TESTING/EIG/dbdt02.f(3)

💅 NAME 💅

okay so bestie, this is the manual page for TESTING/EIG/dbdt02.f — yep, the TESTING/EIG/dbdt02.f(3) manual-name situation. It documents the Fortran subroutine dbdt02, and it’s giving LAPACK testing energy. periodt. 💖

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✨ SYNOPSIS ✨

Functions/Subroutines

       subroutine dbdt02 (m, n, b, ldb, c, ldc, u, ldu, work, resid)
           DBDT02

One subroutine, one very specific job. slay. 🎀

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🛠️ Function/Subroutine Documentation 🛠️

   subroutine dbdt02 (integer m, integer n, double precision, dimension( ldb, *
       ) b, integer ldb, double precision, dimension( ldc, * ) c, integer ldc,
       double precision, dimension( ldu, * ) u, integer ldu, double precision,
       dimension( * ) work, double precision resid)
       DBDT02

🎯 Purpose 🎯

DBDT02 tests the change of basis C = U**H * B by computing the residual:

RESID = norm(B - U * C) / ( max(m,n) * norm(B) * EPS ),

where B and C are M by N matrices, U is an M by M orthogonal matrix, and EPS is the machine precision. literally the whole vibe check for that change of basis. 🦋

🧮 Parameters 🧮

• M — M is INTEGER. It’s the number of rows of the matrices B and C and the order of the matrix Q. yes, Q — keep it exactly like that, bestie. 💅
• N — N is INTEGER. The number of columns of the matrices B and C.
• B — B is DOUBLE PRECISION array, dimension (LDB,N). The m by n matrix B.
• LDB — LDB is INTEGER. The leading dimension of the array B. LDB >= max(1,M).
• C — C is DOUBLE PRECISION array, dimension (LDC,N). The m by n matrix C, assumed to contain U**H * B.
• LDC — LDC is INTEGER. The leading dimension of the array C. LDC >= max(1,M).
• U — U is DOUBLE PRECISION array, dimension (LDU,M). The m by m orthogonal matrix U.
• LDU — LDU is INTEGER. The leading dimension of the array U. LDU >= max(1,M).
• WORK — WORK is DOUBLE PRECISION array, dimension (M).
• RESID — RESID is DOUBLE PRECISION. RESID = norm(B - U * C) / ( max(m,n) * norm(B) * EPS ).

👑 Author 👑

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

Definition at line 111 of file dbdt02.f.

📝 Author 📝

Generated automatically by Doxygen for LAPACK from the source code.

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💖 cute sign-off, bestie: this footer situation is LAPACK Version 3.12.0, and the manual source path is TESTING/EIG/dbdt02.f(3). no extra date shown on the footer, so we’re not inventing one — fr fr. slay and goodbye. 💅✨