Use position_price to compute size_usd in open_position

Author: askibin

programs/perpetuals/src/instructions/get_entry_price_and_fee.rs

@@ -92,12 +92,6 @@ pub fn get_entry_price_and_fee(
         custody.pricing.use_ema,
     )?;
 
-    let max_price = if token_price > token_ema_price {
-        token_price
-    } else {
-        token_ema_price
-    };
-
     let collateral_token_price = OraclePrice::new_from_oracle(
         &ctx.accounts
             .collateral_custody_oracle_account
@@ -121,7 +115,11 @@ pub fn get_entry_price_and_fee(
 
     let entry_price = pool.get_entry_price(&token_price, &token_ema_price, params.side, custody)?;
 
-    let size_usd = max_price.get_asset_amount_usd(params.size, custody.decimals)?;
+    let position_oracle_price = OraclePrice {
+        price: entry_price,
+        exponent: -(Perpetuals::PRICE_DECIMALS as i32),
+    };
+    let size_usd = position_oracle_price.get_asset_amount_usd(params.size, custody.decimals)?;
     let collateral_usd = min_collateral_price
         .get_asset_amount_usd(params.collateral, collateral_custody.decimals)?;
 

programs/perpetuals/src/instructions/open_position.rs

@@ -163,12 +163,6 @@ pub fn open_position(ctx: Context<OpenPosition>, params: &OpenPositionParams) ->
         custody.pricing.use_ema,
     )?;
 
-    let max_price = if token_price > token_ema_price {
-        token_price
-    } else {
-        token_ema_price
-    };
-
     let collateral_token_price = OraclePrice::new_from_oracle(
         &ctx.accounts
             .collateral_custody_oracle_account
@@ -209,7 +203,11 @@ pub fn open_position(ctx: Context<OpenPosition>, params: &OpenPositionParams) ->
     }
 
     // compute position parameters
-    let size_usd = max_price.get_asset_amount_usd(params.size, custody.decimals)?;
+    let position_oracle_price = OraclePrice {
+        price: position_price,
+        exponent: -(Perpetuals::PRICE_DECIMALS as i32),
+    };
+    let size_usd = position_oracle_price.get_asset_amount_usd(params.size, custody.decimals)?;
     let collateral_usd = min_collateral_price
         .get_asset_amount_usd(params.collateral, collateral_custody.decimals)?;
 

programs/perpetuals/tests/anchor/basic.ts

@@ -482,7 +482,7 @@ describe("perpetuals", () => {
       updateTime: "0",
       side: { long: {} },
       price: "124230000",
-      sizeUsd: "861000000",
+      sizeUsd: "869610000",
       collateralUsd: "123000000",
       unrealizedProfitUsd: "0",
       unrealizedLossUsd: "0",

programs/perpetuals/tests/native/tests_suite/position/liquidate_position.rs

@@ -185,7 +185,7 @@ pub async fn liquidate_position() {
 
         assert_eq!(
             martin_eth_balance,
-            utils::scale_f64(1.376624036, ETH_DECIMALS)
+            utils::scale_f64(1.369834721, ETH_DECIMALS)
         );
     }
 }