如何在sympy中舍入矩阵元素

Question

正如我们所知

from sympy import *
x = sin(pi/4)
y = sin(pi/5)
A = Matrix([x, y])
print(x)
print(A.evalf())

显示

sqrt(2)/2
Matrix([[0.707106781186548], [0.587785252292473]])

所以

print(round(x.evalf(), 3))
print(round(y.evalf(), 3))

显示

0.707
0.588

但是，我们如何才能以简洁的方式将矩阵中的所有元素取整，从而使

print(roundMatrix(A, 3))

可以显示

Matrix([[0.707], [0.588]])

Answer 1

为什么不将方法evalf与evalf(3)等参数一起使用？

from sympy import *
x = sin(pi/4)
y = sin(pi/5)
A = Matrix([x, y])
print(x)
print(A.evalf(3))

输出

sqrt(2)/2
Matrix([[0.707], [0.588]])

Answer 2

这适用于我的

# Z is a matrix
from functools import partial
round3 = partial(round, ndigits=3)
Z.applyfunc(round3)
# if you want to save the result
# Z = Z.applyfunc(round3)

Answer 3

from sympy import *
roundMatrix = lambda m, n: Matrix([[round(m[x, y], n) for y in range(m.shape[1])] for x in range(m.shape[0])])
x = sin(pi/4)
y = sin(pi/5)
A = Matrix([x, y])
print(x)
print(roundMatrix(A.evalf(), 3))`