32 total contributions since 2011

Professional Interests: signal processing in MRI

Submitted

A safety net for MATLAB's clear command

intercept amok calls to clear() in interactive mode

1 year ago | 1 downloads |

Responded

Re: How Comparing a BIG matrix with itself after execution "while loops"? (no loss of memory)

For me (R2014a, Linux), calling isequal(O,Onew) does not require more memory than idling around with those arrays in the workspa...

2 years ago | 1193 views

Responded

Re: speed of matrix multiplication

My tests were in 2014a on a 8-core Xeon server (2 quadcore CPUs). With 2012a, the direct multiplication is stil slower (but 1s f...

2 years ago | 2230 views

Responded

Re: speed of matrix multiplication

Bruno, thanks for your reply. I attempted to think about the implementation, too; but since mtimes() uses optimized LAPACK lib...

2 years ago | 2230 views

Posted

speed of matrix multiplication

Hi, I found a really weird performance issue with mtimes for pretty large matrices. Look at my test function. A better formatt...

2 years ago | 2230 views

Answered

how do I plot one channel of data when I have 100 channels?

data = randn(100,300); % bad example for actual data channel = 76; % select channel to plot figure, plot(...

how do I plot one channel of data when I have 100 channels?

data = randn(100,300); % bad example for actual data channel = 76; % select channel to plot figure, plot(...

3 years ago | 0

| accepted

Submitted

simulate motion in Cartesian MRI

Simulates Point Spread Function (PSF) and k-space data for motion in Cartesian sequences.

3 years ago | 7 downloads |

Submitted

MRI Partial Fourier reconstruction with POCS

Fast and robust reconstruction of Cartesian partial Fourier MRI data with POCS

4 years ago | 23 downloads |

Submitted

hypersphere / n-sphere

Generate n-dimensional Ellipsoid or Sphere

4 years ago | 9 downloads |

Submitted

Execute default function of a MATLAB installation

Execute the default function available as an m-file in MATLAB's installation directory.

4 years ago | 0 downloads |

Answered

To find the maximum value in a matrix?

more general: |max(A(:))|

To find the maximum value in a matrix?

more general: |max(A(:))|

4 years ago | 6

| accepted

Responded

Re: contourf() strange with only few levels

Armin, I created a wrapper for the colormap function, intended to use more shadings: http://www.mathworks.com/matlabcentral/fil...

4 years ago | 2703 views

Solved

Finding Perfect Squares

Given a vector of numbers, return true if one of the numbers is a square of one of the other numbers. Otherwise return false. E...

5 years ago

Solved

Triangle Numbers

Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3 which can be displa...

5 years ago

Solved

Summing digits

Given n, find the sum of the digits that make up 2^n. Example: Input n = 7 Output b = 11 since 2^7 = 128, and 1 + ...

5 years ago

Solved

Remove the vowels

Remove all the vowels in the given phrase. Example: Input s1 = 'Jack and Jill went up the hill' Output s2 is 'Jck nd Jll wn...

5 years ago

Solved

Select every other element of a vector

Write a function which returns every other element of the vector passed in. That is, it returns the all odd-numbered elements, s...

5 years ago

Solved

Swap the first and last columns

Flip the outermost columns of matrix A, so that the first column becomes the last and the last column becomes the first. All oth...

5 years ago

Solved

Column Removal

Remove the nth column from input matrix A and return the resulting matrix in output B. So if A = [1 2 3; 4 5 6]; and ...

5 years ago

Solved

Make the vector [1 2 3 4 5 6 7 8 9 10]

In MATLAB, you create a vector by enclosing the elements in square brackets like so: x = [1 2 3 4] Commas are optional, s...

5 years ago

Solved

Who Has the Most Change?

You have a matrix for which each row is a person and the columns represent the number of quarters, nickels, dimes, and pennies t...

5 years ago

Solved

Find all elements less than 0 or greater than 10 and replace them with NaN

Given an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN. Example: Input ...

5 years ago

Solved

Make a checkerboard matrix

Given an integer n, make an n-by-n matrix made up of alternating ones and zeros as shown below. The a(1,1) should be 1. Example...

5 years ago

Solved

Determine if input is odd

Given the input n, return true if n is odd or false if n is even.

5 years ago

Solved

Find the sum of all the numbers of the input vector

Find the sum of all the numbers of the input vector x. Examples: Input x = [1 2 3 5] Output y is 11 Input x ...

5 years ago

Responded

Re: Info about omitted 1st output from within function

It seems that you are right from a practical point of view. My problem is rather large and computationally demanding, with typic...

5 years ago | 2367 views

Responded

Re: Info about omitted 1st output from within function

You are totally right, a&b together is much faster than one after another. But as I wrote earlier, 'a' and 'b' are the outputs o...

5 years ago | 2367 views

Responded

Re: Info about omitted 1st output from within function

Right, that's what I'm doing now, instead. This is just starting to get quite messy, because myfun() is a cost function of the f...

5 years ago | 2367 views

Responded

Thanks (Re: Info about omitted 1st output from within function)

Okay, that is at least a plain and useful answer. Thanks.

5 years ago | 2367 views