1 Troubleshooting

A common issue that comes up when running spiec.easi is coming up with an empty network after running StARS.

For example:

library(SpiecEasi)
data(amgut1.filt)

pargs <- list(seed=10010)
se3 <- spiec.easi(amgut1.filt, method='mb', lambda.min.ratio=5e-1, nlambda=10, pulsar.params=pargs)
getOptInd(se3)
# [1] 1
sum(getRefit(se3))/2
# [1] 139

As the warning indicates, the network stability could not be determined from the lambda path. Looking at the stability along the lambda path, se$select$stars$summary, we can see that the maximum value of the StARS summary statistic never crosses the default threshold (0.05).

This problem we can fix by lowering lambda.min.ratio to explore denser networks:

se4 <- spiec.easi(amgut1.filt, method='mb', lambda.min.ratio=1e-1, nlambda=10, pulsar.params=pargs)

We have now fit a network, but since we have only a rough, discrete sampling of networks along the lambda path, we should check how far we are from the target stability threshold (0.05):

getStability(se4)
# [1] 0.0003237095
sum(getRefit(se4))/2
# [1] 158

To get closer to the mark, we should bump up nlambda to more finely sample of the lambda path, which gives a denser network:

se5 <- spiec.easi(amgut1.filt, method='mb', lambda.min.ratio=1e-1, nlambda=100, pulsar.params=pargs)
getStability(se5)
# [1] 0.0003237095
sum(getRefit(se5))/2
# [1] 210

1.1 Common issues and solutions

1.1.1 1. Empty networks

Problem: After running spiec.easi, you get an empty network (no edges).

Solutions: - Lower lambda.min.ratio to explore denser networks - Increase nlambda for finer sampling of the lambda path - Check if your data has sufficient signal-to-noise ratio - Try different methods (‘mb’ vs ‘glasso’)

1.1.2 2. Very dense networks

Problem: The inferred network has too many edges.

Solutions: - Increase lambda.min.ratio to explore sparser networks - Adjust the StARS threshold in pulsar.params - Use cross-validation instead of StARS

1.1.3 3. Computational issues

Problem: The analysis takes too long or runs out of memory.

Solutions: - Use parallel processing with ncores parameter (Unix-like systems only) - Use B-StARS method for large datasets - Reduce rep.num in pulsar.params - Use batch mode for HPC clusters

1.1.4 4. Windows parallel processing issues

Problem: Error “‘mc.cores’ > 1 is not supported on Windows”

Solutions: - Use ncores=1 for serial processing on Windows - Use snow cluster for parallel processing on Windows:

library(parallel)
cl <- makeCluster(4, type = "SOCK")
pargs.windows <- list(rep.num=50, seed=10010, cluster=cl)
se.windows <- spiec.easi(data, method='mb', pulsar.params=pargs.windows)
stopCluster(cl)
  • Use batch mode which works on all platforms
  • Consider using WSL (Windows Subsystem for Linux) for Unix-like environment

1.1.5 5. Convergence issues

Problem: The algorithm doesn’t converge or gives warnings.

Solutions: - Check data preprocessing and normalization - Ensure data doesn’t have constant columns - Try different starting values - Check for missing or infinite values

1.1.6 6. Memory issues

Problem: R runs out of memory during analysis.

Solutions: - Use sparse matrices where possible - Reduce dataset size by filtering rare taxa - Use batch processing for large datasets - Increase system memory if available

1.2 Platform-specific considerations

1.2.1 Windows users:

  • Default parallel processing (mc.cores > 1) is not supported
  • Use ncores=1 for serial processing
  • Use snow cluster for parallel processing
  • Consider batch mode for large datasets

1.2.2 Unix-like systems (Linux, macOS):

  • Full support for parallel processing with mc.cores
  • Can use ncores parameter directly
  • Both multicore and snow clusters available

1.3 Diagnostic functions

SpiecEasi provides several functions to help diagnose issues:

# Check stability along lambda path
getStability(se)

# Get optimal lambda index
getOptInd(se)

# Get summary statistics
se$select$stars$summary

# Check network density
sum(getRefit(se))/2

# Visualize stability curve
plot(se$select$stars$summary)

# Check platform information
.Platform$OS.type

1.4 Parameter tuning guidelines

1.4.1 For small datasets (< 100 samples, < 50 taxa):

  • lambda.min.ratio = 1e-2
  • nlambda = 20-50
  • rep.num = 20-50

1.4.2 For medium datasets (100-1000 samples, 50-200 taxa):

  • lambda.min.ratio = 1e-3
  • nlambda = 50-100
  • rep.num = 50-100
  • Use parallel processing (Unix-like systems only)

1.4.3 For large datasets (> 1000 samples, > 200 taxa):

  • lambda.min.ratio = 1e-4
  • nlambda = 100+
  • rep.num = 100+
  • Use B-StARS method
  • Consider batch processing

1.4.4 Windows-specific recommendations:

  • Use ncores=1 for serial processing
  • Use snow cluster for parallel processing
  • Consider batch mode for large datasets
  • Use B-StARS method to reduce computational time

Session info:

sessionInfo()
# R version 4.6.0 alpha (2026-04-05 r89794)
# Platform: x86_64-pc-linux-gnu
# Running under: Ubuntu 24.04.4 LTS
# 
# Matrix products: default
# BLAS:   /home/biocbuild/bbs-3.23-bioc/R/lib/libRblas.so 
# LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.12.0  LAPACK version 3.12.0
# 
# locale:
#  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
#  [3] LC_TIME=en_GB              LC_COLLATE=C              
#  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
#  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
#  [9] LC_ADDRESS=C               LC_TELEPHONE=C            
# [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
# 
# time zone: America/New_York
# tzcode source: system (glibc)
# 
# attached base packages:
# [1] stats     graphics  grDevices utils     datasets  methods   base     
# 
# other attached packages:
# [1] phyloseq_1.55.2  igraph_2.2.3     Matrix_1.7-5     SpiecEasi_1.99.5
# [5] BiocStyle_2.39.0
# 
# loaded via a namespace (and not attached):
#  [1] ade4_1.7-24                 tidyselect_1.2.1           
#  [3] dplyr_1.2.1                 farver_2.1.2               
#  [5] Biostrings_2.79.5           S7_0.2.1                   
#  [7] fastmap_1.2.0               digest_0.6.39              
#  [9] lifecycle_1.0.5             cluster_2.1.8.2            
# [11] survival_3.8-6              magrittr_2.0.5             
# [13] compiler_4.6.0              rlang_1.2.0                
# [15] sass_0.4.10                 tools_4.6.0                
# [17] yaml_2.3.12                 data.table_1.18.2.1        
# [19] knitr_1.51                  labeling_0.4.3             
# [21] S4Arrays_1.11.1             DelayedArray_0.37.1        
# [23] plyr_1.8.9                  RColorBrewer_1.1-3         
# [25] abind_1.4-8                 withr_3.0.2                
# [27] BiocGenerics_0.57.0         grid_4.6.0                 
# [29] stats4_4.6.0                multtest_2.67.0            
# [31] biomformat_1.39.16          ggplot2_4.0.2              
# [33] scales_1.4.0                iterators_1.0.14           
# [35] MASS_7.3-65                 dichromat_2.0-0.1          
# [37] tinytex_0.59                SummarizedExperiment_1.41.1
# [39] cli_3.6.5                   rmarkdown_2.31             
# [41] vegan_2.7-3                 crayon_1.5.3               
# [43] generics_0.1.4              otel_0.2.0                 
# [45] pulsar_0.3.13               reshape2_1.4.5             
# [47] ape_5.8-1                   cachem_1.1.0               
# [49] stringr_1.6.0               splines_4.6.0              
# [51] parallel_4.6.0              BiocManager_1.30.27        
# [53] XVector_0.51.0              matrixStats_1.5.0          
# [55] vctrs_0.7.2                 glmnet_4.1-10              
# [57] jsonlite_2.0.0              VGAM_1.1-14                
# [59] bookdown_0.46               IRanges_2.45.0             
# [61] S4Vectors_0.49.1            magick_2.9.1               
# [63] foreach_1.5.2               jquerylib_0.1.4            
# [65] glue_1.8.0                  codetools_0.2-20           
# [67] stringi_1.8.7               shape_1.4.6.1              
# [69] gtable_0.3.6                GenomicRanges_1.63.2       
# [71] tibble_3.3.1                pillar_1.11.1              
# [73] htmltools_0.5.9             Seqinfo_1.1.0              
# [75] huge_1.5.1                  R6_2.6.1                   
# [77] evaluate_1.0.5              lattice_0.22-9             
# [79] Biobase_2.71.0              bslib_0.10.0               
# [81] Rcpp_1.1.1                  permute_0.9-10             
# [83] SparseArray_1.11.13         nlme_3.1-169               
# [85] mgcv_1.9-4                  xfun_0.57                  
# [87] MatrixGenerics_1.23.0       pkgconfig_2.0.3