... free_dmatrix(irho[j],1,nn,1,nn);}free_dmatrix(irhs[1],1 ,3, 1 ,3) ;free_dmatrix(iu[1],1 ,3, 1 ,3) ;}19.6 Multigrid Methods for Boundary Value Problems8 83 Sample page from NUMERICAL RECIPES IN C: THE ART OF SCIENTIFIC COMPUTING (ISBN 0-521- 431 08-5)Copyright ... 1-800-872-74 23 (North America only),or send email to trade@cup.cam.ac.uk (outside North America).CITED REFERENCES AND FURTHER READING:Brandt, A. 1977,Mathematics of Computation, vol. 31 , pp. 33 3 39 0. ... ···=(H2−h2)τ2+O(h4)(19.6 .38 )For the usual case of H =2hwe therefore haveτ 1 3 τh1 3 τh(19.6 .39 )The stopping criterion is thus equation (19.6 .36 ) with = ατh,α∼1 3 (19.6.40)We have...