Merge branch 'fix-nufft-highlyperturbed' into development

ralfHielscher · Feb 5, 2018 · 475af62 · 475af62
2 parents cc6d73a + 5933bc6
commit 475af62
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Showing 2 changed files with 21 additions and 2 deletions.
diff --git a/@chebfun/nufft.m b/@chebfun/nufft.m
@@ -75,10 +75,11 @@
 [u, v] = constructAK(omega/N, (0:N-1)', K);
 
     function pc = p(c)
+        I = speye(numel(c));
         cK = repmat(c,1,K);
         tmp1 = conj(cK.*u);
-        tmp1 = tmp1(t,:);
-        tmp2 = conj( ifft( tmp1, [], 1) );
+        tmp1 = full(I(:,t)*tmp1);
+        tmp2 = conj(ifft( tmp1, [], 1));
         pc = N*sum(v.*tmp2, 2);
     end
 

diff --git a/tests/misc/test_nufft.m b/tests/misc/test_nufft.m
@@ -20,6 +20,15 @@
     count = count + 1;
 end
 
+% Test on random inputs: 
+N = 50; 
+omega = N*randn(1,N);
+c = rand(N,1) + 1i*rand(N,1);
+F = exp(-2*pi*1i*((0:N-1)/N).'*omega);
+f = chebfun.nufft(c, omega.', 1);
+pass(count) = ( norm( f - F*c ) < 300*N*tol*norm(c,1) );
+count = count + 1; 
+
 % Test NUFFT-II:
 for N = 10.^(0:4)
     x = linspace(0,1,N+1)'; x(end) = [];
@@ -31,6 +40,15 @@
     count = count + 1; 
 end
 
+% Test on random inputs: 
+N = 50; 
+x = 100*rand(N,1);
+c = rand(N,1) + 1i*rand(N,1);
+F = exp(-2*pi*1i*x*(0:N-1));
+f = chebfun.nufft(c, x);
+pass(count) = ( norm( f - F*c ) < 300*N*tol*norm(c,1) );
+count = count + 1; 
+
 % Test NUFFT-III
 for N = 10.^(0:4)
     omega = (0:N-1)';