/home/abui.../dsyconv.f(3)

🦋 NAME 🦋

ok so bestie, this whole page is about one file path and one file only:

That's it. That's the name. It's literally giving "I live at this exact address, don't @ me" 💅 (and yeah, this is page `dsyconv.f(3)` from the LAPACK Library Functions Manual, hi 👋)

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# ✨ SYNOPSIS ✨

## 🫶 Functions/Subroutines

- **`subroutine DSYCONV (uplo, way, n, a, lda, ipiv, e, info)`** — the one and only, the main character herself: `DSYCONV` 🌟

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# 💖 Function/Subroutine Documentation 💖

## 🎀 subroutine DSYCONV

Here's the full signature, no cap, exactly as written:

subroutine DSYCONV (character uplo, character way, integer n, double precision, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, double precision, dimension( * ) e, integer info)

and yes, the name again, because she's iconic like that: `DSYCONV` 👑

### 🌸 Purpose:

!> !> DSYCONV convert A given by TRF into L and D and vice-versa. !> Get Non-diag elements of D (returned in workspace) and !> apply or reverse permutation done in TRF. !>

So basically: you hand her a matrix `A` that came out of TRF, and she flips it into `L` and `D` — or does the whole thing in reverse. She also grabs the non-diagonal elements of `D` (those get returned in workspace, bestie) and applies or reverses the permutation that TRF did. She's a two-way street and she's slaying both directions 💫

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## 🌈 Parameters

### `UPLO`

!> UPLO is CHARACTER*1 !> Specifies whether the details of the factorization are stored !> as an upper or lower triangular matrix. !> = 'U': Upper triangular, form is A = U*D*UT; !> = 'L': Lower triangular, form is A = L*D*LT. !>

so `UPLO` is a `CHARACTER*1` and it tells her whether the factorization details are chilling as an upper or lower triangular matrix:

- `'U'` → upper triangular, form is `A = U*D*U**T`
- `'L'` → lower triangular, form is `A = L*D*L**T`

pick your fighter 🥊

### `WAY`

!> WAY is CHARACTER*1 !> = 'C': Convert !> = 'R': Revert !>

`WAY` is a `CHARACTER*1`, and it's literally just the direction of travel:

- `'C'` → Convert
- `'R'` → Revert

forward or backward, choose your adventure 🦋

### `N`

!> N is INTEGER !> The order of the matrix A. N >= 0. !>

`N` is `INTEGER`, the order of the matrix `A`. Constraint: `N >= 0.` (zero is allowed, she's inclusive 💜)

### `A`

!> A is DOUBLE PRECISION array, dimension (LDA,N) !> The block diagonal matrix D and the multipliers used to !> obtain the factor U or L as computed by DSYTRF. !>

`A` is a `DOUBLE PRECISION` array, dimension `(LDA,N)`. She holds the block diagonal matrix `D` plus the multipliers used to obtain the factor `U` or `L` as computed by `DSYTRF`. she contains multitudes ✨

### `LDA`

!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,N). !>

`LDA` is `INTEGER`, the leading dimension of the array `A`. Constraint: `LDA >= max(1,N).` don't skimp on it 🙈

### `IPIV`

!> IPIV is INTEGER array, dimension (N) !> Details of the interchanges and the block structure of D !> as determined by DSYTRF. !>

`IPIV` is an `INTEGER` array, dimension `(N)`. It's carrying the details of the interchanges and the block structure of `D`, as determined by `DSYTRF`. the receipts, basically 🧾

### `E`

!> E is DOUBLE PRECISION array, dimension (N) !> E stores the supdiagonal/subdiagonal of the symmetric 1-by-1 !> or 2-by-2 block diagonal matrix D in LDLT. !>

`E` is a `DOUBLE PRECISION` array, dimension `(N)`, and it stores the supdiagonal/subdiagonal of the symmetric 1-by-1 or 2-by-2 block diagonal matrix `D` in LDLT. tiny but crucial, lowkey the whole vibe 🔥

### `INFO`

!> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument had an illegal value !>

`INFO` is `INTEGER` and it's the mood report:

- `= 0:` successful exit 🎉
- `< 0:` if `INFO = -i`, the i-th argument had an illegal value 💀 (so like, check your args bestie)

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## 👑 Author

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

all the legends, credited properly 🫶

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## ⭐ Definition

Definition at line `113` of file `dsyconv.f`.

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# 🌸 Author 🌸

Generated automatically by Doxygen for LAPACK from the source code. (yes the robots wrote this bit, we respect the robots 🤖💅)

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ok and that's the whole page!! 🎀 this came from LAPACK, <pink>Version 3.12.0</pink>, and the footer date/source line lives right here at the very bottom of the original doc — so consider this your cute little sign-off: <purple>LAPACK, Version 3.12.0</purple> ✨ bye bestie, go convert something 💖