/// <inheritdoc/>
/// <exception cref="DimensionMismatchException"> if number of free parameters
/// or orders do not match</exception>
public DerivativeStructure multiply(DerivativeStructure a)
{
compiler.checkCompatibility(a.compiler);
DerivativeStructure result = new DerivativeStructure(compiler);
compiler.multiply(data, 0, a.data, 0, result.data, 0);
return(result);
}