A method executed by a computer includes: obtaining first input information specifying predetermined domain characteristics; obtaining a validity index that quantitatively indicates difficulty in generating output data of the multi-tasking model according to the first input information; generating first guide information specifying the domain characteristics for reducing the generation difficulty based on the obtained validity index; and providing the first guide information. The method further include: obtaining input information specifying predetermined domain characteristics; converting the input information into low-dimensional latent variables represented in a low-dimensional Gaussian space; obtaining sampled latent variables obtained by sampling the converted low-dimensional latent variables; obtaining optimized latent variables obtained by optimizing the obtained sampled latent variables through a genetic algorithm; restoring the optimized latent variables into high-dimensional latent variables represented in a high-dimensional space; and providing the restored high-dimensional latent variables to the multi-tasking model.