This is machine translation

Translated by Microsoft
Mouseover text to see original. Click the button below to return to the English verison of the page.

Note: This page has been translated by MathWorks. Please click here
To view all translated materals including this page, select Japan from the country navigator on the bottom of this page.


Type and property representing zero

MuPAD® notebooks are not recommended. 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.


testtype(obj, Type::Zero)
assume(x, Type::Zero)
is(ex, Type::Zero)


testtype(obj, Type::Zero ) is equivalent to iszero(obj). Type::Zero is a property, too, which can be used in an assume call.

The call testtype(obj, Type::Zero) is equivalent to iszero(obj), which performs a syntactical test if obj is zero. If it is, the call returns TRUE, otherwise, FALSE is returned.

The call assume(x, Type::Zero) marks the identifier x as zero.

The call is(ex, Type::Zero) derives, whether the expression ex is zero (or this property can be derived).

This type represents a property that can be used in assume and is.

The call assume(x = 0) has the same meaning as assume(x, Type::Zero).


Example 1

testtype determines the syntactical equality to zero:

testtype(0.0, Type::Zero)

testtype(x, Type::Zero)

Example 2

Type::Zero can be used within assume and is:

is(x, Type::Zero)

Assumption that x is zero:

assume(x, Type::Zero):
is(x^2, Type::Zero)

The next example shows the difference between testtype and is:

is(x, Type::Zero), testtype(x, Type::Zero)

Now the property of x is removed:

delete x:
is(x, Type::Zero), testtype(x, Type::Zero)

A positive number cannot be zero:

assume(x > 0):
is(x, Type::Zero), testtype(x, Type::Zero)

But in the next example x could be zero:

assume(x >= 0):
is(x, Type::Zero), testtype(x, Type::Zero)

delete x:



Any MuPAD® object


An identifier or a mathematical expression containing identifiers


An arithmetical expression

Return Values

See testtype, assume and is

See Also

MuPAD Functions

Was this topic helpful?