We develop a non planar topological vertex formalism and we use it to study
the A-model partition function Ztop of topological string on the
class of toric Calabi-Yau threefolds (CY3) in large complex structure limit. To
that purpose, we first consider the T2×R special Lagrangian
fibration of generic CY3-folds and we give the realization of the class of
large μ toric CY3-folds in terms of supersymmetric gauged linear sigma
model with \emph{non zero} gauge invariant superpotentials ). Then, we focus on a one complex parameter supersymmetric U(1) gauged
model involving six chiral superfields Φi with W=μ(∏i=05Φi) and we use it to compute the function
Ztop for the case of the local elliptic curve in the limit μ→∞.Comment: Latex, 38 pages, 12 figures. To appear in Nucl Phys