http://www.k-wave.org/forum/topic/the-size-of-kgridt_array-seems-error-which-is-produced-by-the-function-maketime Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 02:31:16 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/the-size-of-kgridt_array-seems-error-which-is-produced-by-the-function-maketime#post-8219 Wed, 16 Jun 2021 06:49:33 +0000 sins 8219@http://www.k-wave.org/forum/ <p>Thank you, Brad. I will try this function later. </p> http://www.k-wave.org/forum/topic/the-size-of-kgridt_array-seems-error-which-is-produced-by-the-function-maketime#post-8187 Tue, 08 Jun 2021 16:43:49 +0000 Bradley Treeby 8187@http://www.k-wave.org/forum/ <p>Hi Remy,</p> <p>There is a check in <code>kWaveGrid</code> for when <code>kgrid.dt</code> is a recurring number and thus the number of time steps (calculated by <code>floor(t_end / dt) + 1</code>) would be one number short. </p> <p>In your case, <code>t_end/dt</code> works out to be 5.000000000000001e+02 (i.e., there is an overflow in the last digit) and the same piece of code catches this and incorrectly adds 1 to the length of the time series.</p> <p>You can work around this by instead using <code>kgrid.setTime(Nt, dt)</code> to set the time array.</p> <p>I've raised an issue to look at this case for the possible fix in the future.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/the-size-of-kgridt_array-seems-error-which-is-produced-by-the-function-maketime#post-8146 Sat, 08 May 2021 08:10:46 +0000 sins 8146@http://www.k-wave.org/forum/ <p>Hi,<br /> When I use makeTime function to create a time series, the end of the time series seems out of range.<br /> I set t_end = 6e-5s, and dt = 1.2e-7s, the length of the time series should be 501 points. But I got the time series with a length of 502, and the kgrid.t_array ends up with 6.012e-5s. I don't know if this is related to "makeTime" function. My test code is listed below, thank you for your help.<br /> Version of MATLAB: R2020a<br /> Version of k-Wave: 1.3</p> <p>Best Regards,<br /> Remy.</p> <p>%%---------------------------<br /> clear all;<br /> % Define medium<br /> medium.sound_speed = 1500; % [m/s]<br /> medium.density = 1000;</p> <p>object_sim.Nx = 501; % number of grid points in the x (row) direction<br /> object_sim.Ny = 501; % number of grid points in the y (column) direction<br /> object_sim.x = 100.2e-3; % total grid size [m]<br /> object_sim.y = 100.2e-3; % total grid size [m]</p> <p>dx = object_sim.x/object_sim.Nx; % grid point spacing in the x direction [m]<br /> dy = object_sim.y/object_sim.Ny; % grid point spacing in the y direction [m]<br /> kgrid = makeGrid(object_sim.Nx, dx, object_sim.Ny, dy);<br /> % create time series<br /> cfl = 0.9; % speed*dt/min(dx,dy)<br /> t_end = 600e-7; % time(seconds)<br /> [kgrid.t_array,dt] = makeTime(kgrid, medium.sound_speed, cfl, t_end);<br /> time.dt = dt; % sampling time in sec 1.2e-7, 8.3333MHz<br /> time.length = length(kgrid.t_array); % number of points in time </p>