DanilaFe/Abacus
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Code Issues Releases Wiki Activity

Rewrite exp. (Now works faster.) Add private factorial function to StandardPlugin as well.

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This commit is contained in:
Arthur Drobot 2017-07-31 14:49:25 -07:00
parent afb57cf69b
commit 68155446b6
1 changed files with 51 additions and 4 deletions
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55
src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
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@ -8,6 +8,8 @@ import org.nwapw.abacus.number.NaiveNumber;
import org.nwapw.abacus.number.NumberInterface; import org.nwapw.abacus.number.NumberInterface;
import org.nwapw.abacus.number.PreciseNumber; import org.nwapw.abacus.number.PreciseNumber;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.function.BiFunction; import java.util.function.BiFunction;
/** /**
@ -16,6 +18,8 @@ import java.util.function.BiFunction;
*/ */
public class StandardPlugin extends Plugin { public class StandardPlugin extends Plugin {
private static HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>> factorialLists = new HashMap<Class<? extends NumberInterface>, ArrayList<NumberInterface>>();
/** /**
* The addition operator, + * The addition operator, +
*/ */
@ -152,17 +156,45 @@ public class StandardPlugin extends Plugin {
@Override @Override
protected NumberInterface applyInternal(NumberInterface[] params) { protected NumberInterface applyInternal(NumberInterface[] params) {
boolean takeReciprocal = params[0].signum() == -1; NumberInterface maxError = getMaxError(params[0]);
params[0] = FUNCTION_ABS.apply(params[0]); int n = 0;
if(params[0].signum() <= 0){
NumberInterface currentTerm = NaiveNumber.ONE.promoteTo(params[0].getClass()), sum = currentTerm;
while(FUNCTION_ABS.apply(currentTerm).compareTo(maxError) > 0){
n++;
currentTerm = currentTerm.multiply(params[0]).divide((new NaiveNumber(n)).promoteTo(params[0].getClass()));
sum = sum.add(currentTerm);
}
return sum;
}
else{
//We need n such that x^(n+1) * 3^ceil(x) <= maxError * (n+1)!.
//right and left refer to lhs and rhs in the above inequality.
NumberInterface sum = NaiveNumber.ONE.promoteTo(params[0].getClass());
NumberInterface nextTerm = params[0];
NumberInterface left = params[0].multiply(new NaiveNumber(3).promoteTo(params[0].getClass()).intPow(params[0].ceiling())), right = maxError;
do{
sum = sum.add(nextTerm);
n++;
NumberInterface nextN = new NaiveNumber(n+1).promoteTo(params[0].getClass());
nextTerm = nextTerm.multiply(params[0]).divide(nextN);
left = left.multiply(params[0]);
right = right.multiply(nextN);
}
while(left.compareTo(right) > 0);
return sum;
}
/*boolean takeReciprocal = params[0].signum() == 1;
params[0] = FUNCTION_ABS.apply(params[0]).negate();
NumberInterface sum = sumSeries(params[0], StandardPlugin::getExpSeriesTerm, getNTermsExp(getMaxError(params[0]), params[0])); NumberInterface sum = sumSeries(params[0], StandardPlugin::getExpSeriesTerm, getNTermsExp(getMaxError(params[0]), params[0]));
if (takeReciprocal) { if (takeReciprocal) {
sum = NaiveNumber.ONE.promoteTo(sum.getClass()).divide(sum); sum = NaiveNumber.ONE.promoteTo(sum.getClass()).divide(sum);
} }
return sum; return sum;*/
} }
}; };
/** /**
* The natural log function, ln(exp(1)) = 1 * The natural log function.
*/ */
public static final Function FUNCTION_LN = new Function() { public static final Function FUNCTION_LN = new Function() {
@Override @Override
@ -339,4 +371,19 @@ public class StandardPlugin extends Plugin {
} }
public static NumberInterface factorial(Class<? extends NumberInterface> numberClass, int n){
if(!factorialLists.containsKey(numberClass)){
factorialLists.put(numberClass, new ArrayList<NumberInterface>());
factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
factorialLists.get(numberClass).add(NaiveNumber.ONE.promoteTo(numberClass));
}
ArrayList<NumberInterface> list = factorialLists.get(numberClass);
if(n >= list.size()){
while(list.size() < n + 16){
list.add(list.get(list.size()-1).multiply(new NaiveNumber(list.size()).promoteTo(numberClass)));
}
}
return list.get(n);
}
} }