/home/abui...hr_col02.f(3)

πŸ“¦ version 3.12.0, in opensuse-leap 16.0

πŸ’… DORHR_COL02 πŸ’…

okay so bestie, this is a Library Functions Manual page for /home/abui...hr_col02.f(3) β€” and it's all about the DORHR_COL02 subroutine. It's giving "LAPACK test routine that checks the checkers," and honestly? iconic. πŸ’–


πŸ’– NAME πŸ’–

The name is literally this whole path, no edits:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/TESTING/LIN/dorhr_col02.f


✨ SYNOPSIS ✨

πŸ¦‹ Functions/Subroutines

       subroutine DORHR_COL02 (m, n, mb1, nb1, nb2, result)
           DORHR_COL02

🌸 Function/Subroutine Documentation 🌸

The signature, preserved exactly:

   subroutine DORHR_COL02 (integer m, integer n, integer mb1, integer nb1,
       integer nb2, double precision, dimension(6) result)
       DORHR_COL02

πŸŽ€ Purpose

DORHR_COL02 tests DORGTSQR_ROW and DORHR_COL inside DGETSQRHRT (which calls DLATSQR, DORGTSQR_ROW, and DORHR_COL) using DGEMQRT. So yeah β€” DLATSQR (part of DGEQR) and DGEMQRT (part of DGEMQR) have to be tested before this test. No skipping the prerequisites, bestie. πŸ’…

🌈 Parameters

πŸ’œ M

M is INTEGER. Number of rows in test matrix.

πŸ’œ N

N is INTEGER. Number of columns in test matrix.

πŸ’œ MB1

MB1 is INTEGER. Number of row in row block in an input test matrix.

πŸ’œ NB1

NB1 is INTEGER. Number of columns in column block an input test matrix.

πŸ’œ NB2

NB2 is INTEGER. Number of columns in column block in an output test matrix.

πŸ’œ RESULT

RESULT is DOUBLE PRECISION array, dimension (6). Results of each of the six tests below.

Okay so the setup is giving a whole little matrix cinematic universe:

  • A is a m-by-n test input matrix to be factored, so that:
A = Q_gr * ( R )
           ( 0 ),
  • Q_qr is an implicit m-by-m orthogonal Q matrix, the result of factorization in blocked WY-representation, stored in ZGEQRT output format.
  • R is a n-by-n upper-triangular matrix.
  • 0 is a (m-n)-by-n zero matrix.
  • Q is an explicit m-by-m orthogonal matrix Q = Q_gr * I.
  • C is an m-by-n random matrix.
  • D is an n-by-m random matrix.

The six tests are:

RESULT(1) = |R - (Q**H) * A| / ( eps * m * |A| )
  is equivalent to test for | A - Q * R | / (eps * m * |A|),

RESULT(2) = |I - (Q**H) * Q| / ( eps * m ),

RESULT(3) = | Q_qr * C - Q * C | / (eps * m * |C|),

RESULT(4) = | (Q_gr**H) * C - (Q**H) * C | / (eps * m * |C|)

RESULT(5) = | D * Q_qr - D * Q | / (eps * m * |D|)

RESULT(6) = | D * (Q_qr**H) - D * (Q**H) | / (eps * m * |D|),

where:

  • Q_qr * C, (Q_gr**H) * C, D * Q_qr, D * (Q_qr**H) are computed using DGEMQRT.
  • Q * C, (Q**H) * C, D * Q, D * (Q**H) are computed using DGEMM.

πŸ‘‘ Author

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

Definition at line 119 of file dorhr_col02.f.


πŸ‘‘ Author

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and that's the whole page, bestie! This one is from LAPACK Version 3.12.0, with footer path /home/abui...hr_col02.f(3). No date printed on it, so I'm not inventing one β€” just pure LAPACK version energy. bye! πŸ’…βœ¨πŸ¦‹

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