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Function PHASE

Syntax

  • phase numberphase

Arguments and Values

Description

phase returns the phase of number (the angle part of its polar representation) in radians, in the range (exclusive) if minus zero is not supported, or (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 (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

Side Effects

None.

Affected By

None.

Exceptional Situations

Should signal type-error if its argument is not a number. Might signal arithmetic-error.

See Also

  • {\secref\FloatSubstitutability}

Notes

None.

\issue{IEEE-ATAN-BRANCH-CUT:SPLIT} \issue{REAL-NUMBER-TYPE:X3J13-MAR-89} \issue{REAL-NUMBER-TYPE:X3J13-MAR-89} \issue{IEEE-ATAN-BRANCH-CUT:SPLIT}