SRC/zgttrs.f(3)

💖 SRC/zgttrs.f 💖

okay so welcome to the Library Functions Manual page for SRC/zgttrs.f, bestie — this is the ZGTTRS zone and it’s lowkey iconic. 💅

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🌸 NAME 🌸

SRC/zgttrs.f

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✨ SYNOPSIS ✨

🌈 Functions/Subroutines 🌈

   subroutine zgttrs (trans, n, nrhs, dl, d, du, du2, ipiv, b, ldb, info)

ZGTTRS

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🧚 Function/Subroutine Documentation 🧚

⭐ subroutine zgttrs ⭐

   subroutine zgttrs (character trans, integer n, integer nrhs, complex*16,
       dimension( * ) dl, complex*16, dimension( * ) d, complex*16, dimension(
       * ) du, complex*16, dimension( * ) du2, integer, dimension( * ) ipiv,
       complex*16, dimension( ldb, * ) b, integer ldb, integer info)

ZGTTRS

💫 Purpose 💫

okay so ZGTTRS solves one of these systems of equations:

A * X = B,  A**T * X = B,  or  A**H * X = B,

with a tridiagonal matrix A using the LU factorization computed by ZGTTRF. periodt. 🫶

🎀 Parameters 🎀

• TRANS — is CHARACTER*1. It specifies the form of the system of equations:
  • = 'N': A * X = B (No transpose)
  • = 'T': A**T * X = B (Transpose)
  • = 'C': A**H * X = B (Conjugate transpose)
• N — is INTEGER. The order of the matrix A.
• NRHS — is INTEGER. The number of right hand sides, i.e., the number of columns of the matrix B. NRHS >= 0.
• DL — is COMPLEX*16 array, dimension (N-1). The (n-1) multipliers that define the matrix L from the LU factorization of A.
• D — is COMPLEX*16 array, dimension (N). The n diagonal elements of the upper triangular matrix U from the LU factorization of A.
• DU — is COMPLEX*16 array, dimension (N-1). The (n-1) elements of the first super-diagonal of U.
• DU2 — is COMPLEX*16 array, dimension (N-2). The (n-2) elements of the second super-diagonal of U.
• IPIV — is INTEGER array, dimension (N). The pivot indices; for 1 <= i <= n, row i of the matrix was interchanged with row IPIV(i). IPIV(i) will always be either i or i+1; IPIV(i) = i indicates a row interchange was not required.
• B — is COMPLEX*16 array, dimension (LDB,NRHS). On entry, the matrix of right hand side vectors B. On exit, B is overwritten by the solution vectors X.
• LDB — is INTEGER. The leading dimension of the array B. LDB >= max(1,N).
• INFO — is INTEGER:
  • = 0: successful exit
  • < 0: if INFO = -k, the k-th argument had an illegal value

👑 Author 👑

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

Definition at line 136 of file zgttrs.f.

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👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code.

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