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By : user2171848
Date : October 25 2020, 09:10 AM
To fix this issue In what environment are you running this? With Windows command line I get: code :
``````>>> x = Matrix(4, 3, range(12))
>>> r=x.applyfunc(lambda e:
... Decimal(str(round(e+.2,1))).quantize(Decimal('.01'),
... rounding=ROUND_HALF_UP))
>>> r
0.200000000000000
>>> r
Matrix([
[0.2,  1.2,  2.2],
[3.2,  4.2,  5.2],
[6.2,  7.2,  8.2],
[9.2, 10.2, 11.2]])
>>> r.round(1)
0.2
`````` ## How to take element-wise logarithm of a matrix in sympy?

By : Lucas Barbosa Fonsec
Date : March 29 2020, 07:55 AM
wish helps you Working with a sympy Matrix or numpy array of sympy symbols, how does one take the element-wise logarithm? , Use Matrix.applyfunc:
code :
``````In : M = sympy.Matrix(sympy.symbols('a b c d'))

In : M.applyfunc(sympy.log)
Out:
⎡log(a)⎤
⎢      ⎥
⎢log(b)⎥
⎢      ⎥
⎢log(c)⎥
⎢      ⎥
⎣log(d)⎦
`````` ## How to derive with respect to a Matrix element with Sympy

By : gochobot
Date : March 29 2020, 07:55 AM
seems to work fine Given the product of a matrix and a vector , The git version of SymPy (and the next version) handles this better:
code :
``````In : print(diff(C[l,h], A[i,j]))
Sum(KroneckerDelta(_k, j)*KroneckerDelta(i, l)*B[_k, h], (_k, 0, m - 1))
`````` ## In python sympy, how do I apply an external python funtion to each element of the sympy matrix?

By : mygodccl
Date : March 29 2020, 07:55 AM
hop of those help? To be more specific, I want to apply the following sigmoid function:
code :
``````>>> M.applyfunc(sigmoid)

Matrix([
[1/(exp(-1) + 1), 1/(exp(-3) + 1)],
[1/(exp(-2) + 1), 1/(exp(-4) + 1)]])
``````
``````class sigmoid(Function):
pass
``````
``````>>> M.applyfunc(sigmoid)
Matrix([
[sigmoid(1), sigmoid(3)],
[sigmoid(2), sigmoid(4)]])
`````` ## How to round Matrix sqrtm in sympy?

By : TsG134
Date : March 29 2020, 07:55 AM
wish helps you After calling sqrtm type of matrix changed and you can not use evalf:
A:
code :
``````from sympy import *
from mpmath import *
A=Matrix([[5,4,1],
[4,6,4],
[1,4,5]])
print(A)
B=sqrtm(A)
print(chop(B))
``````
``````[2.0  1.0  0.0]
[1.0  2.0  1.0]
[0.0  1.0  2.0]
`````` ## How to round Matrix elements in sympy?

By : hghtms
Date : March 29 2020, 07:55 AM
To fix this issue As we know , Why you do not use method evalf with args like evalf(3)?
code :
``````from sympy import *

x = sin(pi/4)
y = sin(pi/5)

A = Matrix([x, y])

print(x)
print(A.evalf(3))
``````
``````sqrt(2)/2
Matrix([[0.707], [0.588]])
`````` 