lis_array_mgs(3f)

💖 lis_array_mgs — bestie edition 💖

okay so you're here for lis_array_mgs, one of the Lis Library Functions (that's the (3f) manual, section 3f, we love her). She does one thing and she does it flawlessly: QR factorization, but make it modified Gram-Schmidt. no cap.

✨ SYNOPSIS ✨

subroutine lis_array_mgs(LIS_INTEGER n, LIS_SCALAR a(), LIS_SCALAR q(),
LIS_SCALAR r(), LIS_INTEGER ierr);

look at her. five arguments, zero drama. 🎀

🦋 DESCRIPTION 🦋

So here's the tea: this routine calculates the QR factorization

QR=A

using the modified Gram-Schmidt process. that's it. that's the whole vibe. she takes your matrix A, and she hands you back a Q and an R that multiply back into A. iconic behavior honestly. 💅

🌸 INPUT 🌸

• n — the size of the matrices. she needs to know how big we're going, bestie, and she needs it in LIS_INTEGER form.
• a — the array that stores matrix A, sized n * n. this is your input, your main character, the one you're decomposing.

🎀 OUTPUT 🎀

• q — the array that stores matrix Q, sized n * n. she writes it, you don't have to.
• r — the array that stores matrix R, sized n * n. same deal. Q and R, both freshly served. ✨

heads up: q and r are outputs, so don't come crying to me if whatever was in those arrays before is gone forever. that's just how output arrays work, periodt. 💀

👑 SEE ALSO 👑

• lis(3)
• http://www.ssisc.org/lis/ — the whole Lis universe lives here, go explore 🫶

that's the whole page bestie, go factor something. 💖✨

mwah — this one's from the Lis Library Functions, documented as a man page, dated 3 Dec 2014. it's giving vintage but she still slays. 🦋🌸