD2)*> DY2)**T\&. WITH DPARAM(1)=DFLAG, H HAS ONE OF THE FOLLOWING FORMS\&.\&. DFLAG=-1\&.D0 DFLAG=0\&.D0 DFLAG=1\&.D0 DFLAG=-2\&.D0 (DH11 DH12) (1\&.D0 DH12) (DH11 1\&.D0) (1\&.D0 0\&.D0) H=( ) ( ) ( ) ( ) (DH21 DH22), (DH21 1\&.D0), (-1\&.D0 DH22), (0\&.D0 1\&.D0)\&. LOCATIONS 2-4 OF DPARAM CONTAIN DH11, DH21, DH12, AND DH22 RESPECTIVELY\&. (VALUES OF 1\&.D0, -1\&.D0, OR 0\&.D0 IMPLIED BY THE VALUE OF DPARAM(1) ARE NOT STORED IN DPARAM\&.) THE VALUES OF GAMSQ AND RGAMSQ SET IN THE DATA STATEMENT MAY BE INEXACT\&. THIS IS OK AS THEY ARE ONLY USED FOR TESTING THE SIZE OF DD1 AND DD2\&. ALL ACTUAL SCALING OF DATA IS DONE USING GAM\&. .fi .PP .RE .PP \fBParameters\fP .RS 4 \fIDD1\fP .PP .nf DD1 is DOUBLE PRECISION .fi .PP .br \fIDD2\fP .PP .nf DD2 is DOUBLE PRECISION .fi .PP .br \fIDX1\fP .PP .nf DX1 is DOUBLE PRECISION .fi .PP .br \fIDY1\fP .PP .nf DY1 is DOUBLE PRECISION .fi .PP .br \fIDPARAM\fP .PP .nf DPARAM is DOUBLE PRECISION array, dimension (5) DPARAM(1)=DFLAG DPARAM(2)=DH11 DPARAM(3)=DH21 DPARAM(4)=DH12 DPARAM(5)=DH22 .fi .PP .RE .PP \fBAuthor\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP .PP Definition at line \fB89\fP of file \fBdrotmg\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.