Comments on: Mental Model for feval

By: Matthew Simoneau

Matthew Simoneau — Tue, 30 May 2006 13:40:39 +0000

FYI, the page I linked to above has moved to a new location.

By: Matthew Simoneau

Matthew Simoneau — Mon, 06 Feb 2006 15:32:47 +0000

I’m constantly surprised to find relatively sophisticated MATLAB users who are unfamiliar with this “command/function duality”. A section in the MATLAB documentation describes it clearly, but many people never see it:

By: Ben

Ben — Tue, 31 Jan 2006 19:57:39 +0000

I’ll agree with Per here: I certainly fall victim to “transparency to documentation” occasionally. But sometimes that’s more of a problem with the user (including myself) that MATLAB shouldn’t have to fix; certainly big things like “Notes For C Programmers” are completely necessary and put up appropriately large red flags for common mental model errors when jumping between C and MATLAB.

However an advantage with MATLAB is that you can browse the source of many MATLAB functions to get a direct view (and a good complement to documentation) of what’s going on under the hood, unless they are builtin, like ‘dir’ :-(.

By: loren

loren — Tue, 31 Jan 2006 16:53:06 +0000

Krisna- Welcome to the MATLAB community! I recommend you read Getting Started with MATLAB, run demos, read the Usenet MATLAB newsgroup comp.soft-sys.matlab, and watch this blog for helpful topics.

By: krishna kr tiwari

krishna kr tiwari — Tue, 31 Jan 2006 15:31:28 +0000

I am a post graguate student.Studing in master of eectronics science.I currently worked on MATLAB but nobody know about the MATLAB.So please you give me a proper guiedens.

krisna kr tiwari
IPS ACADEMY.Indore(M.P.)
INDIA

By: per isakson

per isakson — Thu, 26 Jan 2006 15:13:55 +0000

RTFM. The problem (to some of us) is that we already have mental models of *commands* like DIR, SAVE, and PRINT when we try Matlab for the first time. Our models work well with Matlab when we start using it *interactively*. Our models are so well established that *looking through* the documentation of the commands does not change our models.

To me a problem with the Matlab documentation is that I tend to overlook powerful (added) features of functions because they are “hidden” in the body text of the descriptions and not addressed by the examples.

By: loren

loren — Mon, 16 Jan 2006 12:31:18 +0000

Is the doc for dir not clear perhaps? You can get this structure of output by using dir directly also: fstr = dir('*.gif') in the help description it says:

files = dir('directory') returns the list of files in the specified directory (or the current directory, if dirname is not specified) to an m-by-1 structure with the fields: name, date, bytes, isdir.

By: Yang

Yang — Sun, 15 Jan 2006 07:27:44 +0000

Yeah, I think the benefit of usage of the “feval” function is to return a structure argument like the ways described in “More on eval”.

By: per isakson

per isakson — Fri, 13 Jan 2006 14:48:55 +0000

Functions, which take strings as input arguments, may be used in command form. Some of these are know as commands in other environments, e.g. DIR in DOS. DIR in Matlab thus becomes not as a Matlab function, but rather a shortcut to DIR of the underlying OS. It is possible to overlook that in Matlab the function form is valid for DIR. The command form doesn’t return an argument. Thus, you can see contructs like “files = feval(’dir’,'*.gif’);” and “files = evalc( ‘dir *.gif’ );”

/ per