Log2 Skew Transform
Apply a pseudocount log2 transform and measure dynamic-range compression.
Description
A log2 transform compresses signal range after adding a positive pseudocount.
A log2 transform compresses signal range after adding a positive pseudocount. Positivity applies to the shifted values rather than the raw signals.1
Apply a pseudocount log2 transform and measure dynamic-range compression.
When to use Log2 Skew Transform
Use this tool to apply a pseudocount log2 transform and measure dynamic-range compression.
Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.
How to use Log2 Skew Transform and understand its results
- Prepare the measured profile, formula counts, upstream model outputs or caller-defined reference criteria requested. Keep paired entries aligned and units, sample basis and preprocessing consistent.
- Enter signals, pseudocount using the field table and calculation rules, then run the tool.
- Read log2Signals, rawRange, transformedRange. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| signals | Signals | list of number | Required |
| pseudocount | Pseudocount | number | Required |
Enter nonempty finite signals and positive pseudocount, requiring every shifted signal>0. Return transformed values, original range and log range. Negative raw signals can be accepted.
transformed_i=log2(signal_i+pseudocount) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| log2Signals | Log 2 signals | list of number |
| rawRange | Raw range | number |
| transformedRange | Transformed range | number |
{
"input": {
"signals": [
0,
1,
3
],
"pseudocount": 1
},
"output": {
"log2Signals": [
0,
1,
2
],
"rawRange": 3,
"transformedRange": 2
}
}Limitations and assumptions
No statistical skewness estimate or fitted transformation parameter is provided.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Unit Variance Scaling: Autoscale a feature to zero mean and unit population variance. For a complementary task, use Pareto Scaling: Apply mean-centered Pareto scaling by the square root of standard deviation.
References
-
Log2 Skew Transform — tool.io
Similar or alternative tools
- Unit Variance Scaling
Autoscale a feature to zero mean and unit population variance.
- Pareto Scaling
Apply mean-centered Pareto scaling by the square root of standard deviation.