---
name: "linfit"
section: "3m"
platform: "linux"
package: "iraf"
version: "2.11.3-2"
release: "Debian 3.0 (Woody)"
platforms: ["linux"]
url: "https://new.carta.tech/linfit"
---

# linfit(3m)

## NAME

linfit

## DESCRIPTION

subroutine linfit.f

source\
   Bevington, pages 104-105.

purpose\
   make least-squares fit to a data set with a straight line

usage\
   call linfit (x, y, sigmay, npts, mode, a, sigmaa,\
     b, sigmab, r)

description of parameters\
   x      - array of data points for independent variable\
   y      - array of data points for dependent variable\
   sigmay - array of standard deviations for y data points\
   npts   - number of pairs of data points\
   mode   - determines method of weighting least-squares fit\
            \+1 (instrumental) weight(i) = 1./sigmay(i)\*\*2\
             0 (no weighting) weight(i) = 1.\
            \-1 (statistical)  weight(i) = 1./y(i)\
   a      - y intercept of fitted straight line\
   sigmaa - standard deviation of a\
   b      - slope of fitted straight line\
   sigmab - standard deviation of b\
   r      - linear correlation coefficient

subroutines and function subprograms required\
   none