CVS difference for ais/ai-00156.txt

Differences between 1.2 and version 1.3
Log of other versions for file ais/ai-00156.txt

```--- ais/ai-00156.txt	1998/09/30 23:25:17	1.2
+++ ais/ai-00156.txt	1999/07/08 17:25:14	1.3
@@ -1,5 +1,6 @@
-!standard G.1.1    (55)                               98-06-12  AI95-00156/03
+!standard G.1.1    (55)                               99-07-07  AI95-00156/04
!class binding interpretation 96-09-04
+!status Corrigendum 2000 99-05-27
!status WG9 approved 98-06-12
!status ARG Approved (with changes) 12-0-1  97-11-16
!status work item 96-09-08
@@ -8,7 +9,7 @@
!difficulty Medium
!subject Polar implementation of complex exponentiation for negative exponents

-!summary 98-03-27
+!summary

The second sentence of G.1.1(55) should read:

@@ -19,7 +20,7 @@
argument by the given exponent, and reconverting to a cartesian
representation.

-!question 96-09-08
+!question

G.1.1(55) gives the following method for doing complex exponentiation
in polar form in G.1.1(55):
@@ -34,15 +35,15 @@
exponents should be applied for all exponents, including interestingly
enough, zero exponents.

-!recommendation 98-03-27
+!recommendation

(See summary.)

-!wording 98-03-27
+!wording

(See summary.)

-!discussion 96-09-08
+!discussion

Here is a proof by example that the given method is incorrect:

@@ -64,7 +65,42 @@
The only dubious assumption made was that the RM95 method was correct.
So, it must not be.

-!appendix 96-09-04
+!corrigendum G.01.01(55)
+
+@drepl
+Implementations may obtain the result of exponentiation of a complex or
+pure-imaginary operand by repeated complex multiplication, with arbitrary
+association of the factors and with a possible final complex reciprocation
+(when the exponent is negative).  Implementations are also permitted to
+obtain the result of exponentiation of a complex operand, but not of a
+pure-imaginary operand, by converting the left operand to a polar
+representation; exponentiating the modulus by the given exponent; multiplying
+the argument by the given exponent, when the exponent is positive, or
+dividing the argument by the absolute value of the given exponent, when the
+exponent is negative; and reconverting to a cartesian representation.
+Because of this implementation freedom, no accuracy requirement is imposed on
+complex exponentiation (except for the prescribed results given above, which
+apply regardless of the implementation method chosen).
+@dby
+Implementations may obtain the result of exponentiation of a complex or
+pure-imaginary operand by repeated complex multiplication, with arbitrary
+association of the factors and with a possible final complex reciprocation
+(when the exponent is negative). Implementations are also permitted to
+obtain the result of exponentiation of a complex operand, but not of a
+pure-imaginary operand, by converting the left operand to a polar
+representation, exponentiating the modulus by the given exponent,
+multiplying the argument by the given exponent, and reconverting to a
+cartesian representation. Because of this implementation freedom, no
+accuracy requirement is imposed on complex exponentiation (except for the
+prescribed results given above, which apply regardless of the
+implementation method chosen).
+
+!ACATS test
+
+This is a correction of a permission for an implementation to use a
+non-canonical algorithm. This is not testable.
+
+!appendix

!section G.1.1(55)
!subject Polar implementation of complex exponentiation for negative exponents incorrect.
```

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