k-Wave User Forum » Topic: Multiple Sources in 3-Dimensional Space

k-Wave User Forum » Topic: Multiple Sources in 3-Dimensional Space http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 20:27:06 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php lbruju on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6431 Fri, 20 Apr 2018 14:01:09 +0000 lbruju 6431@http://www.k-wave.org/forum/ Hi, I am not sure of my simulation yet, but thanks for the information. lbruju Bradley Treeby on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6428 Thu, 19 Apr 2018 08:48:11 +0000 Bradley Treeby 6428@http://www.k-wave.org/forum/ Hi lbruju, I'm not sure of your input conditions, but getting a focal pressure of 60 MPa with an input pressure of 10 Pa implies a focal gain of 6 million, which seems much too high. The value after scaling seems more plausible, at least to me. Brad. lbruju on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6427 Thu, 19 Apr 2018 08:35:32 +0000 lbruju 6427@http://www.k-wave.org/forum/ Hi Bradley, Thanks a lot, I haven't noticed that. But I am confused regarding the final pressure values obtained when using this source scaling term. I add: <code>source_scaling_term=(2*dt)/(3*1500*dx)</code> which is around 7.4E-8. The <code>p_source_input</code> is a sinus with an amplitude of 10Pa, so the simulation should give the pressure field in Pa too. Without the source scaling term, I obtained a pressure of 6.33E7 at the focal point, which seems to be correct. But with the source scaling term, I have only 4.8 (which corresponds to <code>6.33E7*source_scaling_term</code> ). Thanks, lbruju Bradley Treeby on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6426 Wed, 18 Apr 2018 14:05:36 +0000 Bradley Treeby 6426@http://www.k-wave.org/forum/ Great! One other point, if you're manually creating the input file, you will need to apply to source scaling term. See Line 208 in the <code>example_cpp_io_in_parts.m</code> (you don't need MATLAB to see the code). Brad. lbruju on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6425 Wed, 18 Apr 2018 12:24:55 +0000 lbruju 6425@http://www.k-wave.org/forum/ Hi, I have finally found the error! The matrix <code>p_source_input</code> should be transposed. The correct shape is <code>Nt x np.size(p_source_index)</code> and not the opposite as I generated before. Thanks, lbruju lbruju on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6424 Wed, 18 Apr 2018 10:46:37 +0000 lbruju 6424@http://www.k-wave.org/forum/ Hi Bradley, Thanks for your answer. I have checked the values, and they seem to be the same. In the first case I have: P_SOURCE_INDEX: <code>p_source_index0=np.array[[3363674]] #only one point for the top of the spherical cap</code> <code>p_source_index1=np.array[[3273700,3274150,3274749,...]] #index of points on the 1st ring</code> ETC... until <code>p_source_index7=np.array[[2891235,2891684,2892284,...]] #index of points on the 7th ring</code> P_SOURCE_INPUT: <code>p_source_input0=sig0 #where sig0 is a list of size (1,Nt)</code> <code>p_source_input1=sig1 #where sig1 is a list of size (1,Nt)</code> ETC... until <code>p_source_input7=sig7 #where sig7 is a list of size (1,Nt)</code> And in the second case I have: P_SOURCE_INDEX: <code>p_source_index=np.array[[3363674,3273700,3274150,3274749,...,2891235,2891684,2892284,...]] #index of all the points</code> P_SOURCE_INPUT: <code>p_source_input</code> is a matrix of size <code>np.size(p_source_index) x Nt</code> where: <code>p_source_input[0,:]=sig0</code> <code>p_source_input[1:np.size(p_source_index1),:]=sig1</code> ETC... until the last one. Did I well understand that the the first line in <code>p_source_input</code> will be the signal attributed to the first index in <code>p_source_index</code> and so on? Thanks a lot for your help and for taking time to answer. lbruju Bradley Treeby on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6423 Wed, 18 Apr 2018 09:25:53 +0000 Bradley Treeby 6423@http://www.k-wave.org/forum/ Hi lbruju, Nope, provided your simulation is linear, they should give the same results. Perhaps it's an error in the indexing in the second case? Brad. lbruju on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6416 Tue, 17 Apr 2018 08:35:51 +0000 lbruju 6416@http://www.k-wave.org/forum/ Hi, I am trying to simulate the pressure field generated by 8 rings defined on a spherical cap. All the points on a same ring have the same <code>p_source_input</code> signal, but each ring has a different signal. I made the simulation by two different ways. 1) I simulate the pressure field generated by one ring after the other. I put <code>p_source_many=0</code>. kspaceFirstOrder3DGC-OMP.exe is executed for each ring and I sum the results (with a sensor_mask which contains all the points of the FOV). 2) I simulate the pressure field generated by all the rings at the same time. I put <code>p_source_many=1</code>. kspaceFirstOrder3DGC-OMP.exe is executed only once. I don't understand why I don't obtain the same result with both simulations. The only difference is that all the inputs (index values and input signals) are separated in 16 different matrices (8 matrices for <code>p_source_index</code> and 8 for <code>p_source_input</code> ) in the first case. Whereas the inputs are separated in only 2 matrices (1 for <code>p_source_index</code> and one for <code>p_source_input</code> ) in the second case. Do you have an idea of where the error could come from? Thanks a lot, lbruju Bradley Treeby on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6397 Sun, 08 Apr 2018 18:52:11 +0000 Bradley Treeby 6397@http://www.k-wave.org/forum/ Hi char7114, It's not possible to define a different source mask for the different components of the velocity. A work around is to use a single <code>source.u_mask</code> that covers all of the sources. Then, for each component of the velocity, for the grid points that are not transmitting, set the source term to zero. Hope that helps, Brad. char7114 on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6375 Sun, 01 Apr 2018 00:27:21 +0000 char7114 6375@http://www.k-wave.org/forum/ Brad, I have worked through your user manual as well as the available examples and have managed to combine pressure and velocity sources in the same space whilst utilising the column wise indexing. Thank you for your help in this regard. I am however currently unable to combine velocity sources of different direction (.ux, .uy and .uz) into this space. Is this something which should be possible? I can only get the individual sources to all propagate in the same direction through specification of the source.u matrix which I am using to reference the sources to the desired mask location. Could this possibly be achieved by creating a second mask and incorporating it into the same space? Perhaps I am just defining my source matrix incorrectly. Again, thank you for your aid. Bradley Treeby on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6365 Wed, 21 Mar 2018 21:51:45 +0000 Bradley Treeby 6365@http://www.k-wave.org/forum/ Hi char7114, There are some details on the ordering of the inputs in the <a href="http://www.k-wave.org/documentation/example_tvsp_homogeneous_medium_monopole.php">Monopole Point Source In A Homogeneous Propagation Medium Example</a> (this is accessible from the MATLAB help browser), and also in the k-Wave manual. Hope that helps, Brad. char7114 on "Multiple Sources in 3-Dimensional Space" http://www.k-wave.org/forum/topic/multiple-sources-in-3-dimensional-space#post-6353 Tue, 20 Mar 2018 03:11:21 +0000 char7114 6353@http://www.k-wave.org/forum/ First and foremost, I would like to express my appreciation for the release of this package and its continued efforts. Most impressive. I am still wrapping my head around its functionality however I had a question in regards to creating a 3-Dimensional space with multiple di-pole and mono-pole sources. I have managed to incorporate multiple di-poles into the same space however I cannot seperate them into different locations in the grid and I cannot find a way to effectively combine mono-poles in the same space. Is there a simple way to add sources of different characteristics into different locations in the grid? My goal is to model the acoustics generated by a helicopter, which I believe will require velocity sources to represent the rotors and monopoles for the power plant and transmission. Each of these will be of different frequency and magnitude. I understand that the sources can be located by defining the location in the grid as a 1 in the matrix but am unsure how to specify an individual source to its own location. Many thanks.