Parity probe 06 - 50% equity sizing

// This Pine Script® code is licensed under Apache-2.0
// SPDX-License-Identifier: Apache-2.0
// © PineForge contributors 2026
//
// Parity probe 06 — explicit qty at 50% of equity (moderate margin pressure)
//
// Purpose: bisect the margin-tolerance regime between parity-probe-03
// (100% equity, hits the boundary every entry, 31 engine extras vs TV)
// and parity-probe-05 (10% equity, no margin pressure expected).
//
// At 50% of equity, qty * fill_price ≈ 0.5 × equity at every entry —
// no slippage-driven margin overshoot is ever possible (next bar's
// open would have to ~double the prior close). If engine and TV
// AGREE on every Monday here too, then TV's "extra rejections" in
// probe-03 are SOLELY a strict-margin behavior at the 1× boundary
// and the engine's tolerance / scale-down policy is the only knob
// that needs adjustment to close the IES gap. If engine and TV
// DISAGREE here, there is some other equity / position-size rule
// in TV's broker emulator that we have not yet modeled, and probe-04
// (auto-sizing path) will tell us whether that rule is shared by
// the implicit-qty code path or unique to explicit qty.
//
// TV setup: 15m chart on BINANCE:ETHUSDT.P, same window as
// data/ohlcv_ETH-USDT-USDT_15m.csv. Export "List of Trades" to
// ``tv_trades.csv`` in this folder.
//@version=6
strategy("Parity probe 06 - 50% equity sizing", shorttitle="par_p06", overlay=true, initial_capital=1000000, commission_type=strategy.commission.percent, commission_value=0, slippage=0, default_qty_type=strategy.fixed, default_qty_value=1, pyramiding=0, process_orders_on_close=false)

// ---- engine -------------------------------------------------------
bool fire = dayofweek == 2 and hour == 0 and minute == 0 and strategy.position_size == 0

// qty encodes 50% of strategy.equity / close.
float qty_dyn = math.round(strategy.equity * 0.5 / close * 1000) / 1000

if fire and qty_dyn > 0
    strategy.entry("E", strategy.long, qty=qty_dyn, comment="qty = 50% equity / close")

if strategy.position_size > 0 and bar_index > strategy.opentrades.entry_bar_index(0)
    strategy.close("E", comment="next-bar flatten")