cancel

Cancel blocks in pipeline that are running in parallel

Since R2023a

Syntax

cancel(pipeline)

Description

cancel(pipeline) stops all blocks in the pipeline that are currently running in a parallel environment. The function also prevents new blocks from being queued. The function has no effect on the blocks that have been completed prior to calling the function.

Examples

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Cancel Bioinformatics Pipeline Blocks Running in Parallel

Open Live Script

Import the pipeline and block objects needed for the example.

import bioinfo.pipeline.Pipeline
import bioinfo.pipeline.block.*

Create a pipeline.

P = Pipeline;

Add some pause blocks for illustration purposes. Each block pauses for 1 and 10 seconds, respectively.

PB1 = UserFunction(@() pause(1));
PB2 = UserFunction(@() pause(10));
addBlock(P,[PB1,PB2]);

Run the pipeline in parallel.

run(P,UseParallel=true);

Starting parallel pool (parpool) using the 'Processes' profile ...
Connected to parallel pool with 4 workers.

Let the pipeline run for a few seconds in parallel. Then cancel the pipeline while it is still running.

cancel(P);

Check the process table that contains the run status of each block. Set Expanded to true to expand the process table variable values which are in cell arrays.

t = processTable(P,Expanded=true)

t=2×5 table
         Block          Status          RunStart                 RunEnd              RunErrors    
    ________________    ______    ____________________    ____________________    ________________

    "UserFunction_1"    Error     26-Jul-2023 08:51:44    26-Jul-2023 08:51:44    {1×1 MException}
    "UserFunction_2"    Error     26-Jul-2023 08:51:44    26-Jul-2023 08:51:44    {1×1 MException}

You can extract more information from the process table. For example, check the run status of the first block.

PB1Info = t(1,:);
PB1Info.Status

ans = 
  RunStatus enumeration

    Error

Check any error message associated with the block.

PB1Info.RunErrors{:}

ans = 
  MException with properties:

    identifier: 'parallel:fevalqueue:ExecutionCancelled'
       message: 'Execution of the future was cancelled.'
         cause: {}
         stack: [0×1 struct]
    Correction: []