STAR_FUN

Name

star_fun

Purpose

Single 2-d gaussian image, support routine for STARFIT.

Description

Evaluate the sum of one 2-d guassian and a 2-d 2nd order polynomial
and optionally return the value of it's partial derivatives.
Evaluate the equation y=f(i) where:
X = I MOD NX
Y = I / NX
R = SQRT( (X-A0)^2 + (Y-A1)^2 )
Z = R/A3
F(I) = A2*EXP(-Z1^2/2) + A4
Function parameters
--------------------------------------------
A0 = X location of center of Pluto,
A1 = Y location of center of Pluto,
A2 = height of gaussian for Pluto,
A3 = the 1/e width of the guassian,
A4 = Constant term for the background,

Calling Sequence

STARFIT_FUN,I,A,F[,PDER]

Inputs

I = Independent variable, actually, just an index into 2-d array.
A = Parameters of equation described above.
OPTIONAL KEYWORD PARAMETERS:
XSIZE = width of image

Outputs

F = value of function at each F(I).

Optional Output Parameters

PDER = (N_ELEMENTS(I),9) array containing the
partial derivatives. P(I,J) = Derivative
at Ith point w/respect to Jth parameter.

Common Blocks

starfit_com - contains the x-width of the array stored in A

Side Effects

NONE.

Restrictions