我正在使用 Python 进入 Bokeh 库，但遇到了一些麻烦。我有来自 Bokeh 教程网站的以下代码：
from bokeh.plotting import figure
from bokeh.io import output_notebook, show
output_notebook()
from bokeh.sampledata.autompg import autompg
from bokeh.models import HoverTool
from bokeh.plotting import ColumnDataSource
grouped = autompg.groupby("yr")
mpg2 = grouped["mpg"]
avg = mpg2.mean()
std = mpg2.std()
years = list(grouped.groups.keys())
american = autompg[autompg["origin"]==1]
japanese = autompg[autompg["origin"]==3]
p = figure(title="MPG by Year (Japan and US)")
p.vbar(x=years, bottom=avg-std, top=avg+std, width=0.8,
fill_alpha=0.2, line_color=None, legend="MPG 1 stddev")
p.circle(x=japanese["yr"], y=japanese["mpg"], size=10, alpha=0.5,
color="red", legend="Japanese")
p.triangle(x=american["yr"], y=american["mpg"], size=10, alpha=0.3,
color="blue", legend="American")
p.legend.location …我正在尝试在sage中实现一些东西,并且我不断收到以下错误:
*Error in lines 38-53
Traceback (most recent call last):
File "/projects/42e45a19-7a43-4495-8dcd-353625dfce66/.sagemathcloud/sage_server.py", line 879, in execute
exec compile(block+'\n', '', 'single') in namespace, locals
File "", line 13, in <module>
File "sage/modules/vector_integer_dense.pyx", line 185, in sage.modules.vector_integer_dense.Vector_integer_dense.__setitem__ (build/cythonized/sage/modules/vector_integer_dense.c:3700)
raise ValueError("vector is immutable; please change a copy instead (use copy())")
ValueError: vector is immutable; please change a copy instead (use copy())*
我已经确定了确切位置(末尾的while循环中"print'标记1'"和"print'标记2'"之间的界限,见下面的代码)似乎我不允许更改循环内部矩阵"权重"(我在循环之前定义)的条目.错误消息说使用copy()函数,但我不知道如何解决我的问题,因为我只会制作一个本地副本,循环的下一次迭代不会得到这些更改的值,对吧？那么有谁知道如何定义这个矩阵,以便我可以从循环内部改变它？如果不可能,有人可以解释原因吗？
谢谢你的帮助.
码:
m = 3 # Dimension of inputs to nodes
n = 1 # Dimension of output
v = 4 …