CSA2XS(3NCARG)

✨ CSA2XS ✨

okay bestie, gather round, because we're doing CSA2XS from the NCAR GRAPHICS manual (it's a 3NCARG page, iykyk) and it's literally the ✨expanded✨ version — cubic spline approximation, two-dimensional input, gridded output. she does a lil bit of everything and she's not sorry 💅

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🌸 NAME 🌸

CSA2XS — cubic spline approximation, expanded entry for two-dimensional input, gridded output. no cap, that's the whole vibe. 🦋

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🎀 SYNOPSIS 🎀

CALL CSA2XS (NI, XI, UI, WTS, KNOTS, SMTH, DERIV, NXO, NYO, XO, YO, UO,
NWRK, WORK, IER)

that's a LOT of arguments and honestly? she ate. 👑

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💖 DESCRIPTION 💖

okay so here's the full rundown of every single thing you're passing in, 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, more than three, but maybe more-more, depending. 🙈
• XI — (real, input) an array holding the X - Y coordinates of the input data points. XI is dimensioned for 2 x NI. XI(1,L) is the X coordinate and XI(2,L) is the Y coordinate for the input domain, for L=1,NI. she's two rows, bestie, don't fight it. 🧚
• 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 the coordinate (XI(1,L),XI(2,L)) for L=1,NI. 💜
• WTS — (real, input) an array dimensioned for NI containing weights for the UI values at the input XI values, that is, WTS(L) is a weight for the value of UI(L) for L=1,NI. if you do not desire to weight the input UI values, then set WTS(1) to -1. the weights in the WTS array are relative and may be set to any non-negative value. when CSA2XS is called, the weights are summed and the individual weights are normalized so that the weight sum is unity. so she does the math for you, iconic behavior honestly. ⭐
• KNOTS — (integer, input) the number of knots to be used in constructing the approximation spline. KNOTS is dimensioned for 2 and provides the number of knots to be used in the X and the Y directions. both KNOTS(1) and KNOTS(2) must be at least 4. the larger the values for KNOTS, the closer the approximated curve will come to passing through the input function values. more knots = more clingy, choose wisely 🎀
• SMTH — (real, input) a parameter that controls extrapolation into data sparse regions. if SMTH is zero, then nothing special is done in data sparse regions. a good first choice for SMTH is 1. she's giving ✨data sparse region management✨
• NDERIV — (integer, input) an array dimensioned for 2 that specifies, for each coordinate, whether you want functional values (=0), first derivative values (=1), or second derivative values (=2). pick your fighter 🥊
• 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. 🌈
• 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. 🦋
• UO — (real, output) an array dimensioned for NXO x NYO containing the calculated function values for the output surface. UO(I,J) is the calculated functional value at (XO(I),YO(J)) for I=1,NXO and J=1,NYO. this is the one you actually came for, the main character of the argument list 👑
• NWRK — (integer, input) the size of the WORK array. NWRK must be at least KNOTS(1)*KNOTS(2)*(KNOTS(1)*KNOTS(2)+3). yes that's a real formula, yes you have to actually compute it, no she will not do it for you 😭
• WORK — (real, input) a work array dimensioned for NWRK. it's the little helper. the emotional support array. 🫶
• 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. check her, always check her 💀

bestie heads up: IER non-zero means something went sideways and you gotta go read csagrid_errors. don't ignore it. that's not the vibe.

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🔥 USAGE 🔥

CSA2XS is called to find an approximating cubic spline for two-dimensional input data. CSA2XS is called if you want to weight the input data values, calculate derivatives, or handle data sparse areas specially.

if you do not want to do any of these three things, then use CSA2S.

that's it. that's the whole test. three yeses → you're here. zero yeses → go hang out with CSA2S instead. lowkey efficient of them. ✨

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💅 ACCESS 💅

to use CSA2XS, load the NCAR Graphics library ngmath. that's the whole access situation, no gatekeeping, just ngmath. 🌸

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👑 SEE ALSO 👑

• csagrid
• csa2s
• csa2ls
• csa2lxs

complete documentation for Csagrid is available at URL

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

go read it, she's thorough 🧚

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🍓 COPYRIGHT 🍓

Copyright (C) 2000 University Corporation for Atmospheric Research

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

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okay that's the whole page bestie!! 💖 this was the CSA2XS entry from the NCAR GRAPHICS manual, CSA2XS(3NCARG), and it's dated January 1999 — yes she's an elder icon and she still serves 👑✨ go forth and spline responsibly, and remember: check your IER, size your NWRK, and hydrate. periodt 💅🌸