phase
phase Function
Syntax:
phase number → phase
Arguments and Values:
number—a number .
phase—a number .
Description:
phase returns the phase of number (the angle part of its polar representation) in radians, in the range −π (exclusive) if minus zero is not supported, or −π (inclusive) if minus zero is supported, to π (inclusive). The phase of a positive real number is zero; that of a negative real number is π. The phase of zero is defined to be zero.
If number is a complex float, the result is a float of the same type as the components of number. If number is a float, the result is a float of the same type. If number is a rational or a complex rational, the result is a single float.
The branch cut for phase lies along the negative real axis, continuous with quadrant II. The range consists of that portion of the real axis between −π (exclusive) and π (inclusive).
The mathematical definition of phase is as follows:
(phase x) = (atan (imagpart x) (realpart x))
Examples:
(phase 1) → 0.0s0
(phase 0) → 0.0s0
(phase (cis 30)) → -1.4159266
(phase #c(0 1)) → 1.5707964
Exceptional Situations:
Should signal type-error if its argument is not a number . Might signal arithmetic-error.
See Also:
Section 12.1.3.3 (Rule of Float Substitutability)
Expanded Reference: phase
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(phase )