static IndexMappingProvider createPort(IndexMappingProvider opu, Tensor from, Tensor to) {
if (from.hashCode() != to.hashCode()) return IndexMappingProvider.Util.EMPTY_PROVIDER;
if (from.getClass() != to.getClass()) {
Tensor nonComplex;
// Processing case -2*(1/2)*g_mn -> g_mn
if (from instanceof Product && !(to instanceof Product)) {
if (from.size() != 2) return IndexMappingProvider.Util.EMPTY_PROVIDER;
if ((nonComplex = extractNonComplexFactor(from)) != null)
return new MinusIndexMappingProviderWrapper(createPort(opu, nonComplex, to));
return IndexMappingProvider.Util.EMPTY_PROVIDER;
}
// Processing case g_mn -> -2*(1/2)*g_mn
if (to instanceof Product && !(from instanceof Product)) {
if (to.size() != 2) return IndexMappingProvider.Util.EMPTY_PROVIDER;
if ((nonComplex = extractNonComplexFactor(to)) != null)
return new MinusIndexMappingProviderWrapper(createPort(opu, from, nonComplex));
return IndexMappingProvider.Util.EMPTY_PROVIDER;
}
return IndexMappingProvider.Util.EMPTY_PROVIDER;
}
IndexMappingProviderFactory factory = map.get(from.getClass());
if (factory == null) throw new RuntimeException("Unsupported tensor type: " + from.getClass());
return factory.create(opu, from, to);
}
