PrimeFactors (BandM metatools API doc)

java.lang.Object
- eu.bandm.tools.util2.PrimeFactors

```
public class PrimeFactors
extends Object
```
Calculates prime factor combinations for Rationals, i.e. positive or negative exponents. Objects exist in two flavours:
Modifiable for setting and clearing exponents.
Unmodifiable for being cached and cheaply retrieved.
Between these flavours there are conversion functions, making new copies.
Internally they maintain a Map from bases to exponents. Bases with exponent==0 are removed from the maps.

Field Summary

Fields
Modifier and Type	Field and Description
`static Comparator<PrimeFactors>`	`byIntValue`
`static Comparator<PrimeFactors>`	`byRatValue`
`protected static Map<Integer,PrimeFactors>`	`cache_int`
`protected static Map<Rational,PrimeFactors>`	`cache_rat`
`static PrimeFactors`	`ONE`
`static PrimeFactors`	`TWO`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`add(int p)` Add 1(one) to the currently present exponent (maybe ==0) of p.
`void`	`add(int p, int v)` Add exponent v to the currently present exponent (maybe ==0) of p.
`void`	`clear()` Clear all exponents to zero(0).
`int`	`cmp(PrimeFactors other)` Returns -1/0/+1 for inclusion or equality, negative exponents are smaller than positives, and returns a different int (here: -100) iff not comparable.
`boolean`	`containsAsFactor(PrimeFactors b)` Returns whether arg is a factor of this
`int`	`count(int p)`
`int`	`countBases()`
`int`	`countFactors()`
`PrimeFactors`	`denominator()`
`SortedSet<Integer>`	`domain()` Only those bases with exp!=0
`PrimeFactors`	`enumerator()`
`boolean`	`equals(Object b)`
`boolean`	`equals(PrimeFactors b)`
`static PrimeFactors`	`get(BigInteger bi)`
`static PrimeFactors`	`get(int value)`
`static PrimeFactors`	`get(Rational rat)`
`int`	`hashCode()`
`int`	`intValue()` Return the integer value.
`boolean`	`isInteger()`
`boolean`	`isOne()`
`boolean`	`isPowerOf(int b)` Whether this is a power (with an exponent !=0) of the one single basis.
`static boolean`	`isPrime(int i)` Whether the argument is a prim number >=1.
`static boolean`	`isSingleBased(int i)` Whether the argument is a power of only one single basis.
`PrimeFactors`	`max(PrimeFactors b)` Return an instance with the more positive exponents of both arguments.
`PrimeFactors`	`min(PrimeFactors b)` Return an instance with the more negative exponents of both arguments.
`PrimeFactors`	`minus(PrimeFactors b)` Subtract exponents, ie.
`PrimeFactors`	`modifiable()` Always makes a new copy, which is modifiable.
`PrimeFactors`	`plus(PrimeFactors b)` Add exponents, ie.
`Rational`	`ratValue()` Return the rational value.
`void`	`removeDomain(int p)` Remove basis from domain.
`List<Integer>`	`simpleFactors(boolean reverse)` Iterate over identic factors seperated, like "2, 2, 3, 5, 5", not "4,3,25".
`String`	`toString()`
`PrimeFactors`	`unmodifiable()` Make a new unmodifiable version, iff not already unmodifiable.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - cache_int
```
protected static Map<Integer,PrimeFactors> cache_int
```
  - cache_rat
```
protected static Map<Rational,PrimeFactors> cache_rat
```
  - ONE
```
public static final PrimeFactors ONE
```
  - TWO
```
public static final PrimeFactors TWO
```
  - byRatValue
```
public static Comparator<PrimeFactors> byRatValue
```
  - byIntValue
```
public static Comparator<PrimeFactors> byIntValue
```
- Method Detail
  - modifiable
```
public PrimeFactors modifiable()
```
    Always makes a new copy, which is modifiable.
  - unmodifiable
```
public PrimeFactors unmodifiable()
```
    Make a new unmodifiable version, iff not already unmodifiable.
  - get
```
public static PrimeFactors get(BigInteger bi)
```
    Returns:
    
    an unmodifiable prime factor map for the given value.
  - get
```
public static PrimeFactors get(int value)
```
    Returns:
    
    an unmodifiable prime factor map for the given value.
  - get
```
public static PrimeFactors get(Rational rat)
```
    Returns:
    
    the prime factor map for the given value.
  - isPrime
```
public static boolean isPrime(int i)
```
    Whether the argument is a prim number >=1. 1 and 2 count as prime.
  - isSingleBased
```
public static boolean isSingleBased(int i)
```
    Whether the argument is a power of only one single basis.
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - isOne
```
public boolean isOne()
```
  - isInteger
```
public boolean isInteger()
```
  - count
```
public int count(int p)
```
    Returns:
    
    the exponent for the given base.
  - countBases
```
public int countBases()
```
    Returns:
    
    the number of different bases.
  - countFactors
```
public int countFactors()
```
    Returns:
    
    the number of different factors, which is the sum of the absolute values of all exponents.
  - intValue
```
public int intValue()
```
    Return the integer value. If there is no such, ie. some exponent is negative, an IllegalArgumentException is thrown. If "this" was created with an exponent map, this value must be calculated and is stored locally iff this is not modifiable.
  - ratValue
```
public Rational ratValue()
```
    Return the rational value. If "this" was created with an exponent map, this value must be calculated and is stored locally iff this is not modifiable.
  - domain
```
public SortedSet<Integer> domain()
```
    Only those bases with exp!=0
  - isPowerOf
```
public boolean isPowerOf(int b)
```
    Whether this is a power (with an exponent !=0) of the one single basis.
  - simpleFactors
```
public List<Integer> simpleFactors(boolean reverse)
```
    Iterate over identic factors seperated, like "2, 2, 3, 5, 5", not "4,3,25".
  - add
```
public void add(int p)
```
    Add 1(one) to the currently present exponent (maybe ==0) of p. Only supported if modifiable==true.
  - add
```
public void add(int p,
                int v)
```
    Add exponent v to the currently present exponent (maybe ==0) of p. Only supported if modifiable==true.
  - removeDomain
```
public void removeDomain(int p)
```
    Remove basis from domain. Only supported if modifiable==true.
  - clear
```
public void clear()
```
    Clear all exponents to zero(0). Only supported if modifiable==true.
  - cmp
```
public int cmp(PrimeFactors other)
```
    Returns -1/0/+1 for inclusion or equality, negative exponents are smaller than positives, and returns a different int (here: -100) iff not comparable.
  - containsAsFactor
```
public boolean containsAsFactor(PrimeFactors b)
```
    Returns whether arg is a factor of this
  - max
```
public PrimeFactors max(PrimeFactors b)
```
    Return an instance with the more positive exponents of both arguments.
  - min
```
public PrimeFactors min(PrimeFactors b)
```
    Return an instance with the more negative exponents of both arguments.
  - minus
```
public PrimeFactors minus(PrimeFactors b)
```
    Subtract exponents, ie. divide values.
  - plus
```
public PrimeFactors plus(PrimeFactors b)
```
    Add exponents, ie. multiply values.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object b)
```
    Overrides:
    
    equals in class Object
  - equals
```
public boolean equals(PrimeFactors b)
```
  - denominator
```
public PrimeFactors denominator()
```
    Returns:
    
    prime factors in denominator, as positive exponents of the original negatives.
  - enumerator
```
public PrimeFactors enumerator()
```
    Returns:
    
    prime factors in enumerators, i.e. all which are originally positive.

Class PrimeFactors

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

cache_int

cache_rat

ONE

TWO

byRatValue

byIntValue

Method Detail

modifiable

unmodifiable

get

get

get

isPrime

isSingleBased

toString

isOne

isInteger

count

countBases

countFactors

intValue

ratValue

domain

isPowerOf

simpleFactors

add

add

removeDomain

clear

cmp

containsAsFactor

max

min

minus

plus

hashCode

equals

equals

denominator

enumerator