lapackfix(3)

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version 1.1.2 · 3 versions
, in fedora 43

✨ lapackfix — the glow-up era of LAPACK 💅

okay so bestie, we're in the MEPACK manual, section 3, and this page is literally just called lapackfix. it's giving "bugfix delivery service" and honestly? iconic.

🌸 NAME 🌸

lapackfix — Fixed LAPACK routines

  • Bugfix versions of LAPACK routines. 🎀

🦋 SYNOPSIS 🦋

✨ Functions ✨

here's the whole squad, one subroutine at a time. no skips, no cuts, we're doing all of them:

  • subroutine cgetc2x (n, a, lda, ipiv, jpiv, info) CGETC2X computes the LU factorization with complete pivoting of the general n-by-n matrix. 💖
  • subroutine dgetc2x (n, a, lda, ipiv, jpiv, info) DGETC2X computes the LU factorization with complete pivoting of the general n-by-n matrix. 💖
  • subroutine sgetc2x (n, a, lda, ipiv, jpiv, info) SGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix. 💖
  • subroutine zgetc2 (n, a, lda, ipiv, jpiv, info) ZGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix. 💖
not me noticing the names are almost a matching set but not quite. we are NOT fixing that, we are reporting it exactly as it is. the facts do not move, periodt. 💀

🌈 Detailed Description 🌈

Bugfix versions of LAPACK routines. ✨

so here's the tea. During the development of MEPACK, some LAPACK routines show some bugs since they are used differently in MEPACK than in LAPACK. 🫠

Therefore, MEPACK comes with patched version of this routines in order to avoid bugs. 🩹

Newer LAPACK versions include the bugfixes as well but we do not rely on this. 👑

bestie listen: this is the whole reason this page exists. MEPACK said "we're not trusting upstream to have our back" and shipped its own patched copies. main character energy fr fr. 🎀

<divider>

okay that's the vibe for this part — more of the page is still loading, so stay with me. 🦋

💅 FUNCTION DOCUMENTATION 💅

Okay bestie, buckle up, because this is the part where we meet the whole squad — four little subroutines that all do the same iconique thing but for different number flavors. Same energy, different data types. Let's go 🦋

🌸 subroutine cgetc2x 🌸

subroutine cgetc2x (integer n, complex, dimension( lda, * ) a, integer lda,
    integer, dimension( * ) ipiv, integer, dimension( * ) jpiv, integer
    info)

CGETC2X computes the LU factorization with complete pivoting of the general n-by-n matrix. 💖

✨ Purpose ✨

CGETC2 computes an LU factorization, using complete pivoting, of the n-by-n matrix A. The factorization has the form A = P * L * U * Q, where P and Q are permutation matrices, L is lower triangular with unit diagonal elements and U is upper triangular. 🎀

This routine contains a fixed version of the forward/backward substitution if an old version of LAPACK is used. 👑

This is a level 1 BLAS version of the algorithm. ⭐

🌈 Parameters 🌈

  • N — N is INTEGER. The order of the matrix A. N >= 0. 🫶
  • A — A is COMPLEX array, dimension (LDA, N). On entry, the n-by-n matrix to be factored. On exit, the factors L and U from the factorization A = P*L*U*Q; the unit diagonal elements of L are not stored. If U(k, k) appears to be less than SMIN, U(k, k) is given the value of SMIN, giving a non singular perturbed system. 😭
  • LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1, N). 💅
  • IPIV — IPIV is INTEGER array, dimension (N). The pivot indices; for 1 <= i <= N, row i of the matrix has been interchanged with row IPIV(i). 🔥
  • JPIV — JPIV is INTEGER array, dimension (N). The pivot indices; for 1 <= j <= N, column j of the matrix has been interchanged with column JPIV(j). 🔥
  • INFO — INFO is INTEGER.
    • == 0: successful exit ✨
    • > 0: if INFO = k, U(k, k) is likely to produce overflow if one tries to solve for x in Ax = b. So U is perturbed to avoid the overflow. 💀

👑 Author 👑

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

🎀 Date 🎀

October 2025

🧚 Contributors 🧚

Bo Kagstrom and Peter Poromaa, Department of Computing Science, Umea University, S-901 87 Umea, Sweden.

Definition at line 115 of file cgetc2x.f90. 🌸

🦋 subroutine dgetc2x 🦋

subroutine dgetc2x (integer n, double precision, dimension( lda, * ) a,
    integer lda, integer, dimension( * ) ipiv, integer, dimension( * ) jpiv,
    integer info)

DGETC2X computes the LU factorization with complete pivoting of the general n-by-n matrix. 💖

✨ Purpose ✨

DGETC2 computes an LU factorization with complete pivoting of the n-by-n matrix A. The factorization has the form A = P * L * U * Q, where P and Q are permutation matrices, L is lower triangular with unit diagonal elements and U is upper triangular. 🎀

This routine contains a fixed version of the forward/backward substitution if an old version of LAPACK is used. 👑

This is the Level 2 BLAS algorithm. ⭐

🌈 Parameters 🌈

  • N — N is INTEGER. The order of the matrix A. N >= 0. 🫶
  • A — A is DOUBLE PRECISION array, dimension (LDA, N). On entry, the n-by-n matrix A to be factored. On exit, the factors L and U from the factorization A = P*L*U*Q; the unit diagonal elements of L are not stored. If U(k, k) appears to be less than SMIN, U(k, k) is given the value of SMIN, i.e., giving a non singular perturbed system. 😭
  • LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N). 💅
  • IPIV — IPIV is INTEGER array, dimension (N). The pivot indices; for 1 <= i <= N, row i of the matrix has been interchanged with row IPIV(i). 🔥
  • JPIV — JPIV is INTEGER array, dimension (N). The pivot indices; for 1 <= j <= N, column j of the matrix has been interchanged with column JPIV(j). 🔥
  • INFO — INFO is INTEGER.
    • == 0: successful exit ✨
    • > 0: if INFO = k, U(k, k) is likely to produce overflow if we try to solve for x in Ax = b. So U is perturbed to avoid the overflow. 💀

👑 Author 👑

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

🎀 Date 🎀

October 2025

🧚 Contributors 🧚

Bo Kagstrom and Peter Poromaa, Department of Computing Science, Umea University, S-901 87 Umea, Sweden.

Definition at line 115 of file dgetc2x.f90. 🦋

🌸 subroutine sgetc2x 🌸

subroutine sgetc2x (integer n, real, dimension( lda, * ) a, integer lda,
    integer, dimension( * ) ipiv, integer, dimension( * ) jpiv, integer
    info)

SGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix. 💖

✨ Purpose ✨

SGETC2 computes an LU factorization with complete pivoting of the n-by-n matrix A. The factorization has the form A = P * L * U * Q, where P and Q are permutation matrices, L is lower triangular with unit diagonal elements and U is upper triangular. 🎀

This routine contains a fixed version of the forward/backward substitution if an old version of LAPACK is used. 👑

This is the Level 2 BLAS algorithm. ⭐

🌈 Parameters 🌈

  • N — N is INTEGER. The order of the matrix A. N >= 0. 🫶
  • A — A is REAL array, dimension (LDA, N). On entry, the n-by-n matrix A to be factored. On exit, the factors L and U from the factorization A = P*L*U*Q; the unit diagonal elements of L are not stored. If U(k, k) appears to be less than SMIN, U(k, k) is given the value of SMIN, i.e., giving a non singular perturbed system. 😭
  • LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,N). 💅
  • IPIV — IPIV is INTEGER array, dimension (N). The pivot indices; for 1 <= i <= N, row i of the matrix has been interchanged with row IPIV(i). 🔥
  • JPIV — JPIV is INTEGER array, dimension (N). The pivot indices; for 1 <= j <= N, column j of the matrix has been interchanged with column JPIV(j). 🔥
  • INFO — INFO is INTEGER.
    • == 0: successful exit ✨
    • > 0: if INFO = k, U(k, k) is likely to produce overflow if we try to solve for x in Ax = b. So U is perturbed to avoid the overflow. 💀

👑 Author 👑

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

🎀 Date 🎀

October 2025

🧚 Contributors 🧚

Bo Kagstrom and Peter Poromaa, Department of Computing Science, Umea University, S-901 87 Umea, Sweden.

Definition at line 115 of file sgetc2x.f90. 🌸

🦋 subroutine zgetc2 🦋

subroutine zgetc2 (integer n, complex(kind=kind(1.0d0)), dimension( lda, * )
    a, integer lda, integer, dimension( * ) ipiv, integer, dimension( * )
    jpiv, integer info)

ZGETC2 computes the LU factorization with complete pivoting of the general n-by-n matrix. 💖

✨ Purpose ✨

ZGETC2 computes an LU factorization, using complete pivoting, of the n-by-n matrix A. The factorization has the form A = P * L * U * Q, where P and Q are permutation matrices, L is lower triangular with unit diagonal elements and U is upper triangular. 🎀

This routine contains a fixed version of the forward/backward substitution if an old version of LAPACK is used. 👑

This is a level 1 BLAS version of the algorithm. ⭐

🌈 Parameters 🌈

  • N — N is INTEGER. The order of the matrix A. N >= 0. 🫶
  • A — A is COMPLEX*16 array, dimension (LDA, N). On entry, the n-by-n matrix to be factored. On exit, the factors L and U from the factorization A = P*L*U*Q; the unit diagonal elements of L are not stored. If U(k, k) appears to be less than SMIN, U(k, k) is given the value of SMIN, giving a non singular perturbed system. 😭
  • LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1, N). 💅
  • IPIV — IPIV is INTEGER array, dimension (N). The pivot indices; for 1 <= i <= N, row i of the matrix has been interchanged with row IPIV(i). 🔥
  • JPIV — JPIV is INTEGER array, dimension (N). The pivot indices; for 1 <= j <= N, column j of the matrix has been interchanged with column JPIV(j). 🔥
  • INFO — INFO is INTEGER.
    • == 0: successful exit ✨
    • > 0: if INFO = k, U(k, k) is likely to produce overflow if one tries to solve for x in Ax = b. So U is perturbed to avoid the overflow. 💀

👑 Author 👑

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

🎀 Date 🎀

October 2025

🧚 Contributors 🧚

Bo Kagstrom and Peter Poromaa, Department of Computing Science, Umea University, S-901 87 Umea, Sweden.

Definition at line 115 of file zgetc2x.f90. 🦋

👑 AUTHOR 👑

Generated automatically by Doxygen for MEPACK from the source code. 🤖✨ (not me being obsessed with auto-generated docs, it's giving effortless)

okay that's the whole page bestie!! this is Version 1.1.2, dated Thu Oct 9 2025 00:00:00, and you've been reading lapackfix(3) 💖 go forth and pivot completely, no cap 🫶✨
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