SRC/dlamrg.f(3)

🦋 SRC/dlamrg.f(3) 🦋

okay bestie, welcome to the Library Functions Manual ✨ this one's a Fortran file page and honestly? it ate. it's giving "small subroutine, huge main character energy." let's get into it 💅

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🌸 NAME 🌸

SRC/dlamrg.f — no cap, that's literally the whole name, she's lowkey mysterious like that 🎀

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✨ SYNOPSIS ✨

🫶 Functions/Subroutines

• subroutine dlamrg (n1, n2, a, dtrd1, dtrd2, index) — DLAMRG creates a permutation list to merge the entries of two independently sorted sets into a single set sorted in ascending order. periodt. 🔥

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👑 Function/Subroutine Documentation 👑

💖 subroutine dlamrg (integer n1, integer n2, double precision, dimension( * ) a, integer dtrd1, integer dtrd2, integer, dimension( * ) index)

DLAMRG creates a permutation list to merge the entries of two independently sorted sets into a single set sorted in ascending order. (yes I said it twice, because she said it twice, and because it's iconic 💅)

⭐ Purpose:

!>
!> DLAMRG will create a permutation list which will merge the elements
!> of A (which is composed of two independently sorted sets) into a
!> single set which is sorted in ascending order.
!>

like literally she just makes you a lil map so you can read your two sorted lists as one sorted list. tiny function, massive slay 🌈

🎀 Parameters

• N1

!>          N1 is INTEGER
!>

• N2

!>          N2 is INTEGER
!>         These arguments contain the respective lengths of the two
!>         sorted lists to be merged.
!>

so like, N1 and N2 are just "how long is list one, how long is list two" — the length besties 📏

• A

!>          A is DOUBLE PRECISION array, dimension (N1+N2)
!>         The first N1 elements of A contain a list of numbers which
!>         are sorted in either ascending or descending order.  Likewise
!>         for the final N2 elements.
!>

so the first N1 slots are one sorted list and the last N2 slots are the other sorted list, and each one can be sorted either way — no judgement, ascending or descending, both valid 💜

• DTRD1

!>          DTRD1 is INTEGER
!>

• DTRD2

!>          DTRD2 is INTEGER
!>         These are the strides to be taken through the array A.
!>         Allowable strides are 1 and -1.  They indicate whether a
!>         subset of A is sorted in ascending (DTRDx = 1) or descending

!> (DTRDx = -1) order. !>

> ⚠️ heads up bestie: the only allowable strides are `1` and `-1`. don't get cute and pass something else, fr fr. `1` means that set is ascending, `-1` means it's descending. that's the whole vibe check 🕵️

- **`INDEX`**

!> INDEX is INTEGER array, dimension (N1+N2) !> On exit this array will contain a permutation such that !> if B( I ) = A( INDEX( I ) ) for I=1,N1+N2, then B will be !> sorted in ascending order. !>

this is the payoff ✨ on exit you get a permutation, and if you do `B( I ) = A( INDEX( I ) )` for `I=1,N1+N2` then `B` comes out sorted ascending. she did that. 👑

### 🧚 Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

### 🌸 Definition at line 98 of file `dlamrg.f`.

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# 💫 Author 💫

Generated automatically by Doxygen for LAPACK from the source code. (yes the robots wrote the docs, we stan an automated queen 🤖💖)

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<pink>and that's the whole page, bestie!! go merge some sorted lists, you're gonna do amazing 🫶✨</pink>

<purple>LAPACK · Version 3.12.0 · SRC/dlamrg.f(3) — mwah, bye 💋</purple>