| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465 |
- from __future__ import division, print_function, absolute_import
- import numpy as np
- from numpy.testing import assert_equal, assert_allclose, assert_
- from scipy.sparse.linalg.isolve import minres
- import pytest
- from pytest import raises as assert_raises
- from .test_iterative import assert_normclose
- def get_sample_problem():
- # A random 10 x 10 symmetric matrix
- np.random.seed(1234)
- matrix = np.random.rand(10, 10)
- matrix = matrix + matrix.T
- # A random vector of length 10
- vector = np.random.rand(10)
- return matrix, vector
- def test_singular():
- A, b = get_sample_problem()
- A[0, ] = 0
- b[0] = 0
- xp, info = minres(A, b)
- assert_equal(info, 0)
- assert_normclose(A.dot(xp), b, tol=1e-5)
- @pytest.mark.skip(reason="Skip Until gh #6843 is fixed")
- def test_gh_6843():
- """check if x0 is being used by tracing iterates"""
- A, b = get_sample_problem()
- # Random x0 to feed minres
- np.random.seed(12345)
- x0 = np.random.rand(10)
- trace = []
- def trace_iterates(xk):
- trace.append(xk)
- minres(A, b, x0=x0, callback=trace_iterates)
- trace_with_x0 = trace
- trace = []
- minres(A, b, callback=trace_iterates)
- assert_(not np.array_equal(trace_with_x0[0], trace[0]))
- def test_shift():
- A, b = get_sample_problem()
- shift = 0.5
- shifted_A = A - shift * np.eye(10)
- x1, info1 = minres(A, b, shift=shift)
- x2, info2 = minres(shifted_A, b)
- assert_equal(info1, 0)
- assert_allclose(x1, x2, rtol=1e-5)
- def test_asymmetric_fail():
- """Asymmetric matrix should raise `ValueError` when check=True"""
- A, b = get_sample_problem()
- A[1, 2] = 1
- A[2, 1] = 2
- with assert_raises(ValueError):
- xp, info = minres(A, b, check=True)
|
