The first three iterative solvers are based on the conjugate gradient (CG) method. The first of these three CG solvers is the Jacobi Conjugate Gradient (JCG) solver (Mahinthakumar and Hoole(144)) (chosen with the EQSLV,JCG command) which is suitable for well-conditioned problems. Well-conditioned problems often arise from heat transfer, acoustics, magnetics and solid 2-D / 3-D structural analyses. The JCG solver is available for real and complex symmetric and unsymmetric matrices. The second solver is the Preconditioned Conjugate Gradient (PCG) solver (chosen with the EQSLV,PCG command) which is efficient and reliable for all types of analyses including the ill-conditioned beam/shell structural analysis. The PCG solver is made available through a license from Computational Applications and System Integration, Inc. of Champaign, Illinois (USA). The PCG solver is only valid for real symmetric stiffness matrices. The third solver is the Incomplete Cholesky Conjugate Gradient (ICCG) solver (internally developed, unpublished work) (chosen with the EQSLV,ICCG command). The ICCG solver is more robust than the JCG solver for handling ill-conditioned matrices. The ICCG solver is available for real and complex, symmetric and unsymmetric matrices.