TEND-BFIT(1)

✨ tend-bfit — the b-value curve glow-up ✨

okay bestie, so this is tend-bfit, a little helper hanging out under the tend umbrella, and it does non-linear least-squares fitting of b-value curves. that's the whole vibe. 💖

🌸 SYNOPSIS 🌸

tend bfit [@file ...]  [-i <nin>] -b <b1 b2 ...> [-w <w1 w2 ...>] [-imax
<# iter>] [-eps <epsilon>] [-o <nout>]

like. she's got a shape. respect it. 💅

🦋 DESCRIPTION 🦋

okay so picture this: you've got DWI values chillin' along axis 0 of your input, and every one of them corresponds to a different b value. what tend-bfit does is non-linear least-squares fitting of b-value curves, and it replaces axis 0 with three values:

• amp
• dec
• err

those three come out of a non-linear least-squares fit of amp*exp(-b*dec) to the range of DWI values along input axis 0, treated as a function of the changing b values. so like, the whole curve gets squished into three lil numbers. iconic behavior, honestly. 🎀

💅 OPTIONS 💅

• @file ... — response file(s) containing command-line arguments. yes she can read a whole file of args, we love a delegation queen. 📄
• -i <nin> — input nrrd. the list of DWIs from different b-values has to be along axis 0, no exceptions bestie. default: -
• -b <b1 b2 ...> — the b values across axis 0 of the input nrrd. 2 or more doubles, okay? this one's required, not optional, she's the main character. 🔥
• -w <w1 w2 ...> — weights for the samples in the non-linear fitting. 2 or more doubles.
• -imax <# iter> — max number of iterations to use in the non-linear fitting. orrrr you can pass 0 to do only the initial linear fit (int). default: 10
• -eps <epsilon> — epsilon convergence threshold for the non-linear fitting (double). default: 1
• -o <nout> — output tensor volume (string). default: -

ngl, that -b is not playing around — she's mandatory and she needs at least two values. don't come at her with one b value and expect magic. 💀

👑 SEE ALSO 👑

• tend(1) — the whole fam, go say hi. 🫶

k that's the whole page bestie, no cap. this was tend-bfit(1) from the User Commands manual, all the way back in April 2021 — vintage but still slaying. go fit some curves, drink water, and remember: axis 0 or it didn't happen. mwah 💖✨