Table 1 Computing times and errors for the toy brain test problem. The output W is compared to truth and a rank 140 reference solution

CPU time (sec.)

0.0396

0.1554

0.9653

2.6398

3.1108

\(\mathcal{E}(W,W_{140})\)

3.2324e−01

5.5407e−02

1.4162e−02

1.2125e−03

3.1549e−04

\(\mathcal{E}(W,W_{\mathrm{true}})\)

2.9418e−01

7.9921e−02

7.1537e−02

6.9777e−02

6.9821e−02

\(\mathcal{E}_{\mathrm{rel}}(W, W_{140})\)

4.3320e−01

8.9700e−02

2.4900e−02

2.5000e−03

5.1300e−04

\(\mathcal{E}_{\mathrm{rel}}(W,W_{\mathrm{true}})\)

4.0130e−01

1.1410e−01

1.0350e−01

1.0040e−01

1.0040e−01