Files
wickra/examples/r/_common.R
T
kingchenc 75eefbbd08 examples: fix and harmonize the strategy backtests across all languages (#324)
The strategy_* examples were only syntax-smoked in CI, never run, which hid two
classes of problem:

1. Python strategy_macd_adx / strategy_bollinger_squeeze passed three separate
   arguments to the candle indicators ADX/ATR, whose .update() takes a single
   candle — a TypeError at runtime — and read the ADX tuple at index 0 (plus_di)
   instead of 2 (adx). Both fixed.

2. The Go / C# / R / Java strategies defaulted to synthetic data and used a
   different (annualised) one-line summary, so they printed wildly different
   numbers from the Rust/Python/Node/C/WASM suite. Rewrite them to the shared
   per-trade backtest (load the bundled BTCUSDT CSV by default, same entry/exit
   logic, same print_summary output).

All nine runnable bindings now print byte-identical backtest summaries on the
same data (MACD+ADX 246 trades / -47.19%, RSI 37 / -17.84%, Bollinger 1 / -7.82%),
verified by diffing each language's output against the Python reference. WASM
shares the same logic and bundled dataset (browser-rendered).
2026-06-17 17:56:22 +02:00

92 lines
3.8 KiB
R

# Shared helpers for the offline Wickra R examples: deterministic synthetic
# market data, a small OHLCV CSV loader, and an equity-curve summary. Mirrors the
# helpers used by the C, C# and Go example suites.
synthetic_prices <- function(count, start = 100) {
i <- seq_len(count) - 1
start + 12 * sin(i * 0.05) + 5 * sin(i * 0.013) + i * 0.01
}
synthetic_candles <- function(count, start_ts = 0, step_ms = 3600000) {
prices <- synthetic_prices(count + 1)
k <- seq_len(count)
i <- k - 1
open <- prices[k]
close <- prices[k + 1]
data.frame(
open = open,
high = pmax(open, close) + 0.5 + abs(sin(i * 0.7)),
low = pmin(open, close) - 0.5 - abs(cos(i * 0.7)),
close = close,
volume = 1000 + 500 * (1 + sin(i * 0.1)),
timestamp = start_ts + i * step_ms
)
}
load_ohlcv_csv <- function(path) {
# Native CandleReader: header validation, BOM and field-whitespace tolerance.
# read() returns an (n x 6) matrix of open, high, low, close, volume, timestamp.
m <- read(CandleReader(paste(readLines(path, warn = FALSE), collapse = "\n")))
data.frame(open = m[, "open"], high = m[, "high"], low = m[, "low"],
close = m[, "close"], volume = m[, "volume"], timestamp = m[, "timestamp"])
}
summarize_equity <- function(returns, trades, periods_per_year = 252) {
equity <- 1; peak <- 1; maxdd <- 0
for (r in returns) {
equity <- equity * (1 + r)
peak <- max(peak, equity)
maxdd <- max(maxdd, (peak - equity) / peak)
}
mean_r <- if (length(returns)) mean(returns) else 0
sd_r <- if (length(returns) > 1) stats::sd(returns) else 0
sharpe <- if (sd_r > 1e-12) mean_r / sd_r * sqrt(periods_per_year) else 0
list(total_return_pct = (equity - 1) * 100, sharpe = sharpe,
max_dd_pct = maxdd * 100, trades = trades)
}
print_equity <- function(name, r) {
cat(sprintf("%-26s return=%8.2f%% sharpe=%6.2f maxDD=%6.2f%% trades=%d\n",
name, r$total_return_pct, r$sharpe, r$max_dd_pct, r$trades))
}
# Loads one of the checked-in datasets under examples/data (the R examples run
# from this directory, so ../data is examples/data).
bundled_candles <- function(filename) {
load_ohlcv_csv(file.path("..", "data", filename))
}
# Prints the per-trade backtest summary shared verbatim with the Rust, Python,
# Node, Go, C and C# example suites (same labels, same numbers).
print_summary <- function(name, first_price, last_price, bars, closed_trades, final_equity, equity_curve) {
buy_hold <- last_price / first_price
strat_return <- final_equity - 1
bh_return <- buy_hold - 1
n <- length(closed_trades)
wins <- sum(closed_trades > 0)
losses <- sum(closed_trades < 0)
best <- if (n > 0) max(closed_trades) else 0
worst <- if (n > 0) min(closed_trades) else 0
mean_r <- if (n > 0) mean(closed_trades) else 0
var_r <- if (n > 1) stats::var(closed_trades) else 0
sharpe <- if (var_r > 0) mean_r / sqrt(var_r) else 0
peak <- if (length(equity_curve) > 0) equity_curve[1] else 1
maxdd <- 0
for (eq in equity_curve) {
if (eq > peak) peak <- eq
dd <- (peak - eq) / peak
if (dd > maxdd) maxdd <- dd
}
cat(sprintf("=== %s ===\n", name))
cat(sprintf("%-23s%d\n", "Bars:", bars))
cat(sprintf("%-23s%d (W%d / L%d)\n", "Trades:", n, wins, losses))
cat(sprintf("%-23s%+.2f%%\n", "Strategy return:", strat_return * 100))
cat(sprintf("%-23s%+.2f%%\n", "Buy & Hold return:", bh_return * 100))
cat(sprintf("%-23s%+.2f%%\n", "Excess over BH:", (strat_return - bh_return) * 100))
cat(sprintf("%-23s%.2f%%\n", "Max drawdown:", maxdd * 100))
cat(sprintf("%-23s%.2f (mean %+.4f, stddev %.4f)\n", "Per-trade Sharpe:", sharpe, mean_r, sqrt(var_r)))
cat(sprintf("%-23s%+.2f%% / %+.2f%%\n", "Best / worst trade:", best * 100, worst * 100))
cat("\n")
cat("NOTE: Educational example — fees, slippage, funding costs and tax effects are simplified or omitted. Past performance is not indicative of future results.\n")
}