It looks like you're new here. If you want to get involved, click one of these buttons!

- 140.7K All Categories
- 103.5K Programming Languages
- 6.5K Assembler Developer
- 1.9K Basic
- 39.9K C and C++
- 2.9K C#
- 7.9K Delphi and Kylix
- 4 Haskell
- 9.7K Java
- 4.1K Pascal
- 1.3K Perl
- 2K PHP
- 538 Python
- 37 Ruby
- 4.4K VB.NET
- 1.6K VBA
- 20.8K Visual Basic
- 2.6K Game programming
- 315 Console programming
- 90 DirectX Game dev
- 1 Minecraft
- 111 Newbie Game Programmers
- 2 Oculus Rift
- 9K Applications
- 1.8K Computer Graphics
- 738 Computer Hardware
- 3.4K Database & SQL
- 535 Electronics development
- 1.6K Matlab
- 628 Sound & Music
- 257 XML Development
- 3.3K Classifieds
- 198 Co-operative Projects
- 196 For sale
- 190 FreeLance Software City
- 1.9K Jobs Available
- 602 Jobs Wanted
- 207 Wanted
- 2.9K Microsoft .NET
- 1.8K ASP.NET
- 1.1K .NET General
- 3.4K Miscellaneous
- 8 Join the Team
- 354 Comments on this site
- 69 Computer Emulators
- 2.1K General programming
- 187 New programming languages
- 621 Off topic board
- 186 Mobile & Wireless
- 60 Android
- 124 Palm Pilot
- 338 Multimedia
- 154 Demo programming
- 184 MP3 programming
- 0 Bash scripts
- 23 Cloud Computing
- 53 FreeBSD
- 1.7K LINUX programming
- 370 MS-DOS
- 0 Shell scripting
- 321 Windows CE & Pocket PC
- 4.1K Windows programming
- 930 Software Development
- 416 Algorithms
- 68 Object Orientation
- 90 Project Management
- 93 Quality & Testing
- 262 Security
- 7.6K WEB-Development
- 1.8K Active Server Pages
- 61 AJAX
- 2 Bootstrap Themes
- 55 CGI Development
- 28 ColdFusion
- 224 Flash development
- 1.4K HTML & WEB-Design
- 1.4K Internet Development
- 2.2K JavaScript
- 35 JQuery
- 298 WEB Servers
- 145 WEB-Services / SOAP

coolpursuit
Member Posts: **1**

in Matlab

I'm College student, and now studying Matlab.

I saw a verification problem. problem is following...

EXAMPLE

Let x(n) be a random sequence uniformly distributed between [0,1] over 0> x = rand(1,11); n=0:10;

>> k = 0:500; w = (pi/500)*k;

>> X = x * (exp(-j*pi/500)).^(n'*k); % DTFT of x

>>

>> y = x; m = n+2;

>> Y = y * (exp(-j*pi/500)).^(m'*k); % DTFT of y

>>

>> % verification

>> Y_check = (exp(-j*2).^w).*X;

>> error = max(abs(Y-Y_check)); % difference

error =

5.77e-015

My question is that,

1) What is the reason that error is NOT zero?

error is very very marginal value, but I think, that error must be zero in digital calculation(like MATLAB)

Could you tell me the reason?

2) and, if there is way that error be zero, Could you teach me about that?

Before that EXAMPLE, I think that all digital calculation has same result.

for example, 1 + 2 + 3 = 6

Anytime, and by any computer, 1 + 2 + 3 = 6.

I really really want to know about that.

Please someone answer my question...

I saw a verification problem. problem is following...

EXAMPLE

Let x(n) be a random sequence uniformly distributed between [0,1] over 0> x = rand(1,11); n=0:10;

>> k = 0:500; w = (pi/500)*k;

>> X = x * (exp(-j*pi/500)).^(n'*k); % DTFT of x

>>

>> y = x; m = n+2;

>> Y = y * (exp(-j*pi/500)).^(m'*k); % DTFT of y

>>

>> % verification

>> Y_check = (exp(-j*2).^w).*X;

>> error = max(abs(Y-Y_check)); % difference

error =

5.77e-015

My question is that,

1) What is the reason that error is NOT zero?

error is very very marginal value, but I think, that error must be zero in digital calculation(like MATLAB)

Could you tell me the reason?

2) and, if there is way that error be zero, Could you teach me about that?

Before that EXAMPLE, I think that all digital calculation has same result.

for example, 1 + 2 + 3 = 6

Anytime, and by any computer, 1 + 2 + 3 = 6.

I really really want to know about that.

Please someone answer my question...

Terms of use / Privacy statement / Publisher: Lars Hagelin

Programmers Heaven articles / Programmers Heaven files / Programmers Heaven uploaded content / Programmers Heaven C Sharp ebook / Operated by CommunityHeaven

© 1997-2015 Programmersheaven.com - All rights reserved.

## Comments

41They are working with a limited number of bits and bytes, and that

creates a problem...

You're not working with continuous values but with discrete ones, and

you'll loose the information in between those discrete values.

For example, calculate this simple operation, manually and with Matlab

3*(4/3 - 1) - 1

What did you expect?