Preheat oven to 450 degrees. Combine the sweet potatoes and pineapple in a medium size bowl and drizzle with oil. Toss gently to coat. Sprinkle with spices and toss again. Spread the pieces across a greased baking sheet or a silpat mat lined baking sheet. Bake until the pieces are tender and starting to brown, approximately 30-35 minutes. Stir every 10-15 minutes. (I'm planning to cook mine a bit longer next time and allow the potatoes to begin to crisp a bit. These were delicious as they were, but I think they will be even better a bit more browned.)