Magnitude

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Magnitude (|), or Absolute Value, is a monadic scalar function which gives the absolute value of a real or complex number. Magnitude shares the glyph <syntaxhighlight lang=apl inline>|</source> with the dyadic arithmetic function Residue.

Examples

<syntaxhighlight lang=apl>

     |0 1 2 ¯1 ¯2

0 1 2 1 2

     |0J2 ¯3J¯4

2 5 </source>

Properties

The magnitude of any number is a non-negative real number.

For real numbers, the magnitude equals the original number times (or divided by, for non-zero numbers) its sign.

<syntaxhighlight lang=apl>

     v←0 1E¯100 20 1E300 ¯1E¯100 ¯20 ¯1E300
     (|v)≡v××v

1

     (|v)=v÷×v

0 1 1 1 1 1 1 </source>

For complex numbers, the magnitude is defined as the Euclidean distance from the number 0 on the complex plane.

<syntaxhighlight lang=apl>

     Dist←{0.5*⍨+.×⍨9 11○⍵} ⍝ Square root of square sum of real and imaginary parts
     Dist¨ 0 1J2 ¯3J4

0 2.236067977 5

     |0 1J2 ¯3J4

0 2.236067977 5

</source>

Works in: Dyalog APL

Any real or complex number is equal to the product of its signum and magnitude.

<syntaxhighlight lang=apl>

     (⊢ ≡ ××|) 0 1 1E¯300 ¯2.5 0J3.5 ¯3J¯4

1

</source>

Works in: Dyalog APL

See also

External links

Documentation

APL built-ins [edit]
Primitives (Timeline) Functions
Scalar
Monadic ConjugateNegateSignumReciprocalMagnitudeExponentialNatural LogarithmFloorCeilingFactorialNotPi TimesRollTypeImaginarySquare RootRound
Dyadic AddSubtractTimesDivideResiduePowerLogarithmMinimumMaximumBinomialComparison functionsBoolean functions (And, Or, Nand, Nor) ∙ GCDLCMCircularComplexRoot
Non-Scalar
Structural ShapeReshapeTallyDepthRavelEnlistTableCatenateReverseRotateTransposeRazeMixSplitEncloseNestCut (K)PairLinkPartitioned EnclosePartition
Selection FirstPickTakeDropUniqueIdentityStopSelectReplicateExpandSet functions (IntersectionUnionWithout) ∙ Bracket indexingIndexCartesian ProductSort
Selector Index generatorGradeIndex OfInterval IndexIndicesDealPrefix and suffix vectors
Computational MatchNot MatchMembershipFindNub SieveEncodeDecodeMatrix InverseMatrix DivideFormatExecuteMaterialiseRange
Operators Monadic EachCommuteConstantReplicateExpandReduceWindowed ReduceScanOuter ProductKeyI-BeamSpawnFunction axisIdentity (Null, Ident)
Dyadic BindCompositions (Compose, Reverse Compose, Beside, Withe, Atop, Over) ∙ Inner ProductDeterminantPowerAtUnderRankDepthVariantStencilCutDirect definition (operator)Identity (Lev, Dex)
Quad names Index originComparison toleranceMigration levelAtomic vector