Getting linalg error:: 1-dimensional array given. Array must be at least two-dimensional

Question

a = array([[2*R0*(Q0**2), 2*R1*(Q1**2), 2*R2*(Q2**2), 2*R3*(Q3**2), 2*R4*(Q4**2), 0, 0, 0],
       [0, 0, 0, 2*R3*(Q3**2), 2*R4*(Q4**2), 0, 0, 0], [0, 2*R1*(Q1**2),0, 0, 0,  2*R5*(Q5**2), 2*R6*(Q6**2), 2*R7*(Q7**2)], [1, 1, 0, 0, 0, 0, 1], [0, 1, 1, 0, 0, 1, 0, 0, 0], [0, 0, 1, 1, 1, 0, 0, 0],
       [0, 0, 0, 0, 0, 1, 0, 1], [0, 0, 0, 0, 0, 0, 0, 1, 1]])

b = array([[95-(R0*(Q0**3))-(R1*(Q1**3))-(R2*(Q2**3))-(R3*(Q3**3))-(R4*(Q4**3))], [-(R4*(Q4**3))-(R3*(Q3**3))],
        [-(R6*(Q6**3))-(R7*(Q7**3))-(R1*(Q1**3))-(R5*(Q5**3))], [-Q0+Q1+Q6], [0.6-Q1+Q2+Q5], [-Q2+Q3+Q4], [1.4-Q7-Q5], [Q7-Q6]])

p = solve(a, b)

print ("deltaQ:", p)

Solve (a,b) is a gauss jordan elimination function that solves linear equations where R0-R7 AND Q0-Q7 ARE CONSTANTS! It works with other matrices, however for this one i get an error.

Maybe a = np.matrix(a) and b=np.matrix(b)

Allan Karlson
– Allan Karlson

2017-07-07 08:52:49 +00:00
Commented Jul 7, 2017 at 8:52 — Allan Karlson
– Allan Karlson, Commented Jul 7, 2017 at 8:52

percusse · Accepted Answer · 2015-10-16 07:02:57Z

1

the array a doesn't have consistent rows hence numpy initializes the array as 1D array holding different "objects" instead of 2D array.

>>>> print(a.dtype)
object

Hence the error complaining about not having 2D array but only 1D.

answered Oct 16, 2015 at 7:02

percusse

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MrKickass · Accepted Answer · 2018-04-16 06:38:12Z

0

When I faced this issue, it was regarding eigen vector generation for a laplacian matrix which was a sparse matrix. I had to use laplacian_matrix.todense() function( laplacian_matrix is from package networkx) and the exception got resolved.

answered Apr 16, 2018 at 6:38

MrKickass

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