Gene Protein Expression Matrix Normalization
When to Use
Use this skill when the user wants to normalize a numeric expression matrix before plotting, clustering, or exploratory comparison.
Typical requests:
- "Normalize this gene expression matrix with log2"
- "Do z-score scaling across samples"
- "Map protein abundance values into 0 to 1"
When Not to Use
Do not use this skill for:
- Count-model normalization such as CPM, TPM, TMM, or DESeq2 size factors
- Batch correction or covariate adjustment
- Single-cell preprocessing workflows
- Matrices that contain missing,
Inf, orNaNvalues unless they are cleaned first
When to Read External Files
When executing the analysis, run:
Rscript scripts/main.R --input_file <matrix.csv> --output_dir <output_dir> --method <log2|zscore|minmax>
| Situation | File to Read | Purpose |
|-----------|--------------|---------|
| Need to execute the workflow | scripts/main.R | CLI entry point |
| Need algorithm details | references/algorithm.md | Method definitions and assumptions |
| Encounter an error | references/troubleshooting.md | Standard error codes and fixes |
| Need examples or baseline run details | references/cli-guide.md | Ready-to-run commands and test record |
| Need dependency declarations | DESCRIPTION | Runtime package list |
Usage
Rscript scripts/main.R \
--input_file tests/data/expression_matrix.csv \
--output_dir ./output \
--method log2 \
--pseudo_count 1 \
--seed 42
Arguments
| Short | Long | Type | Default | Description |
|-------|------|------|---------|-------------|
| -i | --input_file | file | required | Expression matrix in CSV or TSV format |
| -o | --output_dir | dir | ./output | Output directory |
| -m | --method | string | log2 | Normalization method: log2, zscore, minmax |
| -r | --margin | string | column | Apply normalization by row or column |
| -p | --pseudo_count | numeric | 1 | Added before log2 transformation |
| -c | --center | boolean | true | Center values for z-score |
| -s | --scale_values | boolean | true | Scale values for z-score |
| -t | --timeout_seconds | integer | 0 | Optional timeout; 0 disables it |
| -d | --delimiter | string | auto | Input delimiter: auto, csv, or tsv |
| | --seed | integer | 42 | Random seed |
| | --verbose | boolean | true | Print progress logs |
Input Format
The first column must contain feature identifiers. Remaining columns must be finite numeric sample values.
Missing values and non-finite values such as NA, NaN, Inf, and -Inf are rejected.
feature,S1,S2,S3
TP53,10,20,30
EGFR,3,5,9
This skill accepts gene or protein expression matrices. It does not infer count-model normalization such as CPM, TPM, TMM, or DESeq2 size factors.
Output Files
If --output_dir already exists, result files with the same names are overwritten. When --verbose=true, the workflow prints a warning before writing into a non-empty output directory.
For single-sample inputs, feature_summary.csv reports per-feature standard deviations as 0 by design because each feature contributes one observed value.
| File | Description |
|------|-------------|
| table/normalized_matrix.csv | Normalized matrix with the original feature column preserved |
| table/feature_summary.csv | Per-feature min, max, mean, and SD before and after normalization |
| table/sample_summary.csv | Per-sample min, max, mean, and SD before and after normalization |
| data/normalized_matrix.rds | Serialized normalized matrix and run metadata |
| run_record.txt | Structured execution record |
| output_manifest.txt | Output file manifest |
| session_info.txt | R session information |
Methods
log2
Computes log2(x + pseudo_count) for each numeric value.
zscore
Centers and scales along the selected margin. margin=column standardizes each sample; margin=row standardizes each feature.
When center=false and scale_values=true, the workflow divides by standard deviation without subtracting the mean first.
minmax
Rescales values to [0, 1] along the selected margin. Constant vectors are returned as zeros to avoid division-by-zero errors.
Error Handling
| Error | Cause | Solution |
|-------|-------|----------|
| SKILL_FILE_NOT_FOUND | Input file path is invalid | Check the input path |
| SKILL_MISSING_COLUMNS | Matrix has fewer than two columns | Provide one feature column and at least one sample column |
| SKILL_INVALID_PARAMETER | CLI value is unsupported or malformed, or the matrix contains non-finite values | Review the argument table and inspect the matrix values |
| SKILL_TIMEOUT | The run exceeded --timeout_seconds | Increase the timeout or simplify the input size |
| SKILL_EMPTY_DATA | No usable rows or columns remain | Check the input matrix |
Testing
Rscript scripts/main.R --help
Rscript tests/run_tests.R
Rscript tests/run_tests.R audit_output_check
Rscript tests/test_skill.R
Rscript tests/test_skill.R audit_output_check --skip-prepare
tests/run_tests.R executes bundled log2, zscore, and minmax runs and writes their outputs under tests/output/.
When you pass a relative directory name such as audit_output_check, the test runner writes outputs under tests/output/audit_output_check/.
Run tests/run_tests.R before tests/test_skill.R when you want to validate pre-generated outputs explicitly. The validation script can also prepare missing outputs on its own.
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