Routines (alphabetical) > Routines: F > FUNCT

# FUNCT

The FUNCT procedure evaluates the sum of a Gaussian and a 2nd-order polynomial and optionally returns the value of its partial derivatives. Normally, this function is used by CURVEFIT to fit the sum of a line and a varying background to actual data.

This routine is written in the IDL language. Its source code can be found in the file `funct.pro` in the `lib` subdirectory of the IDL distribution.

## Syntax

FUNCT, X, A, F [, Pder]

## Arguments

### X

A vector of values for the independent variable.

### A

A vector of coefficients for the equations:

### F

A named variable that will contain the value of the function at each Xi.

### Pder

A named variable that will contain an array of the size (N_ELEMENTS(X),6) that contains the partial derivatives. Pder(i,j) represents the derivative at the ith point with respect to jth parameter.

## Version History

4.0 | Introduced

## See Also

CURVEFIT