change thread

tasks/mapping.wdl

@@ -18,7 +18,7 @@ task mapping {
 		STAR --genomeDir ${SAref_dir} --readFilesIn ${fastq_1} ${fastq_2} --readFilesCommand zcat --runThreadN 20 --outFileNamePrefix OnePass_ 
 
 		genomeDir=./twoPass
-		STAR --runMode genomeGenerate --genomeDir $genomeDir --genomeFastaFiles ${STref_dir}/${fasta} --sjdbFileChrStartEnd OnePass_SJ.out.tab --sjdbOverhang 75 --runThreadN 20
+		STAR --runMode genomeGenerate --genomeDir $genomeDir --genomeFastaFiles ${STref_dir}/${fasta} --sjdbFileChrStartEnd OnePass_SJ.out.tab --sjdbOverhang 75 --runThreadN 12
 
 
 		STAR --genomeDir $genomeDir --readFilesIn ${fastq_1} ${fastq_2} --readFilesCommand zcat --runThreadN 20 --outFileNamePrefix ${sample}_