Hi, I was trying to work through this example on the k-Wave website: http://www.k-wave.org/documentation/example_us_defining_transducer.php but am having issues replicating their results. The code I used is:
% create the computational grid
Nx = 128; % number of grid points in the x (row) direction
Ny = 128; % number of grid points in the y (column) direction
Nz = 128;
dx = 0.1e-3; % grid point spacing in the x direction [m]
dy = 0.1e-3; % grid point spacing in the y direction [m]
dz = 0.1e-3; % grid point spacing in the z direction [m]
kgrid = kWaveGrid(Nx, dx, Ny, dy, Nz,dz);
% define the properties of the propagation medium
medium.sound_speed = 1500 * ones(Nx, Ny); % [m/s]
medium.sound_speed(1:Nx/2, :) = 1800; % [m/s]
medium.density = 1000 * ones(Nx, Ny); % [kg/m^3]
medium.density(:, Ny/4:Ny) = 1200; % [kg/m^3]
kgrid.makeTime(medium.sound_speed)
% define properties of the input signal
source_strength = 1e6; % [MPa]
tone_burst_freq = 0.5e6; % [Hz]
tone_burst_cycles = 5;
% create the input signal using toneBurst
input_signal = toneBurst(1/kgrid.dt, tone_burst_freq, tone_burst_cycles);
% scale the source magnitude by the source_strength divided by the
% impedance (the source is assigned to the particle velocity)
input_signal = (source_strength ./ (medium.sound_speed * medium.density)).* input_signal;
% physical properties of the transducer
transducer.number_elements = 72; % total number of transducer elements
transducer.element_width = 1; % width of each element [grid points]
transducer.element_length = 12; % length of each element [grid points]
transducer.element_spacing = 0; % spacing (kerf width) between the elements [grid points]
transducer.radius = inf; % radius of curvature of the transducer [m]
% calculate the width of the transducer in grid points
transducer_width = transducer.number_elements * transducer.element_width + (transducer.number_elements - 1) * transducer.element_spacing;
% use this to position the transducer in the middle of the computational grid
transducer.position = round([1, Ny/2 - transducer_width/2, Nz/2 - transducer.element_length/2]);
% properties used to derive the beamforming delays
transducer.sound_speed = 1540; % sound speed [m/s]
transducer.focus_distance = 20e-3; % focus distance [m]
transducer.elevation_focus_distance = 19e-3; % focus distance in the elevation plane [m]
transducer.steering_angle = 0; % steering angle [degrees]
% apodization
transducer.transmit_apodization = 'Rectangular';
transducer.receive_apodization = 'Rectangular';
% define the transducer elements that are currently active
transducer.active_elements = zeros(transducer.number_elements, 1);
transducer.active_elements(21:52) = 1;
% append input signal used to drive the transducer
transducer.input_signal = input_signal;
% create the transducer using the defined settings
transducer = kWaveTransducer(kgrid, transducer);
% create a sensor mask covering the entire computational domain using the
% opposing corners of a rectangle
sensor.mask = [1, 1, Nx, Ny].';
% set the record mode to capture the final wave-field and the statistics at
% each sensor point
sensor.record = {'p_final', 'p_max', 'p_rms'};
% run the simulation
[sensor_data] = kspaceFirstOrder3D(kgrid, medium, transducer, sensor, input_args{:});But I get the following error:
Arrays have incompatible sizes for this operation.
Error in DefiningAnUltrasoundTransducerExample (line 28)
input_signal = (source_strength ./ (medium.sound_speed * medium.density)).* input_signal;In the example, the computational grid and medium properties are not shown so I used the values shown in other examples in the same section so I assume my issue is related to something the top sections. Thanks in advance for any help.