org.github.evenjn.numeric.NumericUtils Maven / Gradle / Ivy
/**
*
* Copyright 2016 Marco Trevisan
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.github.evenjn.numeric;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Vector;
import java.util.function.Function;
import org.github.evenjn.knit.Bik;
import org.github.evenjn.knit.KnittingCursor;
import org.github.evenjn.yarn.Bi;
import org.github.evenjn.yarn.Cursor;
import org.github.evenjn.yarn.EndOfCursorException;
public class NumericUtils {
public static double sumDoubles(Iterable numbers) {
double r = 0;
for (Double d: numbers) {
r = r + d;
}
return r;
}
public static Summation summation(int buffer_size, Function, Double> sum) {
return new Summation( buffer_size, sum);
}
public static class Summation {
private final int buffer_size;
private Function, Double> sum;
public Summation(int buffer_size, Function, Double> sum) {
this.sum = sum;
layers.add( new LinkedList<>( ) );
this.buffer_size = buffer_size;
}
private Vector> layers = new Vector<>( );
public void add(double value) {
makeSureThereIsFreeSpace( 0 );
layers.get( 0 ).add( value );
}
public double getSum() {
LinkedList values = new LinkedList<>( );
for (LinkedList list : layers) {
for (Double d : list) {
values.add( d );
}
}
return this.sum.apply( values );
}
private void makeSureThereIsFreeSpace( int level ) {
if (level + 1 > layers.size( )) {
layers.add( new LinkedList<>( ));
return;
}
LinkedList list = layers.get( level );
if (list.size( ) < buffer_size) {
return;
}
makeSureThereIsFreeSpace( level + 1 );
double sum = this.sum.apply( list );
layers.get( level + 1 ).add( sum );
list.clear( );
}
}
public static int raiseInt( int base, int exponent ) {
int result = 1;
for ( int i = 0; i < exponent; i++ ) {
result = result * base;
}
return result;
}
public static Bi argmax( Function function, Cursor set ) {
double max = 0d;
I result = null;
for ( I input : KnittingCursor.wrap( set ).once( ) ) {
if ( result == null ) {
result = input;
max = function.apply( input );
continue;
}
double tmp = function.apply( input );
if ( tmp > max ) {
max = tmp;
result = input;
}
}
return Bik.nu( result, max );
}
public static I argmax( Iterable set, Function function ) {
boolean found = false;
double max = 0d;
I result = null;
for ( I input : set ) {
double tmp = function.apply( input );
if ( !found || tmp > max ) {
found = true;
result = input;
max = tmp;
}
}
return result;
}
public static I argmax( Cursor set, Function function ) {
boolean found = false;
double max = 0d;
I result = null;
for ( I input : KnittingCursor.wrap( set ).once( ) ) {
double tmp = function.apply( input );
if ( !found || tmp > max ) {
found = true;
result = input;
max = tmp;
}
}
return result;
}
public static Double sum( Function function, Cursor set ) {
double result = 0d;
for ( I input : KnittingCursor.wrap( set ).once( ) ) {
result += function.apply( input );
}
return result;
}
public static Double sum( Cursor set, Function function ) {
double result = 0d;
for ( I input : KnittingCursor.wrap( set ).once( ) ) {
result += function.apply( input );
}
return result;
}
public static > I max( Cursor set ) {
I result = null;
for ( I input : KnittingCursor.wrap( set ).once( ) ) {
if ( result == null || result.compareTo( input ) < 0 ) {
result = input;
}
}
return result;
}
public static > I min( Cursor set ) {
I result = null;
for ( I input : KnittingCursor.wrap( set ).once( ) ) {
if ( result == null || result.compareTo( input ) > 0 ) {
result = input;
}
}
return result;
}
public static Double sum( Iterable set, Function function ) {
double result = 0d;
for ( I input : set ) {
result += function.apply( input );
}
return result;
}
public static Double product( Iterable set,
Function function ) {
double result = 1d;
for ( I input : set ) {
result *= function.apply( input );
}
return result;
}
private static Iterator asIterator(Cursor cursor) {
return KnittingCursor.wrap(cursor).once().iterator();
}
/**
* Returns all pairs [ 0 0 ] [ 0 1 ] [ 0 2 ] .. [ 0 ( max - 1 ) ] [ 1 0 ] [ 1
* 1 ] [ 1 2 ] .. [ 1 ( max - 1 ) ] [ ( max - 1 ) 0 ] [ ( max - 1 ) 1 ] [ (
* max - 1 ) 2 ] .. [ ( max - 1 ) ( max - 1 ) ]
*
*
*/
public static Iterable> birange( final int max ) {
return new Iterable>( ) {
@Override
public Iterator> iterator( ) {
final Bik bi = Bik.nu( 0, -1 );
return asIterator( new Cursor>( ) {
@Override
public Bi next( )
throws EndOfCursorException {
int first = bi.front( );
int second = bi.back( );
if ( second + 1 == max ) {
if ( first + 1 == max )
throw EndOfCursorException.neo();
first = first + 1;
second = 0;
}
else {
second = second + 1;
}
bi.set( first, second );
return bi;
}
} );
}
};
}
/*
* Range generators
*/
public static Iterable range( final int to ) {
return range( 0, to );
}
public static Iterable range( final int from, final int to ) {
return new Iterable( ) {
@Override
public Iterator iterator( ) {
return asIterator(new Cursor( ) {
private int current = from;
@Override
public Integer next( )
throws EndOfCursorException {
if ( current >= to )
throw EndOfCursorException.neo();
return current++;
}
} );
}
};
}
public static Iterable range( final long to ) {
return range( 0, to );
}
public static Iterable range( final long from, final long to ) {
return new Iterable( ) {
@Override
public Iterator iterator( ) {
return asIterator( new Cursor( ) {
private long current = from;
@Override
public Long next( )
throws EndOfCursorException {
if ( current >= to )
throw EndOfCursorException.neo();
return current++;
}
} );
}
};
}
}
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