一種用於查詢整數關係的演算法，其執行時間受實變數數量的多項式限制 (Ferguson and Bailey 1992)。遺憾的是，它在數值上不穩定，因此需要極高的數值精度。這種不穩定性的原因尚不清楚，但據信源於其對 Gram-Schmidt 正交化的依賴 (Ferguson and Bailey 1992)，而 Gram-Schmidt 正交化已知在數值上不穩定 (Golub and Van Loan 1989)。
Ferguson, H. R. P. and Bailey, D. H. "A Polynomial Time, Numerically Stable Integer Relation Algorithm." RNR Techn. Rept. RNR-91-032, Jul. 14, 1992.Ferguson, H. R. P.; Bailey, D. H.; and Arno, S. "Analysis of PSLQ, An Integer Relation Finding Algorithm." Math. Comput.68, 351-369, 1999.Golub, G. H. and Van Loan, C. F. Matrix Computations, 3rd ed. Baltimore, MD: Johns Hopkins, 1996.Hastad, J.; Just, B.; Lagarias, J. C.; and Schnorr, C. P. "Polynomial Time Algorithms for Finding Integer Relations Among Real Numbers." SIAM J. Comput.18, 859-881, 1988.Rössner, C. and Schnorr, C. P. "A Stable Integer Relation Algorithm." Tech. Rep. TR-94-016. FB Mathematik/Informatik, Universität Frankfurt, 1-11, 1994.
