1package io.protobase.f7.formulas.math;
 2
 3import io.protobase.f7.errors.NumException;
 4import io.protobase.f7.formulas.AbstractFormula;
 5import io.protobase.f7.formulas.FormulaName;
 6import io.protobase.f7.models.GridColumnRowKey;
 7import io.protobase.f7.utils.Converters;
 8
 9import java.util.function.BiFunction;
10import java.util.function.Function;
11
12public class ATANH extends AbstractFormula {
13  public static FormulaName NAME = FormulaName.ATANH;
14  public static ATANH SELF = new ATANH();
15
16  public ATANH() {
17    super();
18  }
19
20  public ATANH(Function<Object, Object> lookup, BiFunction<GridColumnRowKey, Object, Object> collateralLookup) {
21    super(lookup, collateralLookup);
22  }
23
24  @Override
25  public Object internal(GridColumnRowKey origin, Object... values) {
26    checkLength(values.length, 1, NAME);
27    double value = Converters.toDouble(Converters.first(collateralLookup.apply(origin, values[0])));
28    if (value <= -1 || value >= 1) {
29      return new NumException(String.format("ATANH parameter 1 value is %f. Valid values are between -1 and 1 exclusively.", values));
30    }
31    return (Math.log(1 + value) - Math.log(1 - value)) / 2;
32  }
33}