Prefix sums - Revision history

Polas: 8 revisions imported

2019-04-15T15:44:44Z

8 revisions imported

Polas: /* Download */

2013-01-19T13:32:20Z

‎Download

Polas: /* Notes */

2013-01-19T13:29:11Z

‎Notes

Polas: /* Source Code */

2013-01-19T13:28:46Z

‎Source Code

Polas: /* Source Code */

2013-01-19T13:28:28Z

‎Source Code

Polas at 14:21, 14 January 2013

2013-01-14T14:21:26Z

Polas at 11:36, 3 July 2010

2010-07-03T11:36:56Z

Polas: /* Download */

2010-01-11T17:25:02Z

‎Download

Polas: Created page with '== Overview == Prefix sums is a very simple, basic parallel algorithm commonly used as the building block of many applications. Also known as a scan, each process will sumate th…'

2010-01-10T23:02:45Z

Created page with '== Overview == Prefix sums is a very simple, basic parallel algorithm commonly used as the building block of many applications. Also known as a scan, each process will sumate th…'

New page

== Overview ==

Prefix sums is a very simple, basic parallel algorithm commonly used as the building block of many applications. Also known as a scan, each process will sumate their value with every preceding processes' value. For instance, p=0 returns its value, p=1 returns p=1 + p=0 values, p=2 returns p=2 + p=1 + p=0 values. The MPI reduce command often implements the communication via the logarithmic structure shown below.

== Source Code ==

function void main[var arga,var argb]
{
var m:=10;
var a:Int :: allocated[multiple[]];
var p;
par p from 0 to m - 1
{
var mine:Int;
mine:= randomnumber[0,toInt[argb#1]];
var i;
for i from 0 to m - 1
{
var myvalue:=mine;
if (i < p) myvalue:=0;
(a :: reduce[i, "sum"]):=myvalue;
};
print[p," = ",a,"\n"];
};
};

== Notes ==

The function main has been included here so that the user can provide, via command line options, the range of the random number to find. The complexity of the prefix sums is taken away by using the reduce primitive communication type.

== Download ==

@@ Line 36: / Line 36: @@
 == Download ==
-Download the entire prefix sums source code [http://www.mesham.com/downloads/prefix.mesh here]
+Download the entire prefix sums source code [http://www.mesham.com/downloads/prefix.mesh here] you can also download a legacy version for Mesham 0.5 [http://www.mesham.com/downloads/prefix-0.5.mesh here]
 [[Category:Example Codes]]

← Older revision		Revision as of 14:21, 14 January 2013
Line 33:		Line 33:

	Download the entire prefix sums source code [http://www.mesham.com/downloads/prefix.mesh here]		Download the entire prefix sums source code [http://www.mesham.com/downloads/prefix.mesh here]
		+
		+	[[Category:Example Codes]]

← Older revision		Revision as of 11:36, 3 July 2010
Line 1:		Line 1:
		+	<metadesc>Mesham is a type oriented programming language allowing the writing of high performance parallel codes which are efficient yet simple to write and maintain</metadesc>
	== Overview ==		== Overview ==

← Older revision		Revision as of 17:25, 11 January 2010
Line 30:		Line 30:

	== Download ==		== Download ==
		+
		+	Download the entire prefix sums source code [http://www.mesham.com/downloads/prefix.mesh here]

← Older revision	Revision as of 15:44, 15 April 2019
(No difference)

@@ Line 32: / Line 32: @@
 == Notes ==
-The function main has been included here so that the user can provide, via command line options, the range of the random number to find. The complexity of the prefix sums is taken away by using the reduce primitive communication type.
+The user can provide, via command line options, the range of the random number to find. The (relative) complexity of the prefix sums is taken away by using the reduce primitive communication type.
 == Download ==

@@ Line 6: / Line 6: @@
 == Source Code ==
-  function void main[var arga,var argb]
+ #include <maths>
+ #include <io>
-  var m:=10;
+ #include <string>
-  var a:Int :: allocated[multiple[]];
-  var p;
+ var processes:=10;
-  par p from 0 to m - 1
+  function void main(var argc:Int,var argv:array[String]) {
-    var mine:Int;
+    var a:Int :: allocated[multiple[]];
-    mine:= randomnumber[0,toInt[argb#1]];
+    var p;
-    var i;
+    par p from 0 to processes - 1 {
-    for i from 0 to m - 1
+       var mine:Int;	// Force to be an integer as randomnumber function defaults to double
+       mine:= randomnumber(0,toint(argv[1]));
-      var myvalue:=mine;
+       var i;
-      if (i < p) myvalue:=0;
+       for i from 0 to processes - 1 {
-      (a :: reduce[i, "sum"]):=myvalue;
+          var myvalue:=mine;
      };
   };