Acces and store the negative m SH coefficents

[Former user]

Hello,

I am trying to initialize an array for a given set of l and m SH coefficients, with m going from -l to +l. I saw that the way the negative m coefficients are stored is through the complex conjugate. However, I do not understand how I can access such values and rewrite them in a way that the posterior transformation to grid uses all the coefficients, positive and negative.

Could you help me with that?

Thank you so much for your time :) B

[Nathanaël Schaeffer]

For real-valued spatial fields, the negative m’s are not stored. For complex-valued spatial fields they are stored and accessible. It is explained here: https://nschaeff.bitbucket.io/shtns/spec.html#spat_cplx
From python, use the synth_cplx and analys_cplx methods.