FAIL

Indicate a failed computation

MuPAD® notebooks will be removed in a future release. Use MATLAB® live scripts instead.

MATLAB live scripts support most MuPAD functionality, though there are some differences. For more information, see Convert MuPAD Notebooks to MATLAB Live Scripts.

Syntax

FAIL

Description

FAIL is a keyword of the MuPAD® language. Many functions of the library use the return value FAIL to indicate failed computations or non-existing elements.

FAIL is the only element of the domain DOM_FAIL.

FAIL is used as the return value for computations that failed. Also, requesting non-existing slots of domains or function environments yields FAIL. Due to this behavior, library functions can try computations without provoking errors.

A function should return FAIL or an error if at least one of its inputs is FAIL.

Examples

Example 1

The following attempt to convert sqrt(3) to an integer of a residue class ring must fail:

poly(sqrt(3)*x, [x], Dom::IntegerMod(3))

The following matrix is not invertible. You can try to invert it without producing an error:

A := matrix([[1, 1], [1, 1]]): 1/A

The "inverse" slot of a function environment yields the inverse of the function. The inverse of the sine function is implemented, but MuPAD does not know the inverse of the dilogarithm function:

sin::inverse, dilog::inverse

delete A:

Example 2

Most functions return FAIL or an error on input of FAIL:

poly(FAIL)

sin(FAIL)
Error: Arithmetical expression expected. [sin]

Example 3

FAIL evaluates to itself:

FAIL, eval(FAIL), level(FAIL, 5)

See Also

MuPAD Functions