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

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.

[James Tursa]

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

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

coeff = double(i/steps);

Answer 1

[Darshan Ramakant Bhat]

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

[Kunal Patel]

Thank you, This worked.