Round decimals in Java

Question

Im trying to round some double decimals, because I am getting only 0.0 as result of division. I tried using the BigDecimal way and the String.format(), however I still get O.00 at: Relation Aromatics/Aliphatics: 0,00 Relation Heterocyclics/Aliphatics: 0,00 Relation Heterocyclics/Aromatic: 0,00

How could I fix that?? the values should be: Relation Aromatics/Aliphatics: 0,14 Relation Heterocyclics/Aliphatics: 0,12 Relation Heterocyclics/Aromatic: 0,875

This is the code:

import java.io.InputStream; import java.net.URL; import java.util.Set;

import org.biojava.nbio.core.sequence.ProteinSequence; import org.biojava.nbio.core.sequence.compound.AminoAcidCompound; import org.biojava.nbio.core.sequence.io.FastaReaderHelper;

public class BioSeq { ProteinSequence seq = getSequenceForId ("P31574");

    int polarCount = numberOfOccurrences(seq, new HashSet<>(Arrays.asList("Y", "S", "T", "N", "Q", "C","H","R","D","E","K")));
    double polar = ((double)(polarCount));
    
    int NonPolarCount = numberOfOccurrences(seq, new HashSet<>(Arrays.asList("A","V","L","G","I","M","W","P","F")));
    double NonPolar = ((double)(NonPolarCount));
    
    int Aromatic = numberOfOccurrences(seq, new HashSet<>(Arrays.asList("W","Y","F","H")));
    double AromaticCount = ((double)(Aromatic));
    
    int Aliphatic = numberOfOccurrences(seq, new HashSet<>(Arrays.asList("A","V","L","I","P","G","R")));
    double AliphaticCount = ((double)(Aliphatic));
    
    int Heterocyclics = numberOfOccurrences(seq, new HashSet<>(Arrays.asList("W","H","P")));
    double HeteroCount = ((double)(Heterocyclics));
    
    double rel_polarity = (polar/NonPolar); 
    double rel_arom = (Aromatic/Aliphatic);         
    double rel_alip = (Heterocyclics/Aliphatic);    
    double rel_hetero = (Heterocyclics/Aromatic);   
            
    
    System.out.println("Полярные АМК: " + polar);
    System.out.println("Неполярные АМК: " + NonPolar);
    System.out.println("Ароматичесие АМК: " + AromaticCount);
    System.out.println("Алифатические АМК: " + AliphaticCount);
    System.out.println("Гетероциклические АМК: " + HeteroCount);
    System.out.println("_______________________");
    System.out.println("Relations and Percentages: ");
        
    System.out.println("Relation Polar/No polars: " + String.format("%.2f",rel_polarity));
    System.out.println("Relation Aromatics/Aliphatics: " + String.format("%.2f",rel_arom));
    System.out.println("Relation Heterocyclics/Aliphatics: " + String.format("%.2f",rel_alip));
    System.out.println("Relation Heterocyclics/Aromatic: " + String.format("%.2f",rel_hetero));

try {
        System.out.println(getSequenceForId("P31574"));
    } catch (Exception e) {
        e.printStackTrace();
    }
}
private static int numberOfOccurrences(ProteinSequence seq, Set<String> bases) {
    int count = 0;
    for (AminoAcidCompound aminoAcid : seq)
        if(bases.contains(aminoAcid.getBase()))
            count++;
    return count;
}}

Answer 1

double rel_polarity = ((double)polar/(double)NonPolar)*100;

double rel_arom = ((double)Aromatic/(double)Aliphatic)*100;

double rel_alip = ((double)Heterocyclics/(double)Aliphatic)*100;

double rel_hetero = ((double)Heterocyclics/(double)Aromatic)*100;