SRC/sopgtr.f(3)

💅 SRC/sopgtr.f 💅

from the Library Functions Manual — okay bestie, this one is all about SOPGTR, no cap ✨

🌸 NAME 🌸

SRC/sopgtr.f

🐚 SYNOPSIS 🐚

💖 Functions/Subroutines 💖

• subroutine sopgtr (uplo, n, ap, tau, q, ldq, work, info) — SOPGTR

🦋 Function/Subroutine Documentation 🦋

subroutine sopgtr (character uplo, integer n, real, dimension( * ) ap, real, dimension( * ) tau, real, dimension( ldq, * ) q, integer ldq, real, dimension( * ) work, integer info)

SOPGTR

🎯 Purpose:

Okay so SOPGTR generates a real orthogonal matrix Q which is defined as the product of n-1 elementary reflectors H(i) of order n, as returned by SSPTRD using packed storage:

if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),

if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).

🧩 Parameters

• UPLO is CHARACTER*1
  • = 'U': Upper triangular packed storage used in previous call to SSPTRD;
  • = 'L': Lower triangular packed storage used in previous call to SSPTRD.
• N is INTEGER
  • The order of the matrix Q. N >= 0.
• AP is REAL array, dimension (N*(N+1)/2)
  • The vectors which define the elementary reflectors, as returned by SSPTRD.
• TAU is REAL array, dimension (N-1)
  • TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SSPTRD.
• Q is REAL array, dimension (LDQ,N)
  • The N-by-N orthogonal matrix Q.
• LDQ is INTEGER
  • The leading dimension of the array Q. LDQ >= max(1,N).
• WORK is REAL array, dimension (N-1)
• INFO is INTEGER
  • = 0: successful exit
  • < 0: if INFO = -i, the i-th argument had an illegal value

💖 Author

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

Definition at line 113 of file sopgtr.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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That’s the whole page, bestie! Signing off with LAPACK Version 3.12.0 and SRC/sopgtr.f(3) 💖✨