From 02c015bec8dc622ab782957fb87562259dd1be45 Mon Sep 17 00:00:00 2001
From: Nicolas Tessore <n.tessore@ucl.ac.uk>
Date: Mon, 17 Oct 2022 16:02:34 +0100
Subject: [PATCH] ENH: accurate transforms for l > 60_000

---
 dctdlt.c  | 10 +++++-----
 setup.cfg |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/dctdlt.c b/dctdlt.c
index 92fccc7..2177888 100644
--- a/dctdlt.c
+++ b/dctdlt.c
@@ -18,7 +18,7 @@
 //     Computing, 12(1), 158-179.
 //
 
-#define DCTDLT_VERSION 20220727L
+#define DCTDLT_VERSION 20221017L
 
 
 // dctdlt
@@ -51,7 +51,7 @@ void dctdlt(unsigned int n, unsigned int stride_in, const double* dct,
         *dlt = dct[0];
         for(j = 2; j < n; j += 2)
         {
-            b *= (j-3.)/(j+1.);
+            b *= (1 - 4./(j+1.));
             *dlt += b*dct[j*stride_in];
         }
     }
@@ -63,7 +63,7 @@ void dctdlt(unsigned int n, unsigned int stride_in, const double* dct,
         *dlt = b*dct[i*stride_in];
         for(j = i+2; j < n; j += 2)
         {
-            b *= (j*(j+i-2.)*(j-i-3.))/((j-2.)*(j+i+1.)*(j-i));
+            b *= (1. + 2./(j-2.)) * (1. - 3./(j+i+1.)) * (1. - 3./(j-i));
             *dlt += b*dct[j*stride_in];
         }
     }
@@ -100,7 +100,7 @@ void dltdct(unsigned int n, unsigned int stride_in, const double* dlt,
         *dct = dlt[0];
         for(j = 2; j < n; j += 2)
         {
-            b *= ((j-1.)*(j-1.))/(j*j);
+            b *= (1. - 1./j)*(1. - 1./j);
             *dct += b*dlt[j*stride_in];
         }
     }
@@ -112,7 +112,7 @@ void dltdct(unsigned int n, unsigned int stride_in, const double* dlt,
         *dct = b*dlt[i*stride_in];
         for(j = i+2; j < n; j += 2)
         {
-            b *= ((j-i-1.)*(j+i-1.))/((j-i)*(j+i));
+            b *= (1. - 1./(j-i)) * (1. - 1./(j+i));
             *dct += b*dlt[j*stride_in];
         }
     }
diff --git a/setup.cfg b/setup.cfg
index 7264f41..4acd312 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = flt
-version = 2022.7.27.1
+version = 2022.10.17
 maintainer = Nicolas Tessore
 maintainer_email = n.tessore@ucl.ac.uk
 description = fast Legendre transform