Questions tagged [unroll]
27 questions
66
votes
3 answers
Tell gcc to specifically unroll a loop
How can I tell GCC to unroll a particular loop?
I have used the CUDA SDK where loops can be unrolled manually using #pragma unroll. Is there a similar feature for gcc? I googled a bit but could not find anything.
Nils
- 13,319
- 19
- 86
- 108
17
votes
2 answers
Unlist a data frame by rows, not columns
A relatively simple question, but the answer seems to have eluded me. Currently, I have a data frame which looks similar to this:
0 0 0 1 1
0 1 0 1 1
2 1 1 0 3
I'm trying to turn this into a single line of data, by rows. I…
Gio Circo
- 332
- 2
- 9
16
votes
2 answers
Can scala splat be used for anything that isn't a varargs?
given e.g:
scala> def pipes(strings:String*) = strings.toList.mkString("|")
which I can call normally:
scala> pipes("foo", "bar")
res1: String = foo|bar
or with a splat:
scala> val args = List("a","b","c")
scala> pipes(args:_*)
res2: String =…
gfxmonk
- 8,614
- 5
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- 53
11
votes
1 answer
Why does the performance of my #pragma-unrolled loop degrade if the trip count is not constant?
I have following code using loop unrolling:
#pragma unroll
for (int i=0;i
small_potato
- 3,127
- 5
- 39
- 45
8
votes
1 answer
Does gcc automatically "unroll" if-statements?
Say I have a loop that looks like this:
for(int i = 0; i < 10000; i++) {
/* Do something computationally expensive */
if (i < 200 && !(i%20)) {
/* Do something else */
}
}
wherein some trivial task gets stuck behind an…
rayhem
- 741
- 1
- 8
- 23
5
votes
1 answer
How can I prevent a (serialized) expression to unroll
Thanks to the PowerShell expression mode, PowerShell has some nice ways to de-serialize objects, like:
the Invoke-Expression cmdlet
the Invoke-Command cmdlet
the call operator &
dot sourcing a PowerShell script file
My general expectation is that…
iRon
- 20,463
- 10
- 53
- 79
5
votes
1 answer
Add method call in test name with Unroll using Spock
I have a code and I want to put method invocation value in the name of the method.
@Unroll
def 'check #file other text'() {
setup:
def file = allProperties.keySet().getAt(0)
...
where:
...
Now…
Xelian
- 16,680
- 25
- 99
- 152
3
votes
0 answers
Specific case of unrolling an array to a function with arbitrary number and type of arguments
Important!
Existing answers imply that all function parameter types are the same, only the number of parameters varies.
For instance : Any Solution to Unpack a Vector to Function Arguments in C++?
It's not possible to use return func(args[I]...)…
galinette
- 8,896
- 2
- 36
- 87
3
votes
1 answer
Is there any difference between #pragma unroll(0) and #pragma unroll(1)?
I read the document about the loop unrolling.
It explains that if you set unrolling factor as 1, then the program will work like with #pragma nounrolling.
However, that documents does not include #pragma unroll(0) case..
Since the range of n is 0 to…
rae hyun kim
- 31
- 1
2
votes
2 answers
symbolic simulation in c c++
I am wondering if i could see the loop unrolled form of a C program. For example i have the following for loop
// The following code mimics functionality of a logic circuit whose
//inputs are a,b,c and d
//output f
//At every for loop iteration,…
user2065276
- 313
- 2
- 16
1
vote
1 answer
Spring-Boot and Spock fail when using Unroll
I'm setting up a demo project with Spring-Boot. For entity-persistence, I'm using Spring generated Repository implementations based on interfaces:
@Repository
public interface MovieRepository extends JpaRepository {
List…
BramP
- 51
- 6
1
vote
6 answers
Efficient by-hand loop unrolling
I have this C code:
for (k = 0; k < n_n; k++) {
if (k == i || k == j) continue;
dd=q2_vect[k]-q1_vect;
d2=dd*dd;
if (d2<0) {
a=1;
break;
}
}
For compiler optimization reasons (on the SPE of the Cell…
Open the way
- 26,225
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1
vote
1 answer
how unroll a matrix in R
For example, I have a matrix:
[,1] [,2] [,3] [,4]
[1,] 1 2 3 4
[2,] 5 6 7 8
[3,] 9 10 11 12
[4,] 13 14 15 16
I want it to become
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
[1,] 1 2 3 4 …
Frank
- 7,235
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1
vote
1 answer
Unrolled linked list arrays vs. nodes
I'm reading about unrolled linked lists and have found two different ways to make one. The book I have implements one like this:
// Node
typedef struct node {
int data;
struct node *next;
} Node;
// Block of nodes
typedef struct linkedblock…
Austin
- 6,921
- 12
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- 138
1
vote
1 answer
How to unroll a certain loop with certain params like max-unroll-times in GCC
How should I write my code if I want GCC to unroll one of loops in
my code with certain params like max-unroll-times in GCC?
zbhhbz
- 19
- 2