KURVP1(3NCARG)

💖 NAME 💖

KURVP1 — bestie, this one crunches the numbers that KURVP2 is gonna need later. That's it, that's the job. ✨

Oh and quick thing — this page lives in the NCAR Graphics manual, section 3NCARG, so that's the whole vibe we're working with here. 🎀

✨ SYNOPSIS ✨

CALL KURVP1 (N, X, Y, XP, YP, TEMP, S, SIGMA, IER)

So here's the tea, bestie: this subroutine figures out certain values that KURVP2 then uses to compute an interpolatory spline under tension threading through a sequence of points in the plane that form a closed curve. 🌀

🚨 Real talk though — KURVP1 does NOT do the actual interpolation. The actual computation of the interpolated values must be done using KURVP2. KURVP1 is the prep girlie, KURVP2 is the main character. Periodt. 💅

🌸 DESCRIPTION 🌸

Okay so here's every single thing getting passed in and out, one by one, no skipping, we don't do that here:

• N (integer, input) — how many input data points you've got. Gotta be N > 1, no cap. ✋
• X (real, input) — an array holding the X values of your points. 💫
• Y (real, input) — an array holding the Y values of your points. Heads up bestie: adjacent pairs of points must be distinct. Like, no duplicates sitting next to each other. 🚫
• XP (real, output) — an array of length N. 🫶
• YP (real, output) — an array of length N. 🫶
• TEMP (real, input) — scratch space, bestie. It's the emotional support array. 🧺
• S (real, output) — an array of length N. This is the one you're gonna pass along to KURVP2. 🎁
• SIGMA (real, input) — the tension factor, aka the drama dial 🎚️. Values near zero give you a cubic spline (soft, smooth, gentle). Large values (like, say, 50) give you nearly a polygonal line (stiff, angular, unbothered). A typical value is 1. Iconic default energy. 👑
• IER (integer, output) — the error return value. If IER comes back as 0, congrats babe, no errors were detected. 🎉 Otherwise:
  • = 1 if N is less than 2.
  • = 2 if a pair of adjacent points coincide.

💀 Yeah so those two error codes are your whole "something's off" radar. If you're getting a 1, your N is too smol. If you're getting a 2, you've got two points sitting on top of each other being weird about it.

🔥 ACCESS 🔥

Wanna use KURVP1? Load the NCAR Graphics library ngmath. That's the one. That's the key. 🗝️

🦋 SEE ALSO 🦋

• kurvp2 — the one who actually does the interpolation, the moment you've all been waiting for 💅
• fitgrid_params — the params, the settings, the lore 📜

Also! Full, complete, no-crumbs-left documentation for Fitgrid is living at this URL right here:

http://ngwww.ucar.edu/ngdoc/ng/ngmath/fitgrid/fithome.html

Go read it, it's giving thorough. 📖✨

👑 COPYRIGHT 👑

Copyright (C) 2000 University Corporation for Atmospheric Research

The use of this Software is governed by a License Agreement.

okay that's the whole page bestie, you're officially a KURVP1 girlie now 🎀 go forth and prep those values for KURVP2, you absolute legend 🌈

signing off from the UNIX manual, March 1998 edition — KURVP1(3NCARG), NCAR Graphics, forever and always 💜✨