Same values's aswer in MATLAB Grader but identified as a mistake.

The references solution for 'f' is:

a = 4 
m = 3 
b = -3 
l = 6 
C1 = -0.42 
C2 = -4.00 
C3 = -2.07 
C4 = 0.30

t = -10:0.1:10;
s = t.*(t>=0 & t<=1);

sa = (t-a).*((t-a)>=0 & (t-a)<=1);

sm = m.*s;

sb = (t/b).*((t/b)>=0 & (t/b)<=1);

sdr = (l-t).*((l-t)>=0 & (l-t)<=1);


f = C1*sa + C2*sm + C3*sb + C4*sdr;

The student's solution is:

f = ((-0.42)*t+1.68).*(t>=4 & t<=5)-12*t.*(t>=0 & t<=1) + (0.69)*t.*(t<=0 & t>=(-3))+(1.8-0.3*t).*(t<=6 & t>=5);

The solutions should be the same. But when them there is a size 1.6653e-16 error, so the student's answer is not accepted.

Answer 1

[Cris LaPierre]

How have you set up your assessment test? Are you using the Variable Equals Reference Solution test or a MATLAB Code test type? If MATLAB Code, have you incorporated tolerances into your equality check?

When I test the code you have shared in Grader, the learner solution's value of f is marked correct.

I used the drop down test "Variable equals reference solution" and entered f as the "variable name you want to compare". This automatically applies a +/- 0.1% relative or +/- 0.0001 absolute tolerance to the solution. This means a difference of 1.6653e-16 is considered equal.

[Cris LaPierre]

Here is a picture of how I set up the assessment test.