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Thread Subject:
Singular Value Decomposition

Subject: Singular Value Decomposition

From: Ashley Daly

Date: 9 Mar, 2009 14:34:01

Message: 1 of 5

I need to write a program that first gives the following details:

load durer, image(X); colormap(hot); axis image, axis off

load detail, image(X); colormap(hot); axis image, axis off

The matrix X is a 359x371 matrix.
The command [U,S,V]=svd(X,0) gives the thin SVD of X.

For any value 1<=k<=359, one can obtain the truncated SVD X_k from the leading k columns of U and V, and the largest k singular values in S.

Write a Matlab program that outputs the smallest value of k for which ||X_k - X||_2 <= 700 and displays the images corresponding to X and X_k.

Use a single Matlab expression to determine k.
Use a single Matlab expression to compute the matrix X_k.

I have absolutely no idea where to even start. Unfortunately, my grandfather died last week, so I've had no time to even look at this, and I have to get it done in 2 days! I've loaded the first two items, and used the command to generate the thin SVD of X. I know that ||X_k - X||_2 is equal to the k+1-th singular value, but I'm not sure how to get that. Can anyone help me out a little? Thank you SO much.

Subject: Singular Value Decomposition

From: John D'Errico

Date: 9 Mar, 2009 15:05:03

Message: 2 of 5

"Ashley Daly" <kl0vis3000@hotmail.com> wrote in message <gp39cp$87p$1@fred.mathworks.com>...
> I need to write a program that first gives the following details:

(snip)

> I have absolutely no idea where to even start. Unfortunately, my grandfather died last week, so I've had no time to even look at this, and I have to get it done in 2 days! I've loaded the first two items, and used the command to generate the thin SVD of X. I know that ||X_k - X||_2 is equal to the k+1-th singular value, but I'm not sure how to get that. Can anyone help me out a little? Thank you SO much.

Yeah, yeah.

My dog died.
My father died.
My sister died.
My sister got pregnant.
The rabbit died.

I've probably missed a few, the list goes on
and on. Learn to do your homework on time.
Learn to do your own homework, period.

john

Subject: Singular Value Decomposition

From: Ashley Daly

Date: 9 Mar, 2009 20:15:04

Message: 3 of 5

Wow, thanks for your sympathy, John. I had to make a 1400 mile roundtrip up to Massachusetts to spend all last week with my family to deal with my grampa's passing. Next time, I'll ask my family members to plan their deaths around my homework. Thanks again.

Subject: Singular Value Decomposition

From: Rune Allnor

Date: 9 Mar, 2009 20:48:13

Message: 4 of 5

On 9 Mar, 21:15, "Ashley Daly" <kl0vis3...@hotmail.com> wrote:
> Wow, thanks for your sympathy, John. I had to make a 1400 mile roundtrip =
up to Massachusetts to spend all last week with my family to deal with my g=
rampa's passing. Next time, I'll ask my family members to plan their deaths=
 around my homework. Thanks again.

If your story is true, tell your supervisor and get
an extension on your project. People here don't help
out with homework, particularly not when time is
short. That's a sign of poor planning on behalf of
the students, and no one have any interest in helping
with a mess the students have got themselves into.

Rune

Subject: Singular Value Decomposition

From: Ruben osa

Date: 7 Oct, 2009 15:39:02

Message: 5 of 5

"Ashley Daly" <kl0vis3000@hotmail.com> wrote in message <gp39cp$87p$1@fred.mathworks.com>...
> I need to write a program that first gives the following details:
>
> load durer, image(X); colormap(hot); axis image, axis off
>
> load detail, image(X); colormap(hot); axis image, axis off
>
> The matrix X is a 359x371 matrix.
> The command [U,S,V]=svd(X,0) gives the thin SVD of X.
>
> For any value 1<=k<=359, one can obtain the truncated SVD X_k from the leading k columns of U and V, and the largest k singular values in S.
>
> Write a Matlab program that outputs the smallest value of k for which ||X_k - X||_2 <= 700 and displays the images corresponding to X and X_k.
>
> Use a single Matlab expression to determine k.
> Use a single Matlab expression to compute the matrix X_k.
>
> I have absolutely no idea where to even start. Unfortunately, my grandfather died last week, so I've had no time to even look at this, and I have to get it done in 2 days! I've loaded the first two items, and used the command to generate the thin SVD of X. I know that ||X_k - X||_2 is equal to the k+1-th singular value, but I'm not sure how to get that. Can anyone help me out a little? Thank you SO much.

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