From c55caaf79b257cbcbf514238cfe78edf141ac753 Mon Sep 17 00:00:00 2001
From: boris <shuaibo.zhang@hotmail.com>
Date: Sat, 29 Aug 2026 06:01:02 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BC=98=E5=8C=96=E7=AD=89=E4=BB=B7=E5=B8=82?=
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---
 .../fidc-core/src/platform_expr_strategy.rs   | 69 ++++++++++++++-----
 1 file changed, 51 insertions(+), 18 deletions(-)

diff --git a/crates/fidc-core/src/platform_expr_strategy.rs b/crates/fidc-core/src/platform_expr_strategy.rs
index 20fcabf..0b9a982 100644
--- a/crates/fidc-core/src/platform_expr_strategy.rs
+++ b/crates/fidc-core/src/platform_expr_strategy.rs
@@ -9219,6 +9219,15 @@ impl PlatformExprStrategy {
             .unwrap_or_else(|| self.field_value(candidate)))
     }
 
+    fn rank_reuses_market_cap_order(&self) -> bool {
+        self.config.rank_expr.trim().is_empty()
+            && !self.config.rank_desc
+            && matches!(
+                self.config.rank_by.trim(),
+                "market_cap" | "market_cap_bn"
+            )
+    }
+
     fn can_sell_position(&self, ctx: &StrategyContext<'_>, date: NaiveDate, symbol: &str) -> bool {
         self.can_sell_position_at_time(ctx, date, symbol, None)
     }
@@ -9429,24 +9438,26 @@ impl PlatformExprStrategy {
             }
             candidates.push((candidate, stock, rank_value));
         }
-        candidates.sort_by(|lhs, rhs| {
-            let lhs_value = lhs.2;
-            let rhs_value = rhs.2;
-            let ordering = if self.config.rank_desc {
-                rhs_value
-                    .partial_cmp(&lhs_value)
-                    .unwrap_or(std::cmp::Ordering::Equal)
-            } else {
-                lhs_value
-                    .partial_cmp(&rhs_value)
-                    .unwrap_or(std::cmp::Ordering::Equal)
-            };
-            if ordering == std::cmp::Ordering::Equal {
-                lhs.0.symbol.cmp(&rhs.0.symbol)
-            } else {
-                ordering
-            }
-        });
+        if !self.rank_reuses_market_cap_order() {
+            candidates.sort_by(|lhs, rhs| {
+                let lhs_value = lhs.2;
+                let rhs_value = rhs.2;
+                let ordering = if self.config.rank_desc {
+                    rhs_value
+                        .partial_cmp(&lhs_value)
+                        .unwrap_or(std::cmp::Ordering::Equal)
+                } else {
+                    lhs_value
+                        .partial_cmp(&rhs_value)
+                        .unwrap_or(std::cmp::Ordering::Equal)
+                };
+                if ordering == std::cmp::Ordering::Equal {
+                    lhs.0.symbol.cmp(&rhs.0.symbol)
+                } else {
+                    ordering
+                }
+            });
+        }
 
         let mut selected = Vec::new();
         for (candidate, stock, _) in candidates {
@@ -13749,6 +13760,28 @@ mod tests {
         );
     }
 
+    #[test]
+    fn market_cap_ascending_rank_reuses_only_equivalent_universe_order() {
+        let mut cfg = PlatformExprStrategyConfig::microcap_rotation();
+        cfg.rank_by = "market_cap".to_string();
+        let strategy = PlatformExprStrategy::new(cfg.clone());
+        assert!(strategy.rank_reuses_market_cap_order());
+
+        cfg.rank_by = "market_cap_bn".to_string();
+        assert!(PlatformExprStrategy::new(cfg.clone()).rank_reuses_market_cap_order());
+
+        cfg.rank_desc = true;
+        assert!(!PlatformExprStrategy::new(cfg.clone()).rank_reuses_market_cap_order());
+
+        cfg.rank_desc = false;
+        cfg.rank_expr = "close".to_string();
+        assert!(!PlatformExprStrategy::new(cfg.clone()).rank_reuses_market_cap_order());
+
+        cfg.rank_expr.clear();
+        cfg.rank_by = "free_float_cap".to_string();
+        assert!(!PlatformExprStrategy::new(cfg).rank_reuses_market_cap_order());
+    }
+
     #[test]
     fn current_rolling_helpers_do_not_load_factor_maps_or_decision_rollings() {
         let mut cfg = PlatformExprStrategyConfig::microcap_rotation();