SRC/DEPRECATED/dlatzm.f(3)

okay bestie, buckle up: this is the manual page for SRC/DEPRECATED/dlatzm.f(3) from the Library Functions Manual 💅✨

💖 NAME

SRC/DEPRECATED/dlatzm.f — yes, that’s the whole name, and she’s serving deprecated-but-documented realness 🎀

🌸 SYNOPSIS

🧚 Functions/Subroutines

• subroutine dlatzm (side, m, n, v, incv, tau, c1, c2, ldc, work) — DLATZM 🦋

🦋 Function/Subroutine Documentation

   subroutine dlatzm (character side, integer m, integer n, double precision,
       dimension( * ) v, integer incv, double precision tau, double precision,
       dimension( ldc, * ) c1, double precision, dimension( ldc, * ) c2,
       integer ldc, double precision, dimension( * ) work)

✨ DLATZM

okay so this is the subroutine in question, and the manpage literally just says DLATZM here. icon behavior 💅

💖 Purpose

⚠️ Deprecated alert, bestie: This routine is deprecated and has been replaced by routine DORMRZ. no cap, she said what she said 😭

DLATZM applies a Householder matrix generated by DTZRQF to a matrix.

Let

P = I - tau*u*u**T,   u = ( 1 ),
                              ( v )

where v is an (m-1) vector if SIDE = 'L', or a (n-1) vector if SIDE = 'R'.

If SIDE equals 'L', let

       C = [ C1 ] 1
           [ C2 ] m-1
             n

Then C is overwritten by P*C.

If SIDE equals 'R', let

       C = [ C1, C2 ] m
              1  n-1

Then C is overwritten by C*P.

🎀 Parameters

• SIDE — SIDE is CHARACTER*1
  • = 'L': form P * C
  • = 'R': form C * P
• M — M is INTEGER
  • The number of rows of the matrix C.
• N — N is INTEGER
  • The number of columns of the matrix C.
• V — V is DOUBLE PRECISION array, dimension
  • (1 + (M-1)*abs(INCV)) if SIDE = 'L'
  • (1 + (N-1)*abs(INCV)) if SIDE = 'R'

The vector v in the representation of P. V is not used if TAU = 0.

• INCV — INCV is INTEGER
  • The increment between elements of v. INCV <> 0 🫶
• TAU — TAU is DOUBLE PRECISION
  • The value tau in the representation of P.
• C1 — C1 is DOUBLE PRECISION array, dimension
  • (LDC,N) if SIDE = 'L'
  • (M,1) if SIDE = 'R'

On entry, the n-vector C1 if SIDE = 'L', or the m-vector C1 if SIDE = 'R'.

On exit, the first row of P*C if SIDE = 'L', or the first column of C*P if SIDE = 'R'.

• C2 — C2 is DOUBLE PRECISION array, dimension
  • (LDC, N) if SIDE = 'L'
  • (LDC, N-1) if SIDE = 'R'

On entry, the (m - 1) x n matrix C2 if SIDE = 'L', or the m x (n - 1) matrix C2 if SIDE = 'R'.

On exit, rows 2:m of P*C if SIDE = 'L', or columns 2:m of C*P if SIDE = 'R'.

• LDC — LDC is INTEGER
  • The leading dimension of the arrays C1 and C2. LDC >= (1,M).
• WORK — WORK is DOUBLE PRECISION array, dimension
  • (N) if SIDE = 'L'
  • (M) if SIDE = 'R'

👑 Author

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 150 of file dlatzm.f.

🌈 Author

Generated automatically by Doxygen for LAPACK from the source code.

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okay that’s the whole page, bestie! This iconic little artifact is LAPACK Version 3.12.0, living at SRC/DEPRECATED/dlatzm.f(3). mwah 💋🎀✨