fb_vars_matrix()

txt: fb_vars_matrix(S, T, [vars, labels, tol])

• txt feedback text, only for the elements with a message (empty otherwise)
• S student's answer (content of a matrix input)
• T teacher's answer, a matrix of the same size
• vars (optional, default []) as for fb_vars: variables whose terms are checked
• labels (optional) names of the elements in the feedback, as for fb_unit_matrix()
• tol (optional, default 0) as for fb_vars

Source

fb_vars_matrix() checks every element of a matrix (or vector) answer with fb_vars and collects the messages, each element on a line of its own, starting with its label. The texts are bilingual (German and English). The argument positions are those of fb_vars(sans, tans, vars, label, tol), with a list of labels instead of a single label.

Like fb_vars(), it returns text only: no message does not prove that the answer is correct. The PRT therefore tests the whole matrix with AlgEquiv and only shows the text.

Example

Input S_xM1 of type Matrix, model answer xM1: matrix([4*a], [3*a]);

PRT xM1:

Field	Value
Feedback variables	txt: fb_vars_matrix(S_xM1, xM1, []);
Answer test	AlgEquiv
SAns	S_xM1
TAns	xM1
Quiet	Yes
Feedback (true and false)	{@txt@}

Student's answer	feedback
[4*a, 3*a]	(none)
[4*a+b, 3*a]	x-component: Unexpected variable b.
[4*a, 3]	y-component: Missing variable a (a).

The Meclib Workbench creates this input, PRT and table row with its input dialog (type "vector / matrix of expressions").

See also Matrix Feedback.