## Singular matrix issue with Numpy

I am trying to multiply a vector(3 by 1) by its transpose(1 by 3). I get a (3 by 3) array but I cannot get its inverse. Any idea why?

import numpy as np c=array([1, 8, 50]) np.transpose(c[np.newaxis]) * c array([[ 1, 8, 50], [ 8, 64, 400], [ 50, 400, 2500]]) np.linalg.inv(np.transpose(c[np.newaxis]) * c) Traceback (most recent call last): File "<console>", line 1, in <module> File "C:\Python26\lib\site-packages\numpy\linalg\linalg.py", line 445, in inv return wrap(solve(a, identity(a.shape[0], dtype=a.dtype))) File "C:\Python26\lib\site-packages\numpy\linalg\linalg.py", line 328, in solve raise LinAlgError, 'Singular matrix' LinAlgError: Singular matrix

The matrix you pasted

[[ 1, 8, 50], [ 8, 64, 400], [ 50, 400, 2500]]

Has a determinant of zero. This is the definition of a Singular matrix (one for which an inverse does not exist)

http://en.wikipedia.org/wiki/Invertible_matrix

**Singular matrix issue with Numpy,** The matrix you pasted: [[ 1, 8, 50],. [ 8, 64, 400],. [ 50, 400, 2500]]. Has a determinant of zero. This is the definition of a Singular matrix (one for� @sparseinference Matlab correctly identifies this as singular and gives me a matrix of Infs, but it does return a "non-zero" determinant of -3.0815e-33. My guess is it's just a question of a different BLAS implementation, and as @certik mentions, the usual issues surrounding floating point operations.

By definition, by multiplying a 1D vector by its transpose, you've created a singular matrix.

Each row is a linear combination of the first row.

Notice that the second row is just 8x the first row.

Likewise, the third row is 50x the first row.

There's only one independent row in your matrix.

**Inverse of singular matrix. Should be error but in fact not. � Issue ,** 2, numpy version '1.13.3' and '1.14.0'. PS. I've checked via wolfram and R it's real singular matrix. Singular matrix issue with Numpy +1 vote . 1 view. asked Jul 31, 2019 in Python by Eresh Kumar (29.4k points) I am trying to multiply a vector(3 by 1) by its

As it was already mentioned in previous answers, your matrix cannot be inverted, because its determinant is 0.
But if you still want to get inverse matrix, you can use `np.linalg.pinv`

, which leverages SVD to approximate initial matrix.

**np.linalg.inv doesn't throw error on singular matrix inversion � Issue ,** but np.linalg.inv does not throw an error as expected (because said matrix is singular) Reproducing code example: import numpy as np a� "Is this matrix singular?" is numerically ill-posed and a better question is "How close is this matrix to the set of singular matrices?" which is answered by the reciprocal of the matrix condition number, which can be found with np.linalg.cond. Furthermore, the question of numerical rank is also ill-posed and a better question is "How close is

Use SVD or QR-decomposition to calculate exact solution in real or complex number fields:

numpy.linalg.svd numpy.linalg.qr

**Numpy singular matrix error when trying to use Newton's method ,** Numpy singular matrix error when trying to use Newton's method. I am trying to This still would not eliminate the problem of frequent posts. I'm thinking at the� it is returning File "C:\PYTHON23\Lib\site-packages\numpy\linalg\linalg.py", line 138, in solve raise LinAlgError, 'Singular matrix' numpy.linalg.linalg.LinAlgError: Singular matrix Does anyone know what I am doing wrong? -Kenny

**Singular Matrices,** The problem is, if we ever need to invert a singular matrix we are in big trouble! import numpy as np arr = np.array([ [16, 2, 3, 13], [5, 11, 10, 8], [9, 7, 6, 12], [4,� The DIIS matrix occasionally becomes singular. A matrix causing this bug looks like ``` 5.33626410759e-10 5.33626410757e-10 5.33626410759e-10 -1.0 5.33626410757e-10 5.33626410757e-10 5.33626410761e-10 -1.0 5.33626410759e-10 5.33626410761e-10 5.33626410766e-10 -1.0 -1.0 -1.0 -1.0 0.0

**numpy.matrix.I — NumPy v1.20.dev0 Manual,** Next topic. numpy.matrix.A property matrix. self is non-singular, ret is such that ret * self == self * ret == np.matrix(np.eye(self[0 LinAlgError: Singular matrix . Parameters ----- a : (M, M) array_like Square matrix b : (M, N) array_like Input q : (M, M) array_like Input r : (N, N) array_like Nonsingular square matrix e : (M, M) array_like, optional Nonsingular square matrix s : (M, N) array_like, optional Input balanced : bool, optional The boolean that indicates whether a balancing step is performed on

**numpy.linalg.pinv — NumPy v1.9 Manual,** Calculate the generalized inverse of a matrix using its singular-value decomposition is defined as: “the matrix that 'solves' [the least-squares problem ] Ax = b� numpy.matrix is matrix class that has a more convenient interface than numpy.ndarray for matrix operations. This class supports, for example, MATLAB-like creation syntax via the semicolon, has matrix multiplication as default for the * operator, and contains I and T members that serve as shortcuts for inverse and transpose:

##### Comments

- Happens also if you raise the matrix to a negative power.
- Can you elaborate more?
- SVD is singular value decomposition (en.wikipedia.org/wiki/Singular_value_decomposition). And pinv is a pseudoinverse (en.wikipedia.org/wiki/…, en.wikipedia.org/wiki/Moore%E2%80%93Penrose_inverse).