MATLAB Answers

Yanai
5

bug in matlab 2010b, trig functions (cosd, sind etc.)

Asked by Yanai
on 27 Mar 2011
results are not consistent:
cosd(zeros(1,10))
ans =
0 1 1 1 1 1 1 1 1 1

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11 Answers

Answer by David Collins on 20 Apr 2012

Clearing background variables seems to do the trick (R2010b. OS Win7 x64.)
>> sind(22)
ans =
-0.9272
>> clear all
>> sind(22)
ans =
0.3746

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Answer by the cyclist
on 27 Mar 2011

That is not the result I get, but I am using 64-bit 2010b on a Mac, so maybe that explains the difference. I would contact support about this.

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Answer by jiro
on 27 Mar 2011

What's your OS and machine type? I'm on 32-bit 2010b on Win7, and I get the correct result (different from yours). Just to make sure, what do you get when you type
which cosd
which zeros
Do you get the correct answer when you do this?
cos(zeros(1,10))

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I use:
MATLAB Version 7.11.0.584 (R2010b)
Operating System: Microsoft Windows 7 Version 6.1 (Build 7600)
Java VM Version: Java 1.6.0_17-b04 with Sun Microsystems Inc. Java HotSpot(TM) 64-Bit Server VM mixed mode
cos(zeros(1,10)) return the right answer
built-in (C:\Program Files\MATLAB\R2010b\toolbox\matlab\elmat\zeros)
built-in (C:\Program Files\MATLAB\R2010b\toolbox\matlab\elfun\@double\cosd) % double method
and just to clarify, sind & tand have the same problem
jiro
on 27 Mar 2011
I agree with the cyclist and, I suggest contacting tech support:
http://www.mathworks.com/support/

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Answer by Alan Jennings on 1 Apr 2011

This happens to me to. Same built in function, operating system and Java. Took me a while to figure out why my results weren't lining up; especially since it works right for some values. Amost seems like it does sind() on the first one sometimes.
Didn't see anything in bug reports, so I'll put one in... Till then, I'll just use cos(deg2rad()). Seems to work. Actually, I'll do the conversion myself, since I'm still getting screwy results, sometimes.

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Answer by Alan Jennings on 2 Apr 2011

Checked it out on another Windows 7 system, identical version, operating system and Java information as above, and cosd works fine. So there must be something else than just that.

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Answer by Alan Jennings on 5 Apr 2011

Just tried it on the first machine again, and works fine. Maybe some delayed windows update? No idea.

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Answer by MXM
on 7 Apr 2011

Exactly the same problem occurs here (intermittently).
Version 7.11.0.584 (R2010b), 64-bit on windows 7.

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Answer by J
on 13 Mar 2012

Same annoying problem here. Stick with radians and pray it doesn't suffer a similar issue:
>> cosd(0)
ans =
1
>> cosd(0)
ans =
0
>> cosd(0)
ans =
0
>> ver
-------------------------------------------------------------------------------------
MATLAB Version 7.11.0.584 (R2010b)
MATLAB License Number: ###### [SCd censored license]
Operating System: Microsoft Windows 7 Version 6.1 (Build 7601: Service Pack 1)
Java VM Version: Java 1.6.0_17-b04 with Sun Microsystems Inc. Java HotSpot(TM) 64-Bit Server VM mixed mode
-------------------------------------------------------------------------------------

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Answer by Aldin
on 13 Mar 2012

The result is consistent for MATLAB 1.9. (R2009b)

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Answer by Ivan
on 2 Apr 2012

I have the same issue. R2010b. OS Win7 x64.

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Answer by Jan
on 20 Apr 2012

It would be nice to have a list of all affected functions here. The title of this thread "(cosd, sind etc.)" implies, that further functions suffer from this bug.

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