Math5.0 frustrated Compatibility Problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg56932] Math5.0 frustrated Compatibility Problem*From*: "Jingming Yao" <jingming_yao at hotmail.com>*Date*: Tue, 10 May 2005 03:42:48 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hello Everyone There is a very interesting problem. I have a 4 equations 4 knowns nonlinear algebra equation system. It CAN be solved by Math 4.1 or 4.2 but it can NOT be solved by Math 5.0. It is the same program. And the error message in Math 5.0 is "FindRoot:: jsing: Encountered a singular Jacobian at the point {p02n, ?¢Vb2n, n02n, JCn, ?Àn}={2.9*10^18, 0.61, 3.7*10^11, 0.5}. Try perturbing the initial point(s)." My program is as follows. u2 = d0 - ((Cb*( zVb2 - ?¢Vb2n))/(q*Ns02) + q*Lz*(p02n)/(q*Ns02) + (ϵ/d)*(z?³s + ?¢?³sn)/(q* Ns02)); u4 = JBp - Jpe0*((p02n/zp02)* Exp[-?¢?³sn/VT] - 1) - Jpb0*(( p02n/zp02)*Exp[(?¢Vb2n)/VT] - 1) - Jrc0*(?ã(p02n/ zp02)*Exp[-?¢?³sn/(2*VT)] - 1) - Jrb0*(?ã(p02n/zp02)*Exp[(?¢Vb2n)/(2*VT)] - 1) - q*A*Lz*p02n*n02n; u6 = ?¢?³sn - (1 - ?¢Vb2n); u12 = n02n*q*Vn*Exp[-?³emc2/VT] + n02n*q*Vn*Exp[-?³eme2/VT] + q*A*Lz*p02n*n02n + (n02n*p02n/(n02n + p02n))*(q*Lz)/?ÑNR - (?Ánc* Jnc0*(Exp[(?¢Vb2n)/VT] - 1) + ?Áne*Jne0*(Exp[-?¢?³sn/VT] - 1)); JBp = 0.001; Answer[i] = FindRoot[{u2, u4, u6, u12}, {p02n, 2.9*10^18}, {?¢Vb2n, 0.61}, { n02n, 3.7*10^11}, {?¢?³sn, 0.5}] The starting values I use above are close to answers Math 4.1 gives me. All the others are constants with values like d0 = 8*10^-7; d = 5*10^-5; ϵ = 13.1*8.854*10^-14; db = 2.5*10^-6; Cb = ϵ/db; zVb2 = 0.843; q = 1.60218*10^-19; Ns02 = 3.2*10^18; Lz = 6*10^-7; Jpe0 = 6.29*10^-19; zp02 = 4*10^9; z?³s = 0.806; VT = 0.0259; Jpb0 = 1.6*10^-29; Jrc0 = 1.065*10^-10; Jrb0 = 5.33*10^-12; A = 10^-10; Vn = 10^7; ?³emc2 = 0.43; ?³eme2 = 0.446; ?ÑNR = 10^-9; ?Ánc = 0.001; ?Áne = 0.001; Jnc0 = 2.57*10^-10; Jne0 = 2.57*10^-10; ?³sn = z?³s + ?¢?³sn; Anybody has some idea? Thnaks a lot. Jingming Uconn, ECE Dept. Graduate Assistance _________________________________________________________________ FREE pop-up blocking with the new MSN Toolbar ? get it now! http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/

**Follow-Ups**:**Re: Math5.0 frustrated Compatibility Problem***From:*Chris Chiasson <chris.chiasson@gmail.com>

**Re: Math5.0 frustrated Compatibility Problem***From:*DrBob <drbob@bigfoot.com>