17.7 LSQ, plotting a linear relation or a curve

A simple program to make and plot a least squares or maximum likelihood relation between

two parameters, plot a curve using the xy parameters or plot a hsitogram using the xy parameters. Input is from a file with two columns x and y. The program also calculates average and standard deviation of the two data sets. If a linear fit is made, the program also makes an output used with GMT in order to make nice plots. The PostScript output file is lsq.eps and the GMT file is lsq_gmt.out. In order to produce the GMT plot (only Unix), use command gmtxy lsq_gmt.out. The curve can be plotted with points only, lines joining the points with points plotted or just lines between points. X and y-axis for the curve plotting can be linear or logaritmic.

For plotting histograms, the input data must be equally spaced in x like e.g.

0 4

10 22

20 11

30 4

40 2

50 0

Examples of plots are found under program GETSTRESSDROP