BLAS/SRC/stpsv.f(3)

🌸 NAME 🌸

okay so bestie, this is the BLAS/SRC/stpsv.f(3) page from the Library Functions Manual — and it's all about STPSV, a BLAS routine that solves triangular systems stored in packed form. iconique linear algebra behavior, no cap 💅

✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

subroutine stpsv (uplo, trans, diag, n, ap, x, incx)
    STPSV

💖 Function/Subroutine Documentation 💖

subroutine stpsv (character uplo, character trans, character diag, integer
    n, real, dimension(*) ap, real, dimension(*) x, integer incx)
    STPSV

🌟 Purpose 🌟

STPSV solves one of these systems of equations:

A*x = b,   or   A**T*x = b,

where b and x are n element vectors and A is an n by n unit, or non-unit, upper or lower triangular matrix, supplied in packed form.

⚠️ No test for singularity or near-singularity is included in this routine. Such tests must be performed before calling this routine. seriously bestie, check that yourself first 😭

🎛️ Parameters 🎛️

• UPLO — CHARACTER*1. On entry, UPLO specifies whether the matrix is an upper or lower triangular matrix as follows:
  • UPLO = 'U' or 'u' — A is an upper triangular matrix.
  • UPLO = 'L' or 'l' — A is a lower triangular matrix.
• TRANS — CHARACTER*1. On entry, TRANS specifies the equations to be solved as follows:
  • TRANS = 'N' or 'n' — A*x = b.
  • TRANS = 'T' or 't' — A**T*x = b.
  • TRANS = 'C' or 'c' — A**T*x = b.
• DIAG — CHARACTER*1. On entry, DIAG specifies whether or not A is unit triangular as follows:
  • DIAG = 'U' or 'u' — A is assumed to be unit triangular.
  • DIAG = 'N' or 'n' — A is not assumed to be unit triangular.
• N — INTEGER. On entry, N specifies the order of the matrix A. N must be at least zero.
• AP — REAL array, dimension at least ( ( n*( n + 1 ) )/2 ). Before entry with UPLO = 'U' or 'u', the array AP must contain the upper triangular matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 ) respectively, and so on. Before entry with UPLO = 'L' or 'l', the array AP must contain the lower triangular matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respectively, and so on. Note that when DIAG = 'U' or 'u', the diagonal elements of A are not referenced, but are assumed to be unity.
• X — REAL array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the n element right-hand side vector b. On exit, X is overwritten with the solution vector x.
• INCX — INTEGER. On entry, INCX specifies the increment for the elements of X. INCX must not be zero.

🌈 Author 🌈

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

🔥 Further Details 🔥

Level 2 Blas routine.

-- Written on 22-October-1986.
   Jack Dongarra, Argonne National Lab.
   Jeremy Du Croz, Nag Central Office.
   Sven Hammarling, Nag Central Office.
   Richard Hanson, Sandia National Labs.

📌 Definition at line 143 of file stpsv.f 📌

Definition at line 143 of file stpsv.f.

🧚 Author 🧚

Generated automatically by Doxygen for LAPACK from the source code.

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okay bestie, that's the whole page 💅✨ Source/version sign-off: LAPACK, Version 3.12.0, page BLAS/SRC/stpsv.f(3). The footer doesn't give me a separate date, so I'm not inventing one — the only date on the page is 22-October-1986 in Further Details 🫶🎀