Weighted Linear Least Squares - Revision history

Mjeppesen at 06:18, 20 January 2022

2022-01-20T06:18:36Z

← Older revision		Revision as of 06:18, 20 January 2022
Line 47:		Line 47:
	1.909741152913573492e+00 * x + 1.434756878848905348e+00 with lines'''		1.909741152913573492e+00 * x + 1.434756878848905348e+00 with lines'''

	~~[[category:Protocols]]~~
	~~[[category:Metabolomics]]~~
	[[category:Data_Processing_and_Analysis]]		[[category:Data_Processing_and_Analysis]]

Mjeppesen: Added to Category

2021-09-11T03:59:44Z

Added to Category

← Older revision		Revision as of 03:59, 11 September 2021
Line 48:		Line 48:

	[[category:Protocols]]		[[category:Protocols]]
			[[category:Metabolomics]]
			[[category:Data_Processing_and_Analysis]]

Wiki Administrator at 04:05, 4 August 2012

2012-08-04T04:05:04Z

← Older revision		Revision as of 04:05, 4 August 2012
Line 46:		Line 46:
	"" using 1:5 with points,		"" using 1:5 with points,
	1.909741152913573492e+00 * x + 1.434756878848905348e+00 with lines'''		1.909741152913573492e+00 * x + 1.434756878848905348e+00 with lines'''

			[[category:Protocols]]

MediaWiki default at 16:15, 23 April 2012

2012-04-23T16:15:16Z

← Older revision		Revision as of 16:15, 23 April 2012
Line 1:		Line 1:
	This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data.		This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data.

	[[File:wlls-example.png\|thumb\|~~200px~~\|Example output plot of weighted linear least squares fit to data performed by '''wlls''']]		[[File:wlls-example.png\|thumb\|300px\|Example output plot of weighted linear least squares fit to data performed by '''wlls''']]

	== Export the data into a text file ==		== Export the data into a text file ==

MediaWiki default at 16:14, 23 April 2012

2012-04-23T16:14:48Z

← Older revision		Revision as of 16:14, 23 April 2012
Line 1:		Line 1:
	This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data.		This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data.

	[[File:wlls-example.png\|~~frame~~\|200px\|Example output plot of weighted linear least squares fit to data performed by '''wlls''']]		[[File:wlls-example.png\|thumb\|200px\|Example output plot of weighted linear least squares fit to data performed by '''wlls''']]

	== Export the data into a text file ==		== Export the data into a text file ==

MediaWiki default at 16:13, 23 April 2012

2012-04-23T16:13:06Z

← Older revision		Revision as of 16:13, 23 April 2012
Line 1:		Line 1:
	This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data.		This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data.

	[[File:wlls-example.png\|frame\|Example output plot of weighted linear least squares fit to data performed by '''wlls''']]		[[File:wlls-example.png\|frame\|200px\|Example output plot of weighted linear least squares fit to data performed by '''wlls''']]

	== Export the data into a text file ==		== Export the data into a text file ==

MediaWiki default: Created page with "This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data. [[File:wlls-example.png|..."

2012-04-23T16:12:19Z

Created page with "This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data. [[File:wlls-example.png|..."

New page

This page details how to use the '''wlls''' program to calculate variance-weighted linear least squares regression parameters from experimental data.

[[File:wlls-example.png|frame|Example output plot of weighted linear least squares fit to data performed by '''wlls''']]

== Export the data into a text file ==
'''wlls''' is picky when it comes to input file formatting. Make sure to follow these instructions to the letter. In short, the input format for '''wlls''' is ASCII text, with a single space separating each field. The first column (field) corresponds to the x-axis data, which is assumed to be known with zero error. All remaining columns are y-axis data values. The number of y-axis values does not have to match for each x-axis point (i.e. the number of fields/columns per row does not have to be constant).

=== Exporting from Excel ===
Say you have a (gasp!) spreadsheet containing the values you need to fit. The file [[File:wlls-example.xlsx]] shows an example dataset. Notice that the '''values are left-justified!!''' This is very important.

You can simply save the excel data as '''Text (Tab Delimited) *.txt'''. Once the file is saved, convert all tabs to spaces with the following linux command:

sed -e 's,\t, ,g' -i wlls-example.txt

Where ''wlls-example.txt'' is the text filename saved from excel. It should look similar to the following data: (Example final text file at [[File:wlls-example.txt]])

10 22 23 21 20 20
20 43 45 38 35 40 41
40 80 82 86 70
50 110 100 95 98 102
80 180 120 240
100 250 300 280 320

== Running the program ==
To run '''wlls''', just execute the following linux command on the cluster:

wlls < wlls-example.txt

Where, again, ''wlls-example.txt'' is the exported, fixed text file you want to fit a line to. The program will respond with output akin to this if everything worked:

[ y = ax + b ]
a = 1.909741152913573492e+00
b = 1.434756878848905348e+00
r2 = 0.998381952730418742

And there you have it!

== Plotting the output ==
If you want to look at the fit line in the context of the data points, you can use '''gnuplot''' as follows:

'''/usr/bin/gnuplot'''
gnuplot> '''unset key'''
gnuplot> '''plot "wlls-example.txt" using 1:2 with points,
"" using 1:3 with points,
"" using 1:4 with points,
"" using 1:5 with points,
1.909741152913573492e+00 * x + 1.434756878848905348e+00 with lines'''