// Licensed under the Apache License, Version 2.0
// © mihakralj
//@version=6
indicator("Logarithmic Transformation (LOG)", "Logtrans", overlay=false)

//@function Applies a natural logarithmic transformation (y = ln(x)) to the input series.
//@param source series float The input series to transform. Must contain positive values.
//@returns series float The logarithmically transformed series. Returns na if source <= 0.
//@optimized for performance and dirty data
logT(series float source) =>
    if na(source)
        na
    else if source <= 0
        na
    else
        math.log(source)

// ---------- Main loop ----------

// Inputs
i_source = input.source(close, "Source")

// Calculation
transformedSource = logT(i_source)

// Plot
plot(transformedSource, "Logtrans", color=color.yellow, linewidth=2)