CSA3S(3NCARG)

💖 CSA3S — cubic spline approximation, the simple lil' entry for three-dimensional input 💖

ok so this is CSA3S(3NCARG), one of the NCAR Graphics girlies, and she's here to do cubic spline approximation when you've got 3D input data. no cap. bestie, sit down, we're doing FORTRAN and we're doing it cutely. 🎀

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✨ NAME ✨

CSA3S — cubic spline approximation, simple entry for three-dimensional input 🦋

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✨ SYNOPSIS ✨

CALL CSA3S (NI, XI, UI, KNOTS, NXO, NYO, NZO, XO, YO, ZO,
            UO, NWRK, WORK, IER)

that's the whole vibe. one call, fourteen arguments, slay. 💅

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✨ DESCRIPTION ✨

okay so here's the tea on every single argument, and yes we're doing all of them, no skipping, periodt. 🌸

• NI (integer, input) — the number of input data points. it must be that NI .gt. 3 and, depending on the size of KNOTS below, NI may have to be larger. so like, three ain't it, and sometimes more than four is the move either. 😭
• XI (real, input) — an array holding the X - Y - Z coordinates of the input data points. XI is dimensioned for 3 x NI. XI(1,L) is the X coordinate, XI(2,L) is the Y coordinate, and XI(2,L) is the Z coordinate for the input domain for L=1,NI. (yes, we're reading that exactly as written, no notes, moving on 🙈)
• UI (real, input) — an array dimensioned for NI containing function values at the input XI values, that is, UI(L) is the value of the input function at XI(L) for L=1,NI. the glow-up numbers, basically. ✨
• KNOTS (integer, input) — an array dimensioned for 3 containing the number of knots to be used in each coordinate direction for constructing the approximation spline. KNOTS(I) must be at least 4 for I=1,3. and the tea is: the larger the value for KNOTS, the closer the approximated curve will come to passing through the input function values. more knots = more obsessed with your data points. 🔥
• NXO (integer, input) — the number of X coordinate values in the output grid.
• NYO (integer, input) — the number of Y coordinate values in the output grid.
• NZO (integer, input) — the number of Z coordinate values in the output grid.

(three little counts, one per axis, they're a trio, main character energy 👑)

• XO (real, input) — an array dimensioned for NXO containing the X coordinates of the output surface.
• YO (real, input) — an array dimensioned for NYO containing the Y coordinates of the output surface.
• ZO (real, input) — an array dimensioned for NZO containing the Y coordinates of the output surface.

(yep, "Y coordinates", copy-pasted energy straight from the source, we keep the lore intact 🫶)

• UO (real, output) — an array dimensioned for NXO x NYO x NZO containing the calculated function values for the output function. UO(I,J,K) is the calculated functional value at (XO(I), YO(J), ZO(K)) for I=1,NXO and J=1,NYO and K=1,NZO. this is the moment. this is what you came for. 💖
• NWRK (integer, input) — the size of the WORK array. NWRK must be at least NK * (NK+3) where NK = KNOTS(1) * KNOTS(2) * KNOTS(3). do the math bestie, do not skimp. 🧚
• WORK (real, input) — a work array dimensioned for NWRK. it's just vibing in the background, doing the heavy lifting, not getting any credit. iconic behaviour honestly.
• IER (integer, output) — an error return value. if IER is returned as 0, then no errors were detected. if IER is non-zero, then refer to the man page for csagrid_errors for details. so like, 0 = we ate, non-zero = go read the other page. 💀

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✨ USAGE ✨

CSA3S is called to find an approximating cubic spline for three-dimensional input data.

and the plot twist: if you want to weight the input data values, calculate derivatives, or handle data sparse areas specially, then you will need to use CSA3S. 👀

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✨ ACCESS ✨

to use CSA3XS, load the NCAR Graphics library ngmath. that's it, that's the whole step, go off. 🌈

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✨ SEE ALSO ✨

• csagrid
• csa3xs
• csa3ls
• csa3lxs

complete documentation for Csagrid is available at URL

http://ngwww.ucar.edu/ngdoc/ng/ngmath/csagrid/csahome.html

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✨ COPYRIGHT ✨

Copyright (C) 2000 University Corporation for Atmospheric Research

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

legal bestie has entered the chat. read the license, respect the license, it's giving responsibility. 📜

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and that's the whole page, bestie!! this was the UNIX version from January 1999, filed under CSA3S(3NCARG), brought to you by NCAR Graphics. mwah. 💅💖✨