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►2 in Abramowitz and Stegun (1964) gives values of , , and to 7 or 8D in the rectangular and rhombic cases, normalized so that and (rectangular case), or and (rhombic case), for = 1.
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►where and the square roots are real and positive when the lattice is rectangular; otherwise they are determined by continuity from the rectangular case.
the nome,
, . Since is not a single-valued
function of , it is assumed that is known, even when
is specified. Most applications concern the rectangular case
, , so that and
and are uniquely related.
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►Abramowitz and Stegun (1964, Chapter 18) considers only rectangular and rhombic lattices (§23.5); , are replaced by , for the former and by , for the latter.
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►Lines parallel to the real axis in the -plane map onto ellipses in the -plane with foci at , and lines parallel to the imaginary axis in the -plane map onto rectangular hyperbolas confocal with the ellipses.
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