From b7e0433169474656f3027a3c114517d9839baa63 Mon Sep 17 00:00:00 2001
From: Hai Zhu <zhuh1106@gmail.com>
Date: Fri, 18 Oct 2024 22:18:13 -0700
Subject: [PATCH] clean up stokes slp kernel split

---
 chunkie/@kernel/stok2d.m              | 20 ++++++++++++--------
 devtools/test/chunkermat_stok2dTest.m |  2 +-
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/chunkie/@kernel/stok2d.m b/chunkie/@kernel/stok2d.m
index 91ae858..b5bb102 100644
--- a/chunkie/@kernel/stok2d.m
+++ b/chunkie/@kernel/stok2d.m
@@ -195,20 +195,24 @@
 
 function f = stok2d_s_split(mu,s,t)
 dist = (s.r(1,:)+1i*s.r(2,:))-(t.r(1,:)'+1i*t.r(2,:)');
+distr = real(dist);
+disti = imag(dist);
 f = cell(3, 1);
 ntarg = numel(t.r(1,:));
 nsrc = numel(s.r(1,:));
+sn1mat = repmat(s.n(1,:),[ntarg 1]);
+sn2mat = repmat(s.n(2,:),[ntarg 1]);
 f{1} = zeros(2*ntarg,2*nsrc);
 f{2} = zeros(2*ntarg,2*nsrc);
 f{3} = zeros(2*ntarg,2*nsrc);
 f{1}(1:2:end,1:2:end) = 1/(2*mu);
 f{1}(2:2:end,2:2:end) = 1/(2*mu);
-f{2}(1:2:end,1:2:end) = (-(repmat(s.n(1,:),[ntarg 1]))).*real(dist)/(2*mu);     
-f{2}(1:2:end,2:2:end) = -((repmat(s.n(2,:),[ntarg 1]))).*real(dist)/(2*mu);
-f{2}(2:2:end,1:2:end) = (-(repmat(s.n(1,:),[ntarg 1]))).*imag(dist)/(2*mu); 
-f{2}(2:2:end,2:2:end) = -((repmat(s.n(2,:),[ntarg 1]))).*imag(dist)/(2*mu);
-f{3}(1:2:end,1:2:end) = - (repmat(s.n(2,:),[ntarg 1])).*real(dist)/(2*mu);
-f{3}(1:2:end,2:2:end) =   (repmat(s.n(1,:),[ntarg 1])).*real(dist)/(2*mu);
-f{3}(2:2:end,1:2:end) = - (repmat(s.n(2,:),[ntarg 1])).*imag(dist)/(2*mu);
-f{3}(2:2:end,2:2:end) =   (repmat(s.n(1,:),[ntarg 1])).*imag(dist)/(2*mu);
+f{2}(1:2:end,1:2:end) = -sn1mat.*distr/(2*mu);     
+f{2}(1:2:end,2:2:end) = -sn2mat.*distr/(2*mu);
+f{2}(2:2:end,1:2:end) = -sn1mat.*disti/(2*mu); 
+f{2}(2:2:end,2:2:end) = -sn2mat.*disti/(2*mu);
+f{3}(1:2:end,1:2:end) = -sn2mat.*distr/(2*mu);
+f{3}(1:2:end,2:2:end) =  sn1mat.*distr/(2*mu);
+f{3}(2:2:end,1:2:end) = -sn2mat.*disti/(2*mu);
+f{3}(2:2:end,2:2:end) =  sn1mat.*disti/(2*mu);
 end
diff --git a/devtools/test/chunkermat_stok2dTest.m b/devtools/test/chunkermat_stok2dTest.m
index 6e22f47..0d1b2ed 100644
--- a/devtools/test/chunkermat_stok2dTest.m
+++ b/devtools/test/chunkermat_stok2dTest.m
@@ -94,7 +94,7 @@
 t1 = toc(start);
 fprintf('%5.2e s : time to eval at targs (slow, adaptive routine)\n',t1)
 
-% test stokes slp velocity pquad...
+% just test stokes slp velocity pquad...
 % targets = targets.*repmat(rand(1,nt),2,1)*0.99 seems to break below stokes kernel test...
 fkerns = kernel('stok', 'svel', mu);
 Ssol = chunkerkerneval(chnkr,fkerns,sol,targets,opts);