Package org.hipparchus.util
Class CombinatoricsUtils.FactorialLog
- java.lang.Object
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- org.hipparchus.util.CombinatoricsUtils.FactorialLog
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- Enclosing class:
- CombinatoricsUtils
public static final class CombinatoricsUtils.FactorialLog extends Object
Class for computing the natural logarithm of the factorial ofn. It allows to allocate a cache of precomputed values. In case of cache miss, computation is preformed by a call toGamma.logGamma(double).
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static CombinatoricsUtils.FactorialLogcreate()Creates an instance with no precomputed values.doublevalue(int n)Computeslog(n!).CombinatoricsUtils.FactorialLogwithCache(int cacheSize)Creates an instance with the specified cache size.
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Method Detail
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create
public static CombinatoricsUtils.FactorialLog create()
Creates an instance with no precomputed values.- Returns:
- instance with no precomputed values
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withCache
public CombinatoricsUtils.FactorialLog withCache(int cacheSize)
Creates an instance with the specified cache size.- Parameters:
cacheSize- Number of precomputed values of the function.- Returns:
- a new instance where
cacheSizevalues have been precomputed. - Throws:
MathIllegalArgumentException- ifn < 0.
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value
public double value(int n)
Computeslog(n!).- Parameters:
n- Argument.- Returns:
log(n!).- Throws:
MathIllegalArgumentException- ifn < 0.
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