[PATCH] Planner: simplify enough_gas comparison

[Rick Walsh]

The enough_gas function is used in recreational mode to determine that the
reserve gas is kept in reserve.  A simple comparison of end pressure => reserve
pressure should suffice.

The existing/previous comparison includes deco_gas_used, double-counting the gas
used in the ascent/safety stop.

Signed-off-by: Rick Walsh <rickmwalsh at gmail.com>
---

As an example to check this, plan a dive to 15 m with EAN32 in a 12 l tank with working pressure 232 bar.  Set reserve gas to 50 bar.  SAC of 20 l/min.  NDL is ~135 minutes with GF 60/80, so gas consumption will govern.  Bottom time is 38 min, giving a total dive of 43 min including a 3 minute safety stop and ascent at 9 m/min.  End cylinder pressure is 63 bar.  2033 l is used (169 bar), including 149 l (12 bar) on ascent.

With this simple patch, for this example the bottom time is extended an extra 3 minutes, and the ending pressure is 50 bar.  2183 l (182 bar) is used, including 149 l (12 bar) on ascent.

Robert, can you please check I'm not overlooking something?


 planner.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/planner.c b/planner.c
index 05fd26e..26a6c44 100644
--- a/planner.c
+++ b/planner.c
@@ -946,7 +946,7 @@ bool enough_gas(int current_cylinder)
 	if (!cyl->start.mbar)
 		return true;
 	if (cyl->type.size.mliter)
-		return (float) (cyl->end.mbar - prefs.reserve_gas)	 * cyl->type.size.mliter / 1000.0 > (float) cyl->deco_gas_used.mliter;
+		return cyl->end.mbar >= prefs.reserve_gas;
 	else
 		return true;
 }
-- 
2.4.3