slaPxy -

SYNOPSYS

PARAMETERS

int np

double ( *xye

DESCRIPTION

  Given arrays of "expected" and "measured" [x,y] coordinates, and a
  linear model relating them (as produced by slaFitxy), compute
  the array of "predicted" coordinates and the rms residuals.

Given

     np      int            number of samples
     xye     double[np]     expected [x,y] for each sample
     xym     double[np]     measured [x,y] for each sample
     coeffs  double[6]      coefficients of model (see below)

Returned

     xyp     double[np]     predicted [x,y] for each sample
     *xrms   double         RMS in x
     *yrms   double         RMS in y
     *rrms   double         total RMS (vector sum of xrms and yrms)

  The model is supplied in the array coeffs.  Naming the

elements of coeff as follows

     coeffs[0] = a
     coeffs[1] = b
     coeffs[2] = c
     coeffs[3] = d
     coeffs[4] = e
     coeffs[5] = 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 slaFitxy, slaInvf, slaXy2xy, slaDcmpf

Called

 slaXy2xy

  P.T.Wallace   Starlink   31 October 1993

SEE ALSO

• slalib.3