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pub
pi
Commits
c28495fc
Commit
c28495fc
authored
Mar 01, 2020
by
Neil Gershenfeld
Browse files
wip
parent
6bacca84
Pipeline
#5096
passed with stage
in 1 second
Changes
2
Pipelines
1
Hide whitespace changes
Inline
Side-by-side
C++/threadpi.cpp
0 → 100755
View file @
c28495fc
//
// threadpi.cpp
// Neil Gershenfeld 3/1/20
// calculation of pi by a C++ thread sum
// pi = 3.14159265358979323846
//
#include
<iostream>
#include
<chrono>
#include
<thread>
#include
<vector>
unsigned
int
npts
=
2e7
;
unsigned
int
nthreads
=
std
::
thread
::
hardware_concurrency
();
std
::
vector
<
double
>
results
(
nthreads
);
void
sum
(
int
index
)
{
unsigned
int
start
=
npts
*
index
+
1
;
unsigned
int
end
=
npts
*
(
index
+
1
)
+
1
;
double
result
=
0
;
for
(
unsigned
int
i
=
start
;
i
<
end
;
++
i
)
result
+=
0.5
/
((
i
-
0.75
)
*
(
i
-
0.25
));
results
[
index
]
=
result
;
}
int
main
(
void
)
{
double
pi
=
0
;
std
::
thread
threads
[
nthreads
];
auto
tstart
=
std
::
chrono
::
high_resolution_clock
::
now
();
for
(
int
i
=
0
;
i
<
nthreads
;
++
i
)
threads
[
i
]
=
std
::
thread
(
sum
,
i
);
for
(
int
i
=
0
;
i
<
nthreads
;
++
i
)
{
threads
[
i
].
join
();
pi
+=
results
[
i
];
}
auto
tend
=
std
::
chrono
::
high_resolution_clock
::
now
();
auto
dt
=
std
::
chrono
::
duration_cast
<
std
::
chrono
::
microseconds
>
(
tend
-
tstart
).
count
();
auto
mflops
=
npts
*
nthreads
*
5.0
/
dt
;
std
::
cout
<<
"npts: "
<<
npts
<<
" nthreads: "
<<
nthreads
<<
" pi: "
<<
pi
<<
'\n'
;
std
::
cout
<<
"time: "
<<
1e-6
*
dt
<<
" estimated MFlops: "
<<
mflops
<<
'\n'
;
return
0
;
}
README.md
View file @
c28495fc
...
...
@@ -10,6 +10,7 @@
|1,090|
[
numbapig.py
](
Python/numbapig.py
)
|Python, Numba, CUDA, 5120 cores|NVIDIA V100|March 1, 2020|
|315|
[
numbapip.py
](
Python/numbapip.py
)
|Python, Numba, parallel, fastmath
<br>
96 cores|Intel 2x Xeon Platinum 8175M|Feb 7, 2020|
|272|
[
threadpi.c
](
C/threadpi.c
)
|C, 96 threads
<br>
gcc threadpi.c -o threadpi -O3 -ffast-math -pthread|Intel 2x Xeon Platinum 8175M|Jun 3, 2019|
|267|
[
threadpi.cpp
](
C++/threadpi.cpp
)
|C++, 96 threads
<br>
g++ threadpi.cpp -o threadpi -O3 -ffast-math -pthread|Intel 2x Xeon Platinum 8175M|Mar 1, 2020|
|211|
[
mpipi2.c
](
MPI/mpipi2.c
)
|C, MPI, 1 node, 96 cores
<br>
mpicc mpipi2.c -o mpipi2 -O3 -ffast-math|Intel 2x Xeon Platinum 8175M|Oct 24, 2019|
|180|
[
mpipi2.py
](
Python/mpipi2.py
)
|Python, Numba, MPI
<br>
mpirun -np 96 python mpipi2.py|Intel 2x Xeon Platinum 8175M|Feb 6, 2020|
|173|
[
mppi.c
](
OpenMP/mppi.c
)
|C, OpenMP, 96 threads
<br>
gcc mppi.c -o mppi -O3 -ffast-math -fopenmp|Intel 2x Xeon Platinum 8175M|Jul 1, 2019|
...
...
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