包括随机梯度算法，相对梯度算法，二维声子晶体FDTD方法计算禁带宽度的例子,包含特征值与特征向量的提取、训练样本以及最后的识别。- Including stochastic gradient algorithm, the relative gradient algorithm, Dimensional phononic crystals FDTD method calculation examples band gap, Contains the eigenvalue and eigenvector extraction, the training sample, and the final recognition.