ref()
Catalog >
ref(
Matrix1
[
,
Tol
]
)
⇒
matrix
Returns the row echelon form of
Matrix1
.
Optionally, any matrix element is treated as
zero if its absolute value is less than
Tol
.
This tolerance is used only if the matrix has
floating-point entries and does not contain
any symbolic variables that have not been
assigned a value. Otherwise,
Tol
is ignored.
•
If you use
/·
or set the
Auto or
Approximate
mode to Approximate,
computations are done using floating-
point arithmetic.
•
If
Tol
is omitted or not used, the default
tolerance is calculated as:
5E
−
14
•
max(dim(
Matrix1
))
•
rowNorm
(
Matrix1
)
Avoid undefined elements in
Matrix1
. They
can lead to unexpected results.
For example, if
a
is undefined in the
following expression, a warning message
appears and the result is shown as:
The warning appears because the
generalized element 1/
a
would not be valid
for
a
=0.
You can avoid this by storing a value to
a
beforehand or by using the constraint (“|”)
operator to substitute a value, as shown in
the following example.
Note:
See also
rref()
, page 153.
Alphabetical Listing
145
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