fprintfEmpty

Psychtoolbox › PsychMatlabTests

Mathworks Case ID: 297266, reported 10/3/99.

FPRINTF terminates when it gets an empty matrix [].

dear mathworks

i was very surprised to discover a bug in FPRINTF today:

x=1;
y=1;
fprintf('x %d y %d\n',x,y);
PRODUCES THIS EXPECTED OUTPUT:
x 1 y 1

x=[];
y=1;
fprintf('x %d y %d\n',x,y);
PRODUCES THIS UNEXPECTED OUTPUT:
x
WHEREAS I EXPECTED THIS OUTPUT:
x [] y 1

when the variable's value is the empty matrix, FPRINTF terminates the
printout prematurely, suppressing the rest of it. The FPRINTF
documentation provided by HELP and DOC says nothing of this awkward
behavior. I expected FPRINTF to print the Matlab symbol for empty matrix,
"[]".

Using the empty matrix to represent missing values is one of the great
features of Matlab. Having FPRINTF abort the rest of the print out, and
my data, is contrary to the whole spirit of coping gracefully with
missing values.

I suspect that this bug is platform-independent. I'm running Matlab 5.2.1
on a PowerMac. I know that MathWorks has no current plans to upgrade the
OS9 version, but I understand that it is still logging bugs, to keep its
options open.

denis pelli
professor of psychology and neural science at nyu
apple developer

Reported as a bug to Mathworks on 10/3/99, Case ID: 297266. Their reply (10/4) follows:

"The behavior you reported is caused by a bug which has been forwarded to
development for cosideration in a future release of Matlab."

Kelly Bletsis
Technical Support Engineer
kbletsis@mathworks.com


Denis Pelli