Search help

Note: Searching from the top-level index page will search all documents. Searching from a specific document will search only that document.

Find an exact phrase: Wrap your search phrase in "" (double quotes) to only get results where the phrase is exactly matched. For example "PyTorch for the IPU" or "replicated tensor sharding"
Prefix query: Add an * (asterisk) at the end of any word to indicate a prefix query. This will return results containing all words with the specific prefix. For example tensor*

Fuzzy search: Use ~N (tilde followed by a number) at the end of any word for a fuzzy search. This will return results that are similar to the search word. N specifies the “edit distance” (fuzziness) of the match. For example Polibs~1
Words close to each other: ~N (tilde followed by a number) after a phrase (in quotes) returns results where the words are close to each other. N is the maximum number of positions allowed between matching words. For example "ipu version"~2
Logical operators. You can use the following logical operators in a search:
- + signifies AND operation
- | signifies OR operation
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- () controls operator precedence

5. Example code and usage

5.1. Linking

When compiling your program, you will need to add the libraries used by the linker. The Poplar SDK contains the shared library file for GCL named libgcl.so and after activating the Poplar SDK, it will be available for linking after specifying -lgcl. For example:

$ g++ -std=c++11 my-program.cpp -lpoplar -lpopops -lgcl

5.2. Example code

A full example of an invocation of the AllReduce operation on two replicas using GCL is available. The graph creation code is shown in Listing 5.1.

Listing 5.1 gcl_allreduce_example.cpp

  // Main program
  program::Sequence prog;
  prog.add(program::Copy(inStream, data));
  gcl::allReduceInPlaceCrossReplica(graph, data, gcl::CollectiveOperator::ADD,
                                    prog);

You can download the complete code and compile it with the command:

$ g++ gcl_allreduce_example.cpp -lpoplar -lpopops -lgcl \
      -o gcl_allreduce_example

Download gcl_allreduce_example.cpp