CURVD(3NCARG)

✨ CURVD ✨

okay bestie, welcome to the NCAR Graphics corner of the universe 💖 this lil page is all about CURVD, a Fortran function that gives you derivatives for 1D functions. no cap, that's the whole vibe.

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🌸 NAME 🌸

CURVD — derivatives for 1D functions. that's it, that's the girl 💅

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🦋 SYNOPSIS 🦋

FUNCTION CURVD (T, N, X, Y, YP, SIGMA)

so this function calculates a derivative at a specified point using a spline under tension. and listen — CURV1 must be called prior to calling CURVD, and the values thus obtained used as input to CURVD. the derivative value is what gets returned. periodt ✨

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🎀 DESCRIPTION 🎀

here's the whole cast of characters, one by one, no skips:

• T — (real, input) the abscissa for which an interpolated function value is desired. yes she wants the value, she's asking nicely 🥺
• N — (integer, input) the number of input data values. heads up: (N > 1) — you need more than one, bestie, that's the rule 🙈
• X — (real, input) an array containing the abscissae for the input function.
• Y — (real, input) an array containing the functional values of the input data — Y(K) is the functional value at X(K) for K=1,N. iconic indexing behavior, we love a clean mapping 💖
• YP — (real, input) contains values for the second derivative (as calculated by CURV1). so like, CURV1 did the homework, you're just handing it in 🫶
• SIGMA — (real, input) tension factor. okay this one is important:
  • values near zero result in a cubic spline 🌈
  • large values (e.g. 50) result in nearly a polygonal line — she's stiff, she's angular, she's not curving for anyone
  • a typical value is 1

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👑 RETURN VALUE 👑

CURVD returns the derivative value of the interpolated curve at the specified point T. that's the whole bag, that's the main character moment 🔥

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💜 ACCESS 💜

to use CURVD, load the NCAR Graphics library ngmath. link her in or she simply will not show up, fr fr 💀

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🌟 SEE ALSO 🌟

• curv1
• fitgrid_params

complete documentation for Fitgrid is available at URL http://ngwww.ucar.edu/ngdoc/ng/ngmath/fitgrid/fithome.html — go read, it's giving resourceful 🧚

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🍓 COPYRIGHT 🍓

Copyright (C) 2000
University Corporation for Atmospheric Research

the use of this Software is governed by a License Agreement. read it, respect it, it's the law bestie ⭐

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tiny reminder from your girl: call CURV1 first. CURVD does not do that part for you and it will simply not have the YP values it needs. that's not a vibe, that's a bug in your code 🙈

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and that's the whole page, babe!! this was the CURVD entry in the NCAR Graphics manual, from the UNIX crew, dated March 1998, and the title page read CURVD(3NCARG) — mwah, go compute some derivatives, you absolute legend 💅💖✨