lis_esolve...sidualnorms(3f)

💖 lis_esolver_get_residualnorms 💖

okay bestie, so this one lives in the Lis Library Functions manual (section 3f, Fortran girlies rise up 🫶), and it's literally the glow-up report card for your eigenpairs. no cap.

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✨ NAME ✨

lis_esolver_get_residualnorms — get the relative residual norms for all the eigenpairs from the eigensolver 💅

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✨ SYNOPSIS ✨

subroutine lis_esolver_get_residualnorms(LIS_ESOLVER esolver, LIS_VECTOR v, LIS_INTEGER ierr);

like. that's it. that's the whole vibe. three args, one icon. 👑

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✨ DESCRIPTION ✨

So what this baddie does is get the relative residual norms

||lx - Ax||_2/||lx||_2

for all the eigenpairs from the eigensolver. every single one. it's giving "we don't leave any eigenpair behind" energy fr fr 🌸

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✨ INPUT ✨

• esolver — the eigensolver 🧚 the main character of this whole operation, lowkey.

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✨ OUTPUT ✨

• v — the vector which stores the residual norms ✨ it's the container, the vessel, the keeper of the receipts. every residual norm gets a little seat in here.

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heads up bestie: v is where the numbers land, so don't come for it expecting anything else. it stores the residual norms, periodt. 💀

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✨ SEE ALSO ✨

• lis(3)
• http://www.ssisc.org/lis/ 🌈

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and that's the whole page, bestie!! this slice of perfection is dated 28 Aug 2014, and it's page lis_esolve...sidualnorms(3f) of the Lis Library Functions manual — go off, queen. mwah. 💅🎀💖