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Giovanni De Luca


12 total contributions since 2013

Professional Interests: Model Order Reduction

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Question


When does it happens the data-copy, when executing a parallel job?
Hello, when I call a function that I want to run in parallel (for example, inside a _parfor_ statement), and this function re...

6 years ago | 1 answer | 0

1

answer

Question


Parfor and data copy to workers
Hello, I read this brief explanation about when MATLAB does a copy of data when working with the PCT in http://www.mathwor...

6 years ago | 0 answers | 0

0

answers

Question


When working with, e.g., two parallel processes, with the PCT, is the RAM memory partitioned in two?
Hi. Assuming I have a function _my_fnc_ with input parameters two very-large size matrices _A_ and _B_ , and a (column) vector _...

6 years ago | 0 answers | 0

0

answers

Question


When calling the matlabpool to work in parallel, does each worker work in single-thread mode?
Hi, when I call a matlabpool of workers, and each worker has to compute a routine which is optimized by the BLAS subroutines (e....

6 years ago | 1 answer | 0

1

answer

Question


Is there a command for the PCT which allows to know the communication time spent by the client to send data to the workers?
Hi, I would know if there is a command or a way to know exactly the time spent in communication, for an embarrassangly parall...

6 years ago | 0 answers | 0

0

answers

Question


How does the client send data to the workes, when calling parfor?
Hi, let assume I want to use the parfor with my function (in this case, it just computes the routine without retrieving data fro...

6 years ago | 1 answer | 0

1

answer

Answered
If I call matlabpool open 4 and I have 4 cores, will I work in parallel with 4 or with 3 workers?
Thank you Thomas. Then, according to the first answer, if a call 4 workers the theoretical linear speedup I can obtain is 4, sin...

6 years ago | 0

Question


If I call matlabpool open 4 and I have 4 cores, will I work in parallel with 4 or with 3 workers?
Hi, I have a desktop machine with 4 cores available. 1) I wonder whether, calling a pool of 4 workers with the PCT, there wil...

6 years ago | 2 answers | 0

2

answers

Question


How to run a sequential code in a cluster workstation?
Hi, I have the opportunity to work with a cluster of computers in order to analyze the speed up, if any, of my parallelizable co...

6 years ago | 0 answers | 0

0

answers

Question


Why with running an intensive time-simulation routine in a local multi-core, with the parallel toolboxes, there is a slowdown respect to the sequential code, whilst with running the same code in a cluster workstation there is a speed up?
Hi, I implemented a code with a subroutine that is quite expensive in time simulation, the backslash operator in solving very l...

6 years ago | 0 answers | 0

0

answers

Answered
1) Why for dense matrices it's not useful to split B? 2) What are the factors that determine the speed up for the sparse case?
Thank you. The answer has been useful to understand the expensive cost of the factorization. Then, I've corrected my code: ...

6 years ago | 0

Question


1) Why for dense matrices it's not useful to split B? 2) What are the factors that determine the speed up for the sparse case?
I want to solve the linear system Ax=B for x, computing x=A\B, with B having m column-vector. This is one of the operations in m...

6 years ago | 2 answers | 0

2

answers