torch.set_printoptions
torch.set_printoptions
设置pytorch打印张量时的选项，比如限制打印的元素数量、设置精度等。在打印大张量或者需要更精确控制输出格式时非常有用。
torch.set_printoptions(precision=None, threshold=None, edgeitems=None, linewidth=None, profile=None, sci_mode=None)
precision– 浮点输出的精度位数（默认值 = 4）。threshold– 输出的数组元素总数（默认值 = 1000）。edgeitems– 每个维度开头和结尾的元素数 （默认值 = 3）。linewidth– 用于插入换行符的每行字符数（默认值 = 80）。profile– 打印选项。可被上述任何选项覆盖。（三个选项：default、short、full）sci_mode– 启用 （True） 或禁用 （False） 科学记数法。
示例 1：设置打印的元素数量
import torch
# 创建一个大张量
big_tensor = torch.randn(1000, 1000)
# 设置打印选项，限制每行打印的元素数量为5
torch.set_printoptions(edgeitems=5)
# 打印大张量
print(big_tensor)
'''output
tensor([[ 7.096e-01, -2.319e-01, -3.508e-01, -1.490e+00, -2.094e+00, ..., 2.418e+00,
2.191e+00, -1.097e+00, -8.462e-03, 1.543e+00],
[-3.659e-01, -2.529e+00, -5.387e-01, -9.730e-01, 1.106e+00, ..., 2.867e-01,
-2.998e-01, 1.395e+00, 1.922e-01, -2.857e+00],
[-1.248e+00, 9.511e-02, 1.104e+00, -2.893e-01, 2.386e-01, ..., -4.030e-01,
-1.431e+00, 1.698e+00, 7.792e-02, 5.647e-01],
[-8.082e-01, -1.269e+00, -9.518e-01, -1.230e+00, 1.623e-01, ..., 6.505e-01,
1.299e-01, -2.172e+00, 9.718e-01, 1.547e-01],
[ 3.541e-01, -1.212e+00, 1.333e+00, -8.269e-01, 3.842e-01, ..., -2.083e-01,
2.715e+00, 1.210e+00, -1.783e+00, -7.736e-01],
...,
[ 3.425e-02, -6.938e-01, 6.390e-02, -1.265e+00, 3.217e-01, ..., 1.713e+00,
5.801e-01, 1.101e+00, -1.443e+00, -2.739e-01],
[ 8.133e-01, -1.418e+00, -6.581e-01, 2.327e+00, 1.146e+00, ..., 6.545e-01,
-7.152e-01, -6.270e-01, -9.436e-01, -1.858e+00],
[ 1.339e+00, 6.877e-02, -1.111e+00, 8.770e-01, 1.358e+00, ..., -2.793e+00,
-1.135e-01, 1.498e+00, 6.292e-01, 1.196e+00],
[-1.095e-01, 6.439e-01, -7.375e-01, 4.185e-01, -1.045e-01, ..., -1.521e+00,
6.631e-01, 2.701e-01, 1.107e-01, -1.860e-01],
[-1.281e+00, 3.997e-01, 1.881e-03, 1.170e+00, 4.183e-01, ..., 3.738e-01,
5.330e-01, -2.445e-01, 7.956e-01, -7.097e-01]], device='cuda:0')
'''
示例 2：设置打印的精度
import torch
# 创建一个包含小数的张量
tensor = torch.tensor([1.123456789, 2.987654321])
# 设置打印选项，限制打印的浮点数精度为3位小数
torch.set_printoptions(precision=3)
# 打印张量
print(tensor)
'''output
tensor([1.123, 2.988], device='cuda:0')
'''
示例 3：设置科学记数法的阈值
import torch
# 创建一个包含大数和小子数的张量
tensor = torch.tensor([1e-5, 1e5])
# 设置打印选项，当绝对值小于1e-3时使用科学记数法
torch.set_printoptions(sci_mode=True, threshold=1e3)
# 打印张量
print(tensor)
'''output
tensor([1.000e-05, 1.000e+05], device='cuda:0')
'''
示例 4：设置张量的边距
import torch
# 创建一个张量
tensor = torch.randn(5, 5)
# 设置打印选项，行字符宽度
torch.set_printoptions(edgeitems=3, linewidth=40)
# 打印张量
print(tensor)
# 设置打印选项，行字符宽度
torch.set_printoptions(edgeitems=3, linewidth=50)
# 打印张量
print(tensor)
'''output
tensor([[-0.787, 0.227, -1.878, 0.286,
-0.899],
[ 0.483, 1.054, 0.770, -0.245,
1.599],
[ 0.165, -0.034, 1.457, -0.944,
0.601],
[-0.150, 0.388, -0.811, -0.741,
1.286],
[-0.657, -0.895, 0.680, 0.946,
-1.832]], device='cuda:0')
tensor([[-0.787, 0.227, -1.878, 0.286, -0.899],
[ 0.483, 1.054, 0.770, -0.245, 1.599],
[ 0.165, -0.034, 1.457, -0.944, 0.601],
[-0.150, 0.388, -0.811, -0.741, 1.286],
[-0.657, -0.895, 0.680, 0.946, -1.832]],
device='cuda:0')
'''
示例 5：恢复默认打印选项
import torch
# 创建一个张量
tensor = torch.randn(5, 5)
# 恢复默认打印选项
torch.set_printoptions(profile='default')
# 打印张量
print(tensor)
# 设置打印选项为short
torch.set_printoptions(profile='short')
# 打印张量
print(tensor)
# 设置打印选项为full
torch.set_printoptions(profile='full')
# 打印张量
print(tensor)
'''output
tensor([[-0.4571, 0.3753, -1.5940, -0.7643, -2.1443],
[ 0.6022, -0.7247, -0.0522, 1.3891, 0.5575],
[ 0.6133, -0.4906, 0.8597, -0.7087, 2.1163],
[-0.0721, 0.7349, 1.2677, 0.8921, -0.2049],
[ 0.3666, 0.1874, 1.7164, 1.0258, -1.8709]], device='cuda:0')
tensor([[-0.46, 0.38, -1.59, -0.76, -2.14],
[ 0.60, -0.72, -0.05, 1.39, 0.56],
[ 0.61, -0.49, 0.86, -0.71, 2.12],
[-0.07, 0.73, 1.27, 0.89, -0.20],
[ 0.37, 0.19, 1.72, 1.03, -1.87]], device='cuda:0')
tensor([[-0.4571, 0.3753, -1.5940, -0.7643, -2.1443],
[ 0.6022, -0.7247, -0.0522, 1.3891, 0.5575],
[ 0.6133, -0.4906, 0.8597, -0.7087, 2.1163],
[-0.0721, 0.7349, 1.2677, 0.8921, -0.2049],
[ 0.3666, 0.1874, 1.7164, 1.0258, -1.8709]], device='cuda:0')
'''