Examples of NameDescriptor

cc.redberry.core.context.NameDescriptor

This class reflects a unique mathematical nature of simple tensors and tensor fields. It holds the information about string name of simple tensor, structure of its indices and arguments (in case of tensor field). Two simple tensors are considered to have different mathematical nature if and only if their name descriptors are not equal. Each simple tensor with unique mathematical nature have its own unique integer identifier, which is hold in the name descriptor. For example, tensors A_mn and A_ij have same mathematical origin and thus have similar integer identifiers and both have unique same name descriptor (same reference). In contrast, for example, tensors A_mn and A_i have different mathematical origin and different integer identifiers.

This class have no public constructor, since Redberry should be confident, that tensors with same mathematical origin have same descriptors, and the work with descriptors should be carried out through {@link NameManager}. The only way to receive name descriptor from raw information about tensor is via {@link NameManager#mapNameDescriptor(String,cc.redberry.core.indices.StructureOfIndices)}. In order to receive the descriptor from unique simple tensor identifier, one should use {@link NameManager#getNameDescriptor(int)}

@author Dmitry Bolotin @author Stanislav Poslavsky @since 1.0

            throw new IllegalArgumentException("Illegal derivative indices.");


        int[] orders = new int[parent.size()];
        orders[argPosition] = order;
        NameDescriptorForTensorField fieldDescriptor = parent.getNameDescriptor();
        NameDescriptor derivativeDescriptor = fieldDescriptor.getDerivative(orders);


        SimpleIndices totalIndices;


        if (!fieldDescriptor.isDerivative() || derivativeIndices.size() == 0 || parent.indices.size() == 0) {
            totalIndices = new SimpleIndicesBuilder().append(parent.getIndices()).append(derivativeIndices).getIndices();
        } else {
            orders = fieldDescriptor.getDerivativeOrders();


            SimpleIndicesBuilder ib = new SimpleIndicesBuilder();
            StructureOfIndices[] structures = fieldDescriptor.getStructuresOfIndices();
            int i, from;
            SimpleIndices singleType;
            IndexType eType;
            for (byte type = IndexType.TYPES_COUNT - 1; type >= 0; --type) {
                eType = IndexType.values()[type];
                singleType = parent.getIndices().getOfType(eType);
                from = fieldDescriptor.getParent().getStructureOfIndices().getTypeData(type).length;
                for (i = 0; i <= argPosition; ++i)
                    from += structures[i + 1].getTypeData(type).length * orders[i];
                for (i = 0; i < from; ++i)
                    ib.append(singleType.get(i));
                ib.append(derivativeIndices.getOfType(eType));
                for (; i < singleType.size(); ++i)
                    ib.append(singleType.get(i));
            }
            totalIndices = ib.getIndices();
        }


        return new TensorField(derivativeDescriptor.getId(),
                UnsafeIndicesFactory.createOfTensor(derivativeDescriptor.getSymmetries(), totalIndices),
                parent.args, parent.argIndices);
    }

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Examples of NameDescriptor

Examples of cc.redberry.core.context.NameDescriptor