hasimag¶
Purpose¶
Tests whether the imaginary part of a complex matrix is negligible.
Format¶

y =
hasimag
(x)¶ Parameters: x (NxK matrix) – data Returns: y (scalar) – 1 if the imaginary part of x has any nonzero elements, 0 if it consists entirely of 0’s.
Examples¶
x = { 1 2 3i,
4i 5 6i,
7 8i 9 };
if hasimag(x);
// code path for complex case
print "X has nonzero imaginary parts"
else;
// code path for real case
print "X does not have nonzero imaginary parts"
endif;
Remarks¶
The function iscplx()
tests whether x is a complex matrix or not, but it
does not test the contents of the imaginary part of x. hasimag()
tests the
contents of the imaginary part of x to see if it is zero.
hasimag()
actually tests the imaginary part of x against a tolerance to
determine if it is negligible. The tolerance used is the imaginary
tolerance set with the sysstate()
command, case 21.
Some functions are not defined for complex matrices. iscplx()
can be used
to determine whether a matrix has no imaginary part and so can pass
through those functions. hasimag()
can be used to determine whether a
complex matrix has a negligible imaginary part and could thus be
converted to a real matrix to pass through those functions.
iscplx()
is useful as a preliminary check because for large matrices it is
much faster than hasimag()
.
See also
Functions iscplx()