| <html>
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| <head>
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| <title>shmem_float_p</title>
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| </head>
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| <h2 id="top">shmem_float_p</h2>
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| <h4>Purpose</h4>
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|
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|
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| <p>Transfers one data item to a remote Processing Element (PE).
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| </p>
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|
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| <h4>C syntax</h4>
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|
|
| <pre>
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| #include <shmem.h>
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|
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| void shmem_float_p(float *addr, float value, int pe);
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|
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| </pre>
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|
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| <h4>Parameters</h4>
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|
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|
|
| <dl>
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| <dt class="bold">INPUT</dt>
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| <dd>
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|
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| </dd>
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| <dt class="bold ">addr</dt>
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| <dd>The remotely accessible data object which will receive the data on the remote PE.
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| </dd>
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| <dt class="bold ">value</dt>
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| <dd>The value to be transferred to addr on the remote PE.
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| </dd>
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| <dt class="bold">pe</dt>
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| <dd>Processing element number of the remote PE.
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|
|
| </dd>
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| </dl>
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| <h4>Description</h4>
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|
|
| <div class="ledi">
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| <p>This routine provides a very low latency remote read write capability for single elements
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| of most basic types</p>
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| <p>This function starts the remote transfer and may return before
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| the data is delivered to the remote PE. To enforce the ordering/completion of the put routines, the use of shmem_fence, shmem_quiet, shmem_barrier or shmem_barrier_all is needed.</p>
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| <p>The function shmem_float_p() transfers a float data item to the remote PE.</p>
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|
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| <h4>IBM NOTES</h4>
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| <div class="ledi">
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| <dl>
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| <p>Please refer to Atomicity and Coherency section for atomicity and coherence model in the OpenSHMEM documentation</p>
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| </dd>
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| </dl>
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|
|
| <h4>C examples</h4>
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| <pre>
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| #include <stdlib.h>
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| #include <stdio.h>
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|
|
| #include <shmem.h>
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|
|
| #define GLOBAL_ARRAY_SIZE 10
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| #define INT_INIT_VALUE 1234
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| //can not use #define
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| const float FLOAT_INIT_VALUE = 1234.123456;
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|
|
| static float gFloatElement = 0;
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| static float gFloatArray[GLOBAL_ARRAY_SIZE] = {0};
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|
|
| static int gIntElement = 0;
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| static int gIntArray[GLOBAL_ARRAY_SIZE] = {0};
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|
|
| int main (int argc, char* argv[])
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| {
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| int total_tasks = -1;
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| int my_task = -1;
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|
|
| start_pes(0);
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|
|
| total_tasks = _num_pes();
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|
|
| if (total_tasks <= 0) {
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| printf("FAILED\n");
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| exit(1);
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| } else {
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| printf("number of pes is %d\n", total_tasks);
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| }
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|
|
| if (total_tasks < 2 || total_tasks % 2) {
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| printf("FAILED: The number of pes should be an even number. (at least 2)\n");
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| exit(1);
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| }
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|
|
| my_task = _my_pe();
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|
|
| if (my_task < 0){
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| printf("FAILED\n");
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| exit(1);
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| } else {
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| printf("my pe id is %d\n", my_task);
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| }
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|
|
| printf("The address of gIntElement is %p\n", &gIntElement);
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| printf("The address of gIntArray is %p\n", gIntArray);
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|
|
| printf("The address of gFloatElement is %p\n", &gFloatElement);
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| printf("The address of gFloatArray is %p\n", gFloatArray);
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|
|
| // even tasks put value to odd tasks
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| if (my_task%2 == 0) {
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| int tgt_task = my_task + 1;
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|
|
| //for int
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| gIntElement = INT_INIT_VALUE;
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| for (int i=0; i<GLOBAL_ARRAY_SIZE; i++) {
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| gIntArray[i] = INT_INIT_VALUE;
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| }
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|
|
| shmem_int_p(&gIntElement, gIntElement, tgt_task);
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| shmem_int_put(gIntArray, gIntArray, GLOBAL_ARRAY_SIZE, tgt_task);
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|
|
| //for float
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| gFloatElement = FLOAT_INIT_VALUE;
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| for (int i=0; i<GLOBAL_ARRAY_SIZE; i++) {
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| gFloatArray[i] = FLOAT_INIT_VALUE;
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| }
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|
|
| shmem_float_p(&gFloatElement, gFloatElement, tgt_task);
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| shmem_float_put(gFloatArray, gFloatArray, GLOBAL_ARRAY_SIZE, tgt_task);
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| }
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|
|
| shmem_barrier_all();
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|
|
| // odd tasks check value
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| if (my_task%2 == 1) {
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| //for int
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| if (gIntElement != INT_INIT_VALUE) {
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| printf("FAILED: element should be %d instead of %d\n", INT_INIT_VALUE, gIntElement);
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| exit(1);
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| }
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|
|
| for (int i=0; i<GLOBAL_ARRAY_SIZE; i++) {
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| if (gIntArray[i] != INT_INIT_VALUE) {
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| printf("FAILED, array[%d] should be %d instead of %d\n", i, INT_INIT_VALUE, gIntArray[i]);
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| }
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| }
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|
|
| //for float
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| if (gFloatElement != FLOAT_INIT_VALUE) {
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| printf("FAILED: element should be %f instead of %f\n", FLOAT_INIT_VALUE, gFloatElement);
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| exit(1);
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| }
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|
|
| for (int i=0; i<GLOBAL_ARRAY_SIZE; i++) {
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| if (gFloatArray[i] != FLOAT_INIT_VALUE) {
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| printf("FAILED, array[%d] should be %f instead of %f\n", i, FLOAT_INIT_VALUE, gFloatArray[i]);
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| }
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| }
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| }
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|
|
| shmem_barrier_all();
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|
|
| printf("PASSED\n");
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| return 0;
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| }
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| </pre>
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|
|
|
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| <h4>Related information</h4>
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|
|
| <p>Subroutines: shmem_barrier, shmem_put, shmem_fence, shmem_iput, shmem_quiet
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| </p>
|
| <hr><a href="apiIndex.html">OpenSHMEM API Index</a> |
| </html> |
