http://www.k-wave.org/forum/topic/wave-vector Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:05:26 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/wave-vector#post-111 Mon, 14 Mar 2011 11:11:33 +0000 bencox 111@http://www.k-wave.org/forum/ <p>Hi Jeremy,</p> <p>Please can you be a bit more specific about what it is you don't understand. Is it that there are two slightly different uses of the word 'vector' here?</p> <p>kx and ky are vectors in the Matlab sense of 'vector' meaning a list of numbers. They contain a discretised version of the wavenumber components in the x and y directions of the wavevector (kx,ky), where wavevector here means 'vector' in the mathematical sense meaning a quantity with direction and magnitude. k is the magnitude of the wavevector (kx,ky).</p> <p>The relationship between the discretised spatial coordinates (x,y) and the discretised wavenumber components (the coordinates in wavenumber space) (kx,ky) is fixed by the requirements of the Fast Fourier Transform.</p> <p>Hope that helps,</p> <p>Ben </p> http://www.k-wave.org/forum/topic/wave-vector#post-110 Sat, 12 Mar 2011 19:17:57 +0000 jeremyk 110@http://www.k-wave.org/forum/ <p>Hi Ben,</p> <p>This may be a stupid question, but in one over your papers you define the wave vector<br /> as </p> <p>nx=(-Nx/2:Nx/2-1)';<br /> ny=(-Ny/2:Ny/2-1)';</p> <p>[x,y]=meshgrid(nx*dx,ny*dy);<br /> [kx,ky]=meshgrid(nx*2*pi/(Nx*dx),ny*2*pi/(Ny*dy));</p> <p>k=sqrt(kx.^2+ky.^2); </p> <p>can you explain why you did this? i don't quite understand how it works.</p> <p>thank you, jeremy </p>