1+ import { agm } from '../ArithmeticGeometricMean.js'
2+ 3+ describe ( 'Tests for AGM' , ( ) => {
4+ it ( 'should be a function' , ( ) => {
5+ expect ( typeof agm ) . toEqual ( 'function' )
6+ } )
7+ 8+ it ( 'number of parameters should be 2' , ( ) => {
9+ expect ( agm . length ) . toEqual ( 2 )
10+ } )
11+ 12+ const m = 0x100 ; //scale for rand
13+ 14+ it ( 'should return NaN if any or all params has a negative argument' , ( ) => {
15+ //I multiplied by minus one, because the sign inversion is more clearly visible
16+ expect ( agm ( - 1 * Math . random ( ) * m , Math . random ( ) * m ) ) . toBe ( NaN )
17+ expect ( agm ( Math . random ( ) * m , - 1 * Math . random ( ) * m ) ) . toBe ( NaN )
18+ expect ( agm ( - 1 * Math . random ( ) * m , - 1 * Math . random ( ) * m ) ) . toBe ( NaN )
19+ } )
20+ 21+ it ( 'should return Infinity if any arg is Infinity and the other is not 0' , ( ) => {
22+ expect ( agm ( Math . random ( ) * m + 1 , Infinity ) ) . toEqual ( Infinity )
23+ expect ( agm ( Infinity , Math . random ( ) * m + 1 ) ) . toEqual ( Infinity )
24+ expect ( agm ( Infinity , Infinity ) . toEqual ( Infinity ) )
25+ } )
26+ 27+ it ( 'should return NaN if some arg is Infinity and the other is 0' , ( ) => {
28+ expect ( agm ( 0 , Infinity ) . toBe ( NaN ) )
29+ expect ( agm ( Infinity , 0 ) . toBe ( NaN ) )
30+ } )
31+ 32+ it ( 'should return +0 if any or all args are +0 or -0, and return -0 if all are -0' , ( ) => {
33+ expect ( agm ( Math . random ( ) * m , - 0 ) ) . toBe ( 0 )
34+ expect ( agm ( 0 , Math . random ( ) * m ) ) . toBe ( 0 )
35+ expect ( agm ( 0 , - 0 ) . toBe ( 0 ) )
36+ expect ( agm ( - 0 , 0 ) . toBe ( 0 ) )
37+ expect ( agm ( - 0 , - 0 ) . toBe ( - 0 ) )
38+ } )
39+ 40+ it ( 'should return NaN if any or all args are NaN' , ( ) => {
41+ expect ( agm ( Math . random ( ) * m , NaN ) ) . toBe ( NaN )
42+ expect ( agm ( NaN , Math . random ( ) * m ) ) . toBe ( NaN )
43+ expect ( agm ( NaN , NaN ) . toBe ( NaN ) )
44+ } )
45+ 46+ it ( 'should return an accurate approximation of the AGM between 2 valid input args' , ( ) => {
47+ //all the constants are provided by WolframAlpha
48+ expect ( agm ( 1 , 2 ) ) . toBeCloseTo ( 1.4567910310469068691864323832650819749738639432213055907941723832 )
49+ expect ( agm ( 2 , 256 ) ) . toBeCloseTo ( 64.4594071943866695986665434983250898480227029006463800294306182 )
50+ expect ( agm ( 55555 , 34 ) ) . toBeCloseTo ( 9933.40472395519953051873484897963370925448369441581220656590 )
51+ //test "unsafe" numbers
52+ expect ( agm ( 2 ** 48 , 3 ** 27 ) . toBeCloseTo ( 88506556379265.712723873253375677194780 ) )
53+ } )
54+ } )
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