Does GPU coder have only one output?

Question

lim daehee 2019-11-22

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/492565-does-gpu-coder-have-only-one-output

编辑： lim daehee 2019-11-27

采纳的回答： Pravin Jagtap

I'm changing a function into mex file with GPU coder, and I have a problem while I using the GPU coder.

I want to get two matrices; D, N as the output of fcn_DH.

When I executed GPU coder with a code below, Running test file with MEX is not terminated, thus I cannot make MEX file.

However, When I changed the first line of the function into 'D = fcn_PRM(node,PosMap)', which has only one output, the GPU coder worked fine.

I'm wondering if I can apply the GPU coder to a function and only get one variable as a result.

Otherwise, if GPU coder can multiple outputs, I want to know which part of my code is wrong.

function [D,N] = fcn_PRM(node,PosMap)
n = length(node);
D = coder.nullcopy(zeros(n,n,2));
N = coder.nullcopy(zeros(n,n));
len=(1:n)';
pos_mat=PosMap(node(len),:);
coder.gpu.kernel;
for i=1:n-1
    for j=i+1:n
        dist=sqrt((pos_mat(i,1)-pos_mat(j,1))^2+(pos_mat(i,2)-pos_mat(j,2))^2+(pos_mat(i,3)-pos_mat(j,3))^2);
        B = collisionCheck_SP5(PosMap(node(i),:), PosMap(node(j),:));
        D(i,j,1) = dist;
        N(i,j) = B;
        
    end
end

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lim daehee 2019-11-25

编辑：lim daehee 2019-11-25

dlite_small.mat

Hello Parvin,

First of all, thank you for you reply and I'm sorry for my insufficient information.

Here is the code collisionCheck_SP5 and I attach the map file dlite_small.mat.

function B = collisionCheck_SP5(p1, p2)
P1=[round(p1(1)/0.3+1) round(p1(2)/0.3+1) round(p1(3)/0.3+1)];
P2=[round(p2(1)/0.3+1) round(p2(2)/0.3+1) round(p2(3)/0.3+1)];
chk_p=abs(P1-P2);
if (chk_p(1)>=chk_p(2)) && (chk_p(1)>=chk_p(3))
  
    if P1(1)<P2(1) 
        X=(P1(1):P2(1))';
    else 
        X=(P2(1):P1(1))';
    end
    
elseif (chk_p(2)>chk_p(1)) && (chk_p(2)>=chk_p(3))
    if P1(2)<P2(2)
        X=(P1(2):P2(2))';
    else
        X=(P2(2):P1(2))';
    end
    
else
    if P1(3)<P2(3)
        X=(P1(3):P2(3))';
    else
        X=(P2(3):P1(3))';
    end
end
% B=1;
B=size(X,1);

Also, I don't know what the caller MATLAB file means.. so I attach the main code which calls fcn_PRM.

clc
clear
close all
%% Map Load
load dlite_small.mat
%% Parameter Setting
NodeNum = 1000;
DrawCHK =1;
Vec{1} = unique(PosMap(:,1),'sorted');
Vec{2} = unique(PosMap(:,2),'sorted');
Vec{3} = unique(PosMap(:,3),'sorted');
%% Initialize condition
% WP Sett
num_goals=1:size(WP,1);         % Waypoint Num
com_goals=combnk(num_goals,2);  % Combination of route Num
WP_N = size(WP,1);
Obs_mat=make_obsmap(Map_Obs);
%% PRM
tic
% Initialization
idx_FS = find(Map_Obs == 1);
idx_temp=randperm(NodeNum)';
node_PRM = idx_FS(idx_temp);
[D,N] = fcn_PRM(node_PRM,PosMap);
MapGenTime=toc

Pravin Jagtap 2019-11-25

Hello Lim,

Refer to following documentation to understand GPU coder workflow:

https://www.mathworks.com/help/gpucoder/gs/gpu-code-generation-using-app.html

For code generation, we need to define 'primary' function which is 'fcn_PRM' in your case and 'entry-point function' which is used for the defining the input variables.

Still earlier issue persists since you are loading the data from ''dlite_small.mat'' which is not accessible to me. Also, please verify the code and provide all the necessary inputs for reproducing the error by executing the code.

lim daehee 2019-11-25

Hello Parvin,

Thank you for your continuous help.

In my case, the entry-point function is the main code, which starts with loading the dlite_small.mat file. I followed all procedures of GPU coder app on documentation you send to me. However, GPU coder app does not complete at a certain stage on attached figure.

Also, I don't understand why are you cannot accessible to "dlite_small.mat"file. I just confirmed that all files and codes are work well on my computer now. So I attach dlite_small.mat and all codes.

Thanks for your help.

Sincerely.

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Answer 1

Pravin Jagtap 2019-11-25

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/492565-does-gpu-coder-have-only-one-output#answer_403219

Hello Lim,

After analyzing the code, It is clear that you are not able to generate ‘MEX’ because the ‘%#codegen’ directive is missing in the function definition at beginning. To generate the ‘MEX’ please add the ‘%#codegen’ directive as shown below at the starting of the Entry-Point function:

function [D,N] = fcn_PRM(node_PRM,PosMap) %#codegen 
%…
%…
end

Also, make sure that the same function is getting called in the ‘Define Input Type’ stage.

Kind Regards

~Pravin

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Pravin Jagtap 2019-11-26

Hello Lim,

One of the possible reasons can be the data copy from Device to Host which can add extra overhead and the size of matrix is also considerable in your case. There can be other possible reasons as well.

~Pravin

lim daehee 2019-11-27

编辑：lim daehee 2019-11-27

Hello Parvin,

I always thanks to you for your help and I have a question about your reply.

Is the matrix size can cause the increase of calculation time?

The map data which I gave you is smaller one.. actual map size is 1701*1701*11 double and size of 'node' is 1900.

If my problem is caused by the size of the map data matrix, I want to know the maximum size of matrix that GPU coder can work properly.

Also, I know that GPU coder don't create kernel for indexing of matrix, is that right?

Plus, I realized that my problem is caused by data size of array N. The data size of N is 576kb. I wonder why the size of array cause the increase of calculation time.

Also, I wonder both maximum size of array and maximum data size of array that GPU coder can work properly.

Sincerely.

Lim.

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