---
name: "allpairs_multicore"
section: "1"
platform: "linux"
package: "coop-computing-tools"
version: "1:7.14.5-1+b2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/allpairs_multicore"
---

# allpairs\_multicore(1)

executes All-Pairs workflow in parallel on a multicore machine

## NAME

**allpairs\_multicore** - executes All-Pairs workflow in parallel on a multicore machine

## SYNOPSIS

FCallparis\_multicore \[options\] *\<set A\>* *\<set B\>* *\<compare function\>*FT

## DESCRIPTION

**allpairs\_multicore** computes the Cartesian product of two sets (*\<set A\> and \<set B\>), generating a matrix where each cell* *M\[i,j\] contains the output of the function F (\<compare function\>) on* *objects A\[i\] (an item in \<set A\>) and B\[j\] (an item in* *\<set B\>). The resulting matrix is displayed on the standard output,* *one comparison result per line along with the associated X and Y indices.*

*For large sets of objects,* **allpairs\_multicore** *will use as many cores as* *you have available, and will carefully manage virtual memory to exploit* *locality and avoid thrashing. Because of this, you should be prepared for the* *results to come back in any order. If you want to further exploit the* *parallelism of executing All-Pairs workflows on multiple (multicore) machines,* *please refer to the* **[allpairs\_master(1)](/allpairs_master/1.md)** *utility.*

## OPTIONS

- **-b,--block-size=*\<items\>***

  *Block size: number of items to hold in memory at once. (default: 50% of RAM)*

- **-c,--cores=*\<cores\>***

  *Number of cores to be used. (default: # of cores in machine)*

- **-e,--extra-args=*\<args\>***

  *Extra arguments to pass to the comparison program.*

- **-d,--debug=*\<flag\>***

  *Enable debugging for this subsystem.*

- **-v,--version**

  *Show program version.*

- **-h,--help**

  *Display this message.*

## EXIT STATUS

*On success, returns zero.  On failure, returns non-zero.*

## EXAMPLES

*Let's suppose you have a whole lot of files that you want to compare all to* *each other, named FCaFT, FCbFT, FCcFT, and so on. Suppose that you also* *have a program named FCcompareitFT) that when invoked as FCcompareit a bFT* *will compare files FCaFT and FCbFT and produce some output summarizing the* *difference between the two, like this:*

```

```

-

   *a b are 45 percent similar*

*To use the allpairs framework, create a file called FCset.listFT that lists each of* *your files, one per line:*

```

```

-

   *a*\
    *b*\
    *c*\
    *...*

*Then, invoke* **allpairs\_multicore** *like this:*

```

```

-

   *% allpairs\_multicore set.list set.list compareit*

*The framework will carry out all possible comparisons of the objects, and print* *the results one by one (note that the first two columns are X and Y indices in* *the resulting matrix):*

```

```

-

   *1	1	a a are 100 percent similar*\
    *1	2	a b are 45 percent similar*\
    *1	3	a c are 37 percent similar*\
    *...*

## COPYRIGHT

*The Cooperative Computing Tools are Copyright (C) 2022 The University of Notre Dame.  This software is distributed under the GNU General Public License.  See the file COPYING for details.*

## SEE ALSO

- •

  *The Cooperative Computing Tools (***"http://ccl.cse.nd.edu/software/manuals"***)*

- •

  *All-Pairs User Manual (***"http://ccl.cse.nd.edu/software/manuals/allpairs.html"***)*

- •

  **[allpairs\_master(1)](/allpairs_master/1.md)**