Matlab Coder fails generation for slerp() call with double quaternions

Question

Kunal Patel 2020-10-30

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/631739-matlab-coder-fails-generation-for-slerp-call-with-double-quaternions

评论： Kunal Patel 2020-11-9

I am using MATLAB coder to generate code for following function.

function [D] = getInterpolatedTransforms(q0,t0,q1,t1,steps,correction)
D = zeros(4,4,steps);    
for i = 0:1:steps-1
    coeff = single(i/steps);
    qt = slerp(q0,q1,coeff);
    tt = [t0*(1-coeff)+t1*coeff,1]';
    D(1:3,1:3,i+1) = (quat2rotm(qt))*correction;
    D(1:4,4,i+1) = tt;
    
end
end

I get following error while generating code at the "check for issues" step

??? This assignment writes a 'single' value into a 'double' type. Code generation does
not support changing types through assignment. Check preceding assignments or input
type specifications for type mismatches.
Error in ==>> quaternioncg Line: 48 Column: 17
Code generation failed: View Error Report
 
??? This assignment writes a 'single' value into a 'double' type. Code generation does
not support changing types through assignment. Check preceding assignments or input
type specifications for type mismatches.
Error in ==>> quaternioncg Line: 48 Column: 17
Code generation failed: View Error Report

The location of the error is in Matlab internal file quaternioncg.m

Please help me reolve the issue. I am new to this tool.

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James Tursa 2020-11-2

在 MATLAB Online 中打开

Maybe you could tell us which line is generating the error?

Could you use double types instead? E.g.,

coeff = double(i/steps);

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Answer 1

Darshan Ramakant Bhat 2020-11-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/631739-matlab-coder-fails-generation-for-slerp-call-with-double-quaternions#answer_531059

在 MATLAB Online 中打开

Solution 1 : Remove the single cast

function [D] = getInterpolatedTransforms(q0,t0,q1,t1,steps,correction)
D = zeros(4,4,steps);    
for i = 0:1:steps-1
    coeff = i/steps;
    qt = slerp(q0,q1,coeff);
    tt = [t0*(1-coeff)+t1*coeff,1]';
    D(1:3,1:3,i+1) = (quat2rotm(qt))*correction;
    D(1:4,4,i+1) = tt;
    
end
end

Solution 2: Make the input quaternion as single

>> a = quaternion(single([45,0,0]),'eulerd','ZYX','frame');
>> c = quaternion(single([-45,0,0]),'eulerd','ZYX','frame');
>> codegen getInterpolatedTransforms -args {a,1:3,c,3:5,10,0.5} -report