Help for IBISLSQ

PURPOSE

   "ibislsq" performs least squares fits on data in an IBIS interface
(tabular) file.  The solutions and/or residuals can be placed in 
specified columns of the file.  The solutions can also be output
to the terminal.  Multiple fits can be done on different parts of
one file.


EXECUTION

     ibislsq INP=DATA.INT  INDCOL=(1,2,3) DEPCOL=(4,5) CONCOL=7  	     SOLCOL=(10,11) RESCOL=(8,9)  'NOPRINT

    This example shows the use of all of the parameters.  The input
file, DATA.INT, is an IBIS interface file.  The data for the independent
variables are in columns (1,2,3), and the data for the dependent 
variables are in columns (4,5).  The control column is used for
multiple fits to be done in one run.  The least square fits are done 
on sets of rows; a new set is started whenever the value in the control 
column changes.  If no control column is specified then one fit
is done on the whole file.  The SOLCOL and RESCOL parameters specify
in which columns, of the input file, the results will be put.  If either
or both are not specified then they will not be output.  There must be
as many solution columns and residual columns as there are dependent 
columns.  The data in the residual columns correspond one-to-one with
the data in the dependent columns.  The solution is put out in the
first N rows of the SOLCOL columns, where N is the number of independent
columns; the rest of the rows in the set are filled with zeros.   Normally
the solution for each set is printed to the terminal, but this can 
be turned off with the 'NOPRINT keyword.

    The length of each set should, of course, be longer than the
number of independent variables (columns).  If it is not then the
least squares fit will not be called and values of -999.0 will be
put out for the solution.  If some columns of the independent data
are dependent then the error MATRIX RANK TOO SMALL be be printed,
and -999.0's will be put out for the solution.  If there is no
solution then zeros will be put out for the residuals.



EXAMPLES

   Suppose that columns 1 and 2 contain points (x,y) in a plane 
   and  column  7 contains a function  f(x,y).   The  following 
   sequence  will perform a quadratic least squares fit  h(x,y) 
   and place the residuals in column 8.

   mf INP=A FUNCTION=("C3=C1*C1","C4=C2*C2","C5=C1*C2","C6=1")
   ibislsq INP=A INDCOL=(1,2,3,4,5,6) DEPCOL=7 RESCOL=8


RESTRICTIONS

The maximum number of independent columns (variables) is 20.
The maximum number of dependent columns (variables) is 5.
The maximum length of any set is 5000.
The maximum column length of the file is 10000.
Interface files are assumed to have 40 or less columns.



WRITTEN BY:            K. F. Evans	April 1986

COGNIZANT PROGRAMMER:  K. F. Evans

REVISION:  A. Scop (CRI) 2 Jan. 1995  Made portable for UNIX