diff options
Diffstat (limited to 'src/slalib/sun67.htx/node103.html')
| -rw-r--r-- | src/slalib/sun67.htx/node103.html | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/slalib/sun67.htx/node103.html b/src/slalib/sun67.htx/node103.html new file mode 100644 index 0000000..4525328 --- /dev/null +++ b/src/slalib/sun67.htx/node103.html @@ -0,0 +1,170 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<!--Converted with LaTeX2HTML 97.1 (release) (July 13th, 1997) + by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds +* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan +* with significant contributions from: + Jens Lippman, Marek Rouchal, Martin Wilck and others --> +<HTML> +<HEAD> +<TITLE>SLA_FITXY - Fit Linear Model to Two Sets</TITLE> +<META NAME="description" CONTENT="SLA_FITXY - Fit Linear Model to Two Sets"> +<META NAME="keywords" CONTENT="sun67"> +<META NAME="resource-type" CONTENT="document"> +<META NAME="distribution" CONTENT="global"> +<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso_8859_1"> +<LINK REL="STYLESHEET" HREF="sun67.css"> +<LINK REL="next" HREF="node104.html"> +<LINK REL="previous" HREF="node102.html"> +<LINK REL="up" HREF="node13.html"> +<LINK REL="next" HREF="node104.html"> +</HEAD> +<BODY > +<BR> <HR> +<A NAME="tex2html1456" HREF="node104.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html1454" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html1448" HREF="node102.html"> +<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="previous_motif.gif"></A> <A HREF="sun67.html#stardoccontents"><IMG ALIGN="BOTTOM" BORDER="0" + SRC="contents_motif.gif"></A> +<BR> +<B> Next:</B> <A NAME="tex2html1457" HREF="node104.html">SLA_FK425 - FK4 to FK5</A> +<BR> +<B>Up:</B> <A NAME="tex2html1455" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html1449" HREF="node102.html">SLA_EVP - Earth Position & Velocity</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<H2><A NAME="SECTION000490000000000000000"> </A><A NAME="xref_SLA_FITXY"> </A><A NAME="SLA_FITXY"> </A> +<BR> +SLA_FITXY - Fit Linear Model to Two <IMG WIDTH="42" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img20.gif" + ALT="$[\,x,y\,]$"> Sets +</H2> + <DL> +<DT><STRONG>ACTION:</STRONG> +<DD>Fit a linear model to relate two sets of <IMG WIDTH="42" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img20.gif" + ALT="$[\,x,y\,]$"> coordinates. +<DT><STRONG>CALL:</STRONG> +<DD><TT>CALL sla_FITXY (ITYPE,NP,XYE,XYM,COEFFS,J)</TT> +<P> </DL> +<P> <DL> +<DT><STRONG>GIVEN:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>ITYPE</EM></TD> +<TH ALIGN="LEFT"><B>I</B></TH> +<TD ALIGN="LEFT" NOWRAP>type of model: 4 or 6 (note 1)</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>NP</EM></TD> +<TD ALIGN="LEFT"><B>I</B></TD> +<TD ALIGN="LEFT" NOWRAP>number of samples (note 2)</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>XYE</EM></TD> +<TD ALIGN="LEFT"><B>D(2,NP)</B></TD> +<TD ALIGN="LEFT" NOWRAP>expected <IMG WIDTH="42" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img20.gif" + ALT="$[\,x,y\,]$"> for each sample</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>XYM</EM></TD> +<TD ALIGN="LEFT"><B>D(2,NP)</B></TD> +<TD ALIGN="LEFT" NOWRAP>measured <IMG WIDTH="42" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img20.gif" + ALT="$[\,x,y\,]$"> for each sample</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>RETURNED:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>COEFFS</EM></TD> +<TH ALIGN="LEFT"><B>D(6)</B></TH> +<TD ALIGN="LEFT" NOWRAP>coefficients of model (note 3)</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>J</EM></TD> +<TD ALIGN="LEFT"><B>I</B></TD> +<TD ALIGN="LEFT" NOWRAP>status:</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM></EM></TD> +<TD ALIGN="LEFT"><B></B></TD> +<TD ALIGN="LEFT" NOWRAP> 0 = OK</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM></EM></TD> +<TD ALIGN="LEFT"><B></B></TD> +<TD ALIGN="LEFT" NOWRAP> -1 = illegal ITYPE</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM></EM></TD> +<TD ALIGN="LEFT"><B></B></TD> +<TD ALIGN="LEFT" NOWRAP> -2 = insufficient data</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM></EM></TD> +<TD ALIGN="LEFT"><B></B></TD> +<TD ALIGN="LEFT" NOWRAP> -3 = singular solution</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>NOTES:</STRONG> +<DD><DL COMPACT> +<DT>1. +<DD>ITYPE, which must be either 4 or 6, selects the type of model +fitted. Both allowed ITYPE values produce a model COEFFS which +consists of six coefficients, namely the zero points and, for + each of XE and YE, the coefficient of XM and YM. For ITYPE=6, + all six coefficients are independent, modelling squash and shear + as well as origin, scale, and orientation. However, ITYPE=4 + selects the <I>solid body rotation</I> option; the model COEFFS + still consists of the same six coefficients, but now two of + them are used twice (appropriately signed). Origin, scale + and orientation are still modelled, but not squash or shear - + the units of X and Y have to be the same. + <DT>2. +<DD>For NC=4, NP must be at least 2. For NC=6, NP must be at + least 3. + <DT>3. +<DD>The model is returned in the array COEFFS. Naming the + six elements of COEFFS <I>a</I>,<I>b</I>,<I>c</I>,<I>d</I>,<I>e</I> & <I>f</I>, + the model transforms <I>measured</I> coordinates + <IMG WIDTH="63" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img113.gif" + ALT="$[x_{m},y_{m}\,]$"> into <I>expected</I> coordinates + <IMG WIDTH="52" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img114.gif" + ALT="$[x_{e},y_{e}\,]$"> as follows: + <BLOCKQUOTE><I>x</I><SUB><I>e</I></SUB> = <I>a</I> + <I>bx</I><SUB><I>m</I></SUB> + <I>cy</I><SUB><I>m</I></SUB> <BR> + <I>y</I><SUB><I>e</I></SUB> = <I>d</I> + <I>ex</I><SUB><I>m</I></SUB> + <I>fy</I><SUB><I>m</I></SUB></BLOCKQUOTE> + For the <I>solid body rotation</I> option (ITYPE=4), the + magnitudes of <I>b</I> and <I>f</I>, and of <I>c</I> and <I>e</I>, are equal. The + signs of these coefficients depend on whether there is a + sign reversal between [<I>x</I><SUB><I>e</I></SUB>,<I>y</I><SUB><I>e</I></SUB>] and [<I>x</I><SUB><I>m</I></SUB>,<I>y</I><SUB><I>m</I></SUB>]; + fits are performed + with and without a sign reversal and the best one chosen. + <DT>4. +<DD>Error status values J=-1 and -2 leave COEFFS unchanged; + if J=-3 COEFFS may have been changed. + <DT>5. +<DD>See also sla_PXY, sla_INVF, sla_XY2XY, sla_DCMPF. + </DL></DL> +<BR> <HR> +<A NAME="tex2html1456" HREF="node104.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html1454" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html1448" HREF="node102.html"> +<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="previous_motif.gif"></A> <A HREF="sun67.html#stardoccontents"><IMG ALIGN="BOTTOM" BORDER="0" + SRC="contents_motif.gif"></A> +<BR> +<B> Next:</B> <A NAME="tex2html1457" HREF="node104.html">SLA_FK425 - FK4 to FK5</A> +<BR> +<B>Up:</B> <A NAME="tex2html1455" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html1449" HREF="node102.html">SLA_EVP - Earth Position & Velocity</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<ADDRESS> +<I>SLALIB --- Positional Astronomy Library<BR>Starlink User Note 67<BR>P. T. Wallace<BR>12 October 1999<BR>E-mail:ptw@star.rl.ac.uk</I> +</ADDRESS> +</BODY> +</HTML> |