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.help pxy Jun99 "Slalib Package"
.nf
SUBROUTINE slPXY (NP,XYE,XYM,COEFFS,XYP,XRMS,YRMS,RRMS)
- - - -
P X Y
- - - -
Given arrays of "expected" and "measured" [X,Y] coordinates, and a
linear model relating them (as produced by slFTXY), compute
the array of "predicted" coordinates and the RMS residuals.
Given:
NP i number of samples
XYE d(2,np) expected [X,Y] for each sample
XYM d(2,np) measured [X,Y] for each sample
COEFFS d(6) coefficients of model (see below)
Returned:
XYP d(2,np) predicted [X,Y] for each sample
XRMS d RMS in X
YRMS d RMS in Y
RRMS d total RMS (vector sum of XRMS and YRMS)
The model is supplied in the array COEFFS. Naming the
elements of COEFF as follows:
COEFFS(1) = A
COEFFS(2) = B
COEFFS(3) = C
COEFFS(4) = D
COEFFS(5) = E
COEFFS(6) = F
the model is applied thus:
XP = A + B*XM + C*YM
YP = D + E*XM + F*YM
The residuals are (XP-XE) and (YP-YE).
If NP is less than or equal to zero, no coordinates are
transformed, and the RMS residuals are all zero.
See also slFTXY, slINVF, slXYXY, slDCMF
Called: slXYXY
P.T.Wallace Starlink 22 May 1996
Copyright (C) 1996 Rutherford Appleton Laboratory
Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
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.endhelp
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