[Solved] What is wrong with this code?from scipy.sparse.linalg import gmres import numpy as np A = np.array([[1,2],[3,4]]) b = np.array([5,6]) x = gmres(A, b) print(x) | SciPy

SciPy - Sparse Linear Algebra

What is wrong with this code?

from scipy.sparse.linalg import gmres
import numpy as np
A = np.array([[1,2],[3,4]])
b = np.array([5,6])
x = gmres(A, b)
print(x)

AMatrix A is not sparse

BVector b is not a list

Cgmres returns a tuple, but code expects a single value

DImport statement is missing

Step-by-Step Solution

Solution:

Step 1: Check gmres return values
gmres returns a tuple (solution vector, info flag), not a single value.
Step 2: Identify the error in assignment
Assigning gmres(A, b) to x alone causes x to be a tuple, which may confuse print output.
Final Answer:
gmres returns a tuple, but code expects a single value -> Option C
Quick Check:
gmres returns (x, info) tuple [OK]

Quick Trick: Always unpack gmres output as x, info = gmres(...) [OK]

Common Mistakes:

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What is wrong with this code?