/home/abui.../dgemlqt.f(3)

🎀 NAME

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dgemlqt.f — yup, that's literally the whole NAME entry, bestie. This page is from the Library Functions Manual, and it's here to explain DGEMLQT with zero chill and full LAPACK energy. 💅

✨ SYNOPSIS

Functions/Subroutines

subroutine DGEMLQT (side, trans, m, n, k, mb, v, ldv, t, ldt, c, ldc,
     work, info)

DGEMLQT

🦋 Function/Subroutine Documentation

💖 DGEMLQT

subroutine DGEMLQT (character side, character trans, integer m, integer n,
     integer k, integer mb, double precision, dimension( ldv, * ) v, integer
     ldv, double precision, dimension( ldt, * ) t, integer ldt, double
     precision, dimension( ldc, * ) c, integer ldc, double precision,
     dimension( * ) work, integer info)

DGEMLQT

🎯 Purpose:

Okay so DGEMLQT overwrites the general real M-by-N matrix C with these exact moves, no cap:

                SIDE = 'L'     SIDE = 'R'
TRANS = 'N':      Q C            C Q
TRANS = 'T':   Q**T C            C Q**T

where Q is a real orthogonal matrix defined as the product of K elementary reflectors:

Q = H(1) H(2) . . . H(K) = I - V T V**T

generated using the compact WY representation as returned by DGELQT.

Q is of order M if SIDE = 'L' and of order N if SIDE = 'R'. Periodt. ✨

🌸 Parameters

• SIDE — SIDE is CHARACTER*1.
  • = 'L': apply Q or Q**T from the Left;
  • = 'R': apply Q or Q**T from the Right.
• TRANS — TRANS is CHARACTER*1.
  • = 'N': No transpose, apply Q;
  • = 'C': Transpose, apply Q**T.
• M — M is INTEGER. The number of rows of the matrix C. M >= 0.
• N — N is INTEGER. The number of columns of the matrix C. N >= 0.
• K — K is INTEGER. The number of elementary reflectors whose product defines the matrix Q.
  • If SIDE = 'L', M >= K >= 0;
  • if SIDE = 'R', N >= K >= 0.
• MB — MB is INTEGER. The block size used for the storage of T. K >= MB >= 1. This must be the same value of MB used to generate T in DGELQT.
• V — V is DOUBLE PRECISION array, dimension
  • (LDV,M) if SIDE = 'L',
  • (LDV,N) if SIDE = 'R'.

The i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by DGELQT in the first K rows of its array argument A.

• LDV — LDV is INTEGER. The leading dimension of the array V. LDV >= max(1,K).
• T — T is DOUBLE PRECISION array, dimension (LDT,K). The upper triangular factors of the block reflectors as returned by DGELQT, stored as a MB-by-K matrix.
• LDT — LDT is INTEGER. The leading dimension of the array T. LDT >= MB.
• C — C is DOUBLE PRECISION array, dimension (LDC,N).
  • On entry, the M-by-N matrix C.
  • On exit, C is overwritten by Q C, Q**T C, C Q**T or C Q.
• LDC — LDC is INTEGER. The leading dimension of the array C. LDC >= max(1,M).
• WORK — WORK is DOUBLE PRECISION array. The dimension of WORK is N*MB if SIDE = 'L', or M*MB if SIDE = 'R'.
• INFO — 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 166 of file dgemlqt.f.

🤖 Author

Generated automatically by Doxygen for LAPACK from the source code.

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💖 That's the whole page, bestie — LAPACK Version 3.12.0, /home/abui.../dgemlqt.f(3), caught by Doxygen on the way out. Slay. 💅✨