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poisson.c
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Created
Sun, Oct 20, 12:35
Size
1 KB
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text/x-c
Expires
Tue, Oct 22, 12:35 (2 d)
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blob
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21812223
Attached To
rSCINTROPARALLEL Poisson code for introduction to parallelism
poisson.c
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#include "io_ascii.h"
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#define N 256
int
main
()
{
int
i
,
j
;
char
k
;
float
**
u
;
float
**
uo
;
float
**
f
;
float
h
;
h
=
1.
/
(
N
+
1
);
// Allocation of arrays of pointers (columns)
u
=
(
float
**
)
malloc
((
N
+
1
)
*
sizeof
(
float
*
));
uo
=
(
float
**
)
malloc
((
N
+
1
)
*
sizeof
(
float
*
));
f
=
(
float
**
)
malloc
((
N
+
1
)
*
sizeof
(
float
*
));
// allocation of the rows
for
(
i
=
0
;
i
<
N
+
1
;
i
++
)
{
u
[
i
]
=
(
float
*
)
malloc
((
N
)
*
sizeof
(
float
));
uo
[
i
]
=
(
float
*
)
malloc
((
N
)
*
sizeof
(
float
));
f
[
i
]
=
(
float
*
)
malloc
((
N
)
*
sizeof
(
float
));
}
// initialization of u0 and f
for
(
i
=
0
;
i
<
N
+
1
;
i
++
)
{
for
(
j
=
0
;
j
<
N
+
1
;
j
++
)
{
u
[
i
][
j
]
=
0
;
uo
[
i
][
j
]
=
0
;
f
[
i
][
j
]
=
-
2.
*
100.
*
M_PI
*
M_PI
*
sin
(
10.
*
M_PI
*
i
*
h
)
*
sin
(
10.
*
M_PI
*
j
*
h
);
}
}
for
(
k
=
0
;
k
<
200
;
++
k
)
{
for
(
i
=
0
;
i
<
N
;
i
++
)
{
for
(
j
=
0
;
j
<
N
;
j
++
)
{
// computation of the new step
u
[
i
][
j
]
=
0.25
*
(
uo
[
i
-
1
][
j
]
+
uo
[
i
+
1
][
j
]
+
uo
[
i
][
j
-
1
]
+
uo
[
i
][
j
+
1
]
-
f
[
i
][
j
]
*
h
*
h
);
}
}
// copy new grid in old grid
for
(
i
=
0
;
i
<
N
+
1
;
i
++
)
{
for
(
j
=
0
;
j
<
N
+
1
;
j
++
)
{
uo
[
i
][
j
]
=
u
[
i
][
j
];
}
}
write_to_file
(
N
+
1
,
u
,
k
,
-
1.
,
1.
);
}
// de-allocation of the rows
for
(
i
=
0
;
i
<
N
+
1
;
i
++
)
{
free
(
u
[
i
]);
free
(
uo
[
i
]);
free
(
f
[
i
]);
}
return
0
;
}
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