// Author: Simon-Pierre Boucher — contact@spboucher.ai
//
// One row of log.csv (RESEARCH.md §3). valLoss is nil when the CSV holds
// the -1 sentinel; elapsedS is nil for pre-elapsed_s runs (6-column header).
import Foundation

struct MetricPoint: Equatable, Sendable {
    var step: Int
    var trainLoss: Double
    var lr: Double
    var gradNorm: Double
    var tokensPerSec: Double
    var valLoss: Double?
    var elapsedS: Double?

    var tokensSeen: (Int) -> Int { { tokensPerStep in (step + 1) * tokensPerStep } }
    var perplexity: Double { exp(trainLoss) }
}