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Table 2 Characteristics of preconditioned (deflated) coefficient matrices, and of PCG and DPCG methods for solving ssSNPBLUP applied to the field dataset

From: A second-level diagonal preconditioner for single-step SNPBLUP

\(\text{Model}^{\mathrm{a}}\)

Method

\(k_{O}/k_{S}^{\mathrm{b}}\)

\(\lambda _{min}^{\mathrm{c}}\)

\(\lambda _{max}^{\mathrm{c}}\)

\(\kappa ^{\mathrm{d}}\)

\(\textit{N}^{\mathrm{e}}\)

\(\text{Iterative time}^{\mathrm{f}}\)

\(\text{Time/iter.}^{\mathrm{g}}\)

\(\text{Total time}^{\mathrm{h}}\)

MS

PCG

1

\(3.70\times 10^{-5}\)

\(1.75\times 10^{3}\)

\(4.74\times 10^{7}\)

10,000

44,808

4.5

46,081

MS

PCG

\(10^{-1}\)

\(1.18\times 10^{-5}\)

\(1.77\times 10^{2}\)

\(1.51\times 10^{7}\)

10,000

51,768

5.2

53,550

MS

PCG

\(10^{-2}\)

\(4.37\times 10^{-6}\)

\(1.95\times 10^{1}\)

\(4.45\times 10^{6}\)

6210

34,139

5.5

35,812

MS

PCG

\(10^{-3}\)

\(3.99\times 10^{-6}\)

5.08

\(1.27\times 10^{6}\)

3825

19,043

5.0

20,866

MS

PCG

\(10^{-4}\)

\(1.50\times 10^{-6}\)

5.07

\(3.37\times 10^{6}\)

7336

54,326

7.4

56,475

MS

DPCG

1

\(2.86\times 10^{-5}\)

4.77

\(1.67\times 10^{5}\)

748

6527

8.7

17,229

MS

DPCG

\(10^{-1}\)

\(1.41\times 10^{-5}\)

4.77

\(3.37\times 10^{5}\)

1211

11,864

9.8

22,947

MS

DPCG

\(10^{-2}\)

\(9.17\times 10^{-6}\)

4.77

\(5.20\times 10^{5}\)

1778

17,030

9.6

28,615

MS

DPCG

\(10^{-3}\)

\(7.50\times 10^{-6}\)

4.77

\(6.36\times 10^{5}\)

2569

23,676

9.2

35,497

Liu

PCG

1

\(7.38\times 10^{-6}\)

\(1.43\times 10^{2}\)

\(1.93\times 10^{7}\)

10,000

44,122

4.4

45,083

Liu

PCG

\(10^{-1}\)

\(3.66\times 10^{-6}\)

\(1.52\times 10^{1}\)

\(4.14\times 10^{6}\)

6049

31,085

5.1

32,018

Liu

PCG

\(10^{-2}\)

\(4.29\times 10^{-6}\)

5.07

\(1.18\times 10^{6}\)

2669

13,225

5.0

13,888

Liu

PCG

\(10^{-3}\)

\(3.51\times 10^{-6}\)

5.07

\(1.44\times 10^{6}\)

3606

20,578

5.7

21,458

Liu

PCG

\(10^{-4}\)

\(1.69\times 10^{-6}\)

5.07

\(3.00\times 10^{6}\)

7033

33,534

4.8

34,675

Liu

DPCG

1

\(5.40\times 10^{-6}\)

5.31

\(9.85\times 10^{5}\)

2877

22,791

7.9

26,521

Liu

DPCG

\(10^{-1}\)

\(6.91\times 10^{-6}\)

4.77

\(6.90\times 10^{5}\)

1628

14,231

8.7

18,049

Liu

DPCG

\(10^{-2}\)

\(5.23\times 10^{-6}\)

4.77

\(9.11\times 10^{5}\)

2234

23,244

10.4

28,057

Liu

DPCG

\(10^{-3}\)

\(4.31\times 10^{-6}\)

4.77

\(1.11\times 10^{6}\)

3106

34,950

11.3

39,603

  1. \({}^{\mathrm{a}}\)MS = ssSNPBLUP model proposed by Mantysaari and Stranden [7]; Liu = ssSNPBLUP model proposed by Liu et al. [5];
  2. \({}^{\mathrm{b}}\)Parameters used for the second-level preconditioner;
  3. \({}^{\mathrm{c}}\)Smallest and largest eigenvalues of the preconditioned (deflated) coefficient matrix;
  4. \({}^{\mathrm{d}}\)Condition number of the preconditioned (deflated) coefficient matrix;
  5. \({}^{\mathrm{e}}\)Number of iterations. A number of iterations equal to 10,000 means that the method failed to converge within 10,000 iterations;
  6. \({}^{\mathrm{f}}\)Wall clock time (seconds) for the iterative process;
  7. \({}^{\mathrm{g}}\)Average wall clock time (seconds) per iteration;
  8. \({}^{\mathrm{h}}\)Wall clock time (seconds) for a complete process (including I/O operations)