Sparse iterative solvers (gmres, cg) in SciPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the GMRES solver from scipy.

SciPy

from scipy.sparse.linalg import [1]

Drag options to blanks, or click blank then click option'

Acg

Bgmres

Csolve

Dinv

Attempts:

3 left

💡 Hint

Common Mistakes

Importing 'cg' instead of 'gmres'.

Trying to import 'solve' which is not an iterative solver.

Using 'inv' which is for matrix inversion.

The GMRES solver is imported from scipy.sparse.linalg as gmres.

2fill in blank

medium

Complete the code to solve a linear system using the CG solver.

SciPy

x, info = [1](A, b)

Drag options to blanks, or click blank then click option'

Asolve

Binv

Cgmres

Dcg

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'solve' which is a direct solver, not iterative.

Using 'inv' which computes matrix inverse.

Using 'gmres' which is a different iterative solver.

The CG solver is called by cg(A, b) to solve the system Ax = b.

3fill in blank

hard

Fix the error in the code to correctly call GMRES with a restart parameter of 50.

SciPy

x, info = gmres(A, b, restart=[1])

Drag options to blanks, or click blank then click option'

A50

B'50'

Crestart

DNone

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the restart value as a string.

Passing the parameter name as a value.

Passing None which disables restart.

The restart parameter must be an integer, so use 50 without quotes.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps each word to its length if the length is greater than 3.

SciPy

{word: [1] for word in words if [2]

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Alen(word)

Blen(word) > 3

Cword.startswith('a')

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using the word itself as the value instead of its length.

Using a wrong condition like startswith instead of length check.

Not using a condition at all.

The dictionary comprehension maps each word to its length using len(word) and filters words with length greater than 3 using len(word) > 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase keys to values where values are greater than zero.

SciPy

result = [1]: [2] for [3], [2] in data.items() if [2] > 0}

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Ak.upper()

Bv

Ck

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable names in the loop.

Not converting keys to uppercase.

Using incorrect variable names for values.

The comprehension uses k.upper() as keys, v as values, and iterates over k, v in data.items(). It filters values greater than zero.