DSPGST(3)

💅 DSPGST(3) — Library Functions Manual energy 💅

okay so welcome to the Library Functions Manual page for DSPGST(3), bestie. Header path vibe: /home/abui...RC/dspgst.f(3). This is the whole DSPGST situation, and it’s lowkey iconic. ✨

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✨ NAME ✨

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dspgst.f

That’s the file. No cap. 🫶

🌈 SYNOPSIS 🌈

🧚 Functions/Subroutines 🧚

• subroutine DSPGST (itype, uplo, n, ap, bp, info) — the subroutine synopsis line, main character energy.
• DSPGST — the name again, periodt.

🎀 Function/Subroutine Documentation 🎀

subroutine DSPGST (integer itype, character uplo, integer n, double
    precision, dimension( * ) ap, double precision, dimension( * ) bp,
    integer info)
    DSPGST

🌟 Purpose 🌟

okay so here’s the tea: DSPGST reduces a real symmetric-definite generalized eigenproblem to standard form, using packed storage. That’s the whole mission. 💖

• If ITYPE = 1, the problem is A*x = lambda*B*x, and A is overwritten by inv(U**T)*A*inv(U) or inv(L)*A*inv(L**T).
• If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or B*A*x = lambda*x, and A is overwritten by U*A*U**T or L**T*A*L.
• B must have been previously factorized as U**T*U or L*L**T by DPPTRF.

💜 Parameters 💜

• ITYPE — ITYPE is INTEGER
  • = 1: compute inv(U**T)*A*inv(U) or inv(L)*A*inv(L**T);
  • = 2 or 3: compute U*A*U**T or L**T*A*L.
• UPLO — UPLO is CHARACTER*1
  • = 'U': Upper triangle of A is stored and B is factored as U**T*U;
  • = 'L': Lower triangle of A is stored and B is factored as L*L**T.
• N — N is INTEGER. The order of the matrices A and B. N >= 0.
• AP — AP is DOUBLE PRECISION array, dimension (N*(N+1)/2). On entry, the upper or lower triangle of the symmetric matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows:

if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.

On exit, if INFO = 0, the transformed matrix, stored in the same format as A.

• BP — BP is DOUBLE PRECISION array, dimension (N*(N+1)/2). The triangular factor from the Cholesky factorization of B, stored in the same format as A, as returned by DPPTRF.
• 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 112 of file dspgst.f.

💀 Author 💀

Generated automatically by Doxygen for LAPACK from the source code.

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That’s the whole page, bestie! Footer vibe check: LAPACK Version 3.12.0, /home/abui...RC/dspgst.f(3). Byeee 💖✨🎀