Loaded quaternion but still cannot find slerp

After installing the Sensor Fusion toolbox, Matlab reopens. I used the following code:

q1 = quaternion([75,-20,-10],"eulerd","ZYZ","frame");

q2 = quaternion([-45,20,30],"eulerd","ZYZ","frame");

T = 0.5;

b = slerp(q1,q2,T);

But MATLAB returns error:

Unrecognized function or variable 'slerp'.

When I look it up, the only posts say quaternion must be loaded, and it is indeed loaded since I can see Quaternion objects for q1 and q2. Then, I also installed navigation toolbox, but the problem remains.

[Steven Lord]

Can you show us what you see when you run all of the following commands? The last three are intended to make sure you're calling the quaternion function you think you are (and not one from a different toolbox) and to check what MATLAB thinks it should be calling when you call slerp.

q1 = quaternion([75,-20,-10],"eulerd","ZYZ","frame")

q1 = quaternion
     0.83058 + 0.11732i - 0.12803j + 0.52914k

q2 = quaternion([-45,20,30],"eulerd","ZYZ","frame")

q2 = quaternion
     0.97638 + 0.10571i + 0.13776j - 0.12854k

T = 0.5;
b = slerp(q1,q2,T);
which -all quaternion

/MATLAB/toolbox/shared/rotations/rotationslib/@quaternion/quaternion.m  % quaternion constructor

whos q1 q2

  Name      Size            Bytes  Class         Attributes

  q1        1x1                32  quaternion              
  q2        1x1                32  quaternion              

which -all slerp(q1,q2,T)

/MATLAB/toolbox/shared/rotations/rotationslib/+matlabshared/+rotations/+internal/@quaternionBase/slerp.m  % quaternion method

[Zhangxi Feng]

q1 = quaternion([75,-20,-10],"eulerd","ZYZ","frame")

q2 = quaternion([-45,20,30],"eulerd","ZYZ","frame")

T = 0.5;

b = slerp(q1,q2,T);

which -all quaternion

whos q1 q2

which -all slerp(q1,q2,T)

q1 = quaternion

size: 1 x 3

Error using horzcat

Dimensions of arrays being concatenated are not consistent.

Error in quaternion/display (line 5)

d = [q.a(:),q.b(:),q.c(:),q.d(:)];

Error in quaternion/display (line 17)

display(q,'onlyShowQuaternions')

I installed another aerospace toolbox since then, and now this is the error, I can't even create the quaternion anymore. But I think you are correct. I have the MTEX library and the quaternion was created from MTEX instead of from the MATLAB toolboxes. Is there a way to specify which toolbox to use, or do I have to disable MTEX when I need to do this?

[Zhangxi Feng]

I disabled MTEX and now it works

Answer 1

[Zhangxi Feng]

Thanks to @Steven Lord, I realized that another externally installed library, MTEX, is causing the issue. I disabled MTEX and now it is solved.