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pl-matrix-input element

A pl-matrix-input element displays an input field that accepts a matrix (i.e., a 2-D array) expressed in a supported programming language format (either MATLAB or Python's numpy).

Sample element

Screenshot of the pl-matrix-input element

question.html
<pl-matrix-input answers-name="matrixB" label="$B=$"></pl-matrix-input>
server.py
import prairielearn as pl
import numpy as np

def generate(data):
    # Randomly generate a 2x2 matrix
    matrixB = np.random.random((2, 2))

    # Answer exported to question.
    data["correct_answers"]["matrixB"] = pl.to_json(matrixB)

Customizations

Attribute Type Default Description
allow-complex boolean false Whether to allow complex numbers as answers.
answers-name string — Variable name to store data in. Note that this attribute has to be unique within a question, i.e., no value for this attribute should be repeated within a question.
aria-label string — An accessible label for the element.
atol number 1e-8 Absolute tolerance for comparison="relabs".
comparison "relabs", "sigfig", or "decdig" "relabs" How to grade. "relabs" uses relative (rtol) and absolute (atol) tolerances. "sigfig" and "decdig" use digits significant or decimal digits.
digits integer 2 number of digits that must be correct for comparison="sigfig" or comparison="decdig".
initial-value string — Initial value to prefill the input box the first time it is rendered.
label string — A prefix to display before the input box (e.g., label="$F =$").
rtol number 1e-2 Relative tolerance for comparison="relabs".
show-help-text boolean true Show the question mark at the end of the input displaying required input parameters.
weight integer 1 Weight to use when computing a weighted average score over elements.

Details

pl-matrix-input parses a matrix entered in MATLAB or Python format. The following are valid input format options:

MATLAB format:

[1.23; 4.56]

Python format:

[[1.23], [4.56]]

Note: A scalar will be accepted either as a matrix of size 1 x 1 (e.g., [1.23] or [[1.23]]) or just as a single number (e.g., 1.23).

In the answer panel, a pl-matrix-input element displays the correct answer, allowing the user to switch between matlab and python format.

In the submission panel, a pl-matrix-input element displays either the submitted answer (in the same format that it was submitted, either MATLAB or Python), or a note that the submitted answer was invalid (with an explanation of why).

Example implementations

See also