From 6ca76797cb4034a961166ae782db550ba9a7e6e6 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Thu, 16 May 2019 14:08:27 +0200
Subject: transfer: implement fw4

---
 transfer.c | 5 +++++
 transfer.h | 1 +
 2 files changed, 6 insertions(+)

diff --git a/transfer.c b/transfer.c
index 40acd0a..6db1ad2 100644
--- a/transfer.c
+++ b/transfer.c
@@ -264,6 +264,7 @@ static const GridTransfer transfer_lagrange = {
 static const double fw_factors_1[] = { 0.5, 1.0, 0.5 };
 static const double fw_factors_2[] = { -1.0 / 16, 9.0 / 16, 1.0, 9.0 / 16, -1.0 / 16 };
 static const double fw_factors_3[] = { 3.0 / 256, -25.0 / 256, 75.0 / 128, 1.0, 75.0 / 128, -25.0 / 256, 3.0 / 256 };
+static const double fw_factors_4[] = { -5.0 / 2048, 49.0 / 2048, -245.0 / 2048, 1225.0 / 2048, 1.0, 1225.0 / 2048, -245.0 / 2048, 49.0 / 2048, -5.0 / 2048 };
 
 typedef struct GridTransferFW {
     ptrdiff_t order;
@@ -343,6 +344,10 @@ static int transfer_fw_init(GridTransferContext *ctx)
         fw->order   = 3;
         fw->factors = fw_factors_3;
         break;
+    case GRID_TRANSFER_FW_4:
+        fw->order   = 4;
+        fw->factors = fw_factors_4;
+        break;
     default:
         return -EINVAL;
     }
diff --git a/transfer.h b/transfer.h
index d000dcd..0a10f3a 100644
--- a/transfer.h
+++ b/transfer.h
@@ -32,6 +32,7 @@ enum GridTransferOperator {
     GRID_TRANSFER_FW_1,
     GRID_TRANSFER_FW_2,
     GRID_TRANSFER_FW_3,
+    GRID_TRANSFER_FW_4,
 };
 
 /**
-- 
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