Comments on: Advanced MATLAB: Varargin and Nargin- variable inputs to a function

By: Doug

Doug — Fri, 03 Apr 2009 17:39:38 +0000

Seun,

For us to give you some help, you will need to show us what you tried, in code. There are many things that could have been done incorrectly. The data you have shown would plot well.

Doug

By: Seun

Seun — Fri, 03 Apr 2009 17:33:15 +0000

Thanks for your reply, I tried the steps you had in your tutorial, I actually don’t know how to use matlab so I am learning on the go.

I have been able to import the data but when i try to plot the graph i seem to get line graphs which are not correct.

I have posted sample data below so i can explain better what i am trying to plot

I will go over the links you sent again.

Thanks

x-Height
y-Ergo_Index, Ergo_Index_+Sta. Dev., Ergo_Index_-Sta. Dev.
z-Distance

Height Distance Ergo_Index Eg_Index_+SDev. Erg_Index_-SDev.
1 1 8.02810 8.48252 7.57368
1 1 7.23410 7.68852 6.77968
1 1 6.77290 7.22732 6.31848
1 1 7.26650 7.72092 6.81208
1 1 7.85150 8.30592 7.39708
1 1 7.44710 7.90152 6.99268
1 2 6.85090 7.92199 5.77981
1 2 7.54950 8.62059 6.47841
1 2 8.84650 9.91759 7.77541
1 2 7.35340 8.42449 6.28231
1 2 9.51260 10.58369 8.44151
1 2 8.99790 10.06899 7.92681
1 3 7.90830 8.11751 7.69909
1 3 7.92300 8.13221 7.71379
1 3 7.99560 8.20481 7.78639
1 3 8.15680 8.36601 7.94759
1 3 7.87130 8.08051 7.66209
1 3 8.08800 8.29721 7.87879
1 3 8.34180 8.55101 8.13259
1 3 7.64370 7.85291 7.43449
2 1 9.67030 10.07334 9.26726
2 1 8.95520 9.35824 8.55216
2 1 8.68640 9.08944 8.28336
2 1 8.75610 9.15914 8.35306
2 1 8.99480 9.39784 8.59176
2 1 9.44720 9.85024 9.04416
2 1 9.73000 10.13304 9.32696
2 1 9.30680 9.70984 8.90376
2 2 7.59970 7.85001 7.34939
2 2 7.38770 7.63801 7.13739
2 2 7.45730 7.70761 7.20699
2 2 7.86410 8.11441 7.61379
2 2 7.61410 7.86441 7.36379
2 2 7.70390 7.95421 7.45359
2 2 8.15410 8.40441 7.90379
2 2 7.87890 8.12921 7.62859
3 3 7.28780 7.86754 6.70806
3 3 7.57240 8.15214 6.99266
3 3 8.52170 9.10144 7.94196
3 3 7.88650 8.46624 7.30676
3 3 7.39120 7.97094 6.81146
3 3 8.50380 9.08354 7.92406
3 3 8.30720 8.88694 7.72746
3 3 8.81800 9.39774 8.23826

By: Doug

Doug — Fri, 03 Apr 2009 17:12:41 +0000

Seun,

There are a few steps to this process, it is not clear to me what you are having problems with.

1.) Import data from Excel.
http://blogs.mathworks.com/videos/category/excel/

2.) Doing a 3-d bar graph.
http://www.mathworks.com/matlabcentral/fileexchange/23439

3.) Adding more visualization to a standard plot type.
http://www.mathworks.com/access/helpdesk/help/techdoc/creating_plots/f7-20419.html

What have you tried, and specifically where are you stuck?

-Doug

By: Seun

Seun — Fri, 03 Apr 2009 17:04:35 +0000

Hi Doug,

Sorry to trouble you, I am trying to plot a 3axis(XYZ) bar graph with some data I have in excel, would attach the data here but it doesn’t seem possible to.

x-Height
y-Ergo_Index
z-Distance

I also want to plot the mean, standard deviation +/- of the Ergo_Index on the same graph.

Could you point me in the right direction, I am not too good at matlab, I have tried the gui method to do this but never seem to get a suitable graph or one in 3d either.

Thanks

By: Doug

Doug — Wed, 01 Apr 2009 20:48:28 +0000

Siva,

Please post the actual code, the function, and how you call it. You can simplify the function so it is shorter for this purpose.

Doug

By: siva

siva — Tue, 31 Mar 2009 11:06:19 +0000

i have a doubt in using varargin. if i give this as it is in the calling function, i get “Attempted to execute script varargin as a function”. if i omit varargin, it gives the error as “One or more output arguments not assigned during call to…”. what should i have to do? plz send the answer to my mail soon. thanks in advance

By: Jiro

Jiro — Sat, 29 Mar 2008 13:39:32 +0000

dylan,

Make sure you are using (curly) braces and not parentheses:

alpha = varargin{1}

“varargin” is a cell array, so you need to use braces to get the contents of each element. Parentheses will only give you back the element as a cell.

By: dylan

dylan — Sat, 29 Mar 2008 03:27:01 +0000

i followed your code exactly and i get the following error:
>> main(1)
??? Undefined function or method ‘mtimes’ for input arguments of type ‘cell’.

Error in ==> main at 19
out=alpha * beta;

By: Luca Balbi

Luca Balbi — Fri, 11 Jan 2008 06:59:32 +0000

Hello Doug, great work as always!

I think that the recent introduction of the inputParser object has made things evolve a bit with respect to the nargin approach.
Have you ever thought about creating a video with a demo of inputParser?

By: Doug

Doug — Wed, 09 Jan 2008 17:26:48 +0000

Justin,

You can use num2str to make a number into text. You can have a function output be string if that is what you want.

Doug