simplify

interpol_ng/demo.py

@@ -10,6 +10,14 @@ def nalm(lmax, mmax):
     return ((mmax+1)*(mmax+2))//2 + (mmax+1)*(lmax-mmax)
 
 
+def random_alm(lmax, mmax):
+    res = np.random.uniform(-1., 1., nalm(lmax, mmax)) \
+     + 1j*np.random.uniform(-1., 1., nalm(lmax, mmax))
+    # make a_lm with m==0 real-valued
+    res[0:lmax+1].imag = 0.
+    return res
+
+
 def deltabeam(lmax,kmax):
     beam=np.zeros(nalm(lmax, kmax))+0j
     for l in range(lmax+1):
@@ -24,10 +32,7 @@ kmax=2  # doesn't make any sense for the beam we are using, but just for demonst
 
 # get random sky a_lm
 # the a_lm arrays follow the same conventions as those in healpy
-slmT =      np.random.uniform(-1., 1., nalm(lmax, mmax)) \
-       + 1j*np.random.uniform(-1., 1., nalm(lmax, mmax))
-# make a_lm with m==0 real-valued
-slmT[0:lmax+1].imag = 0.
+slmT = random_alm(lmax, mmax)
 
 # build beam a_lm (pencil beam for now)
 blmT = deltabeam(lmax,kmax)

interpol_ng/interpol_ng.cc

@@ -99,25 +99,20 @@ template<typename T> class Interpolator
         {
         double spinsign = (k==0) ? 1. : -1.;
         for (size_t m=0; m<=lmax; ++m)
-          {
-          T mfac=T((m&1) ? -1.:1.);
           for (size_t l=m; l<=lmax; ++l)
             {
             if (l<k)
               a1(l,m)=a2(l,m)=0.;
             else
               {
-              complex<T> v1=slmT(l,m)*blmT(l,k),
-                         v2=conj(slmT(l,m))*blmT(l,k)*mfac;
-              a1(l,m) = (v1+conj(v2)*mfac)*T(0.5*spinsign*lnorm[l]);
+              a1(l,m) = slmT(l,m)*blmT(l,k).real()*T(spinsign*lnorm[l]);
               if (k>0)
                 {
-                complex<T> tmp = (v1-conj(v2)*mfac)*T(-spinsign*0.5*lnorm[l]);
+                complex<T> tmp = slmT(l,m)*blmT(l,k).imag()*T(-spinsign*lnorm[l]);
                 a2(l,m) = complex<T>(-tmp.imag(), tmp.real());
                 }
               }
             }
-          }
         size_t kidx1 = (k==0) ? 0 : 2*k-1,
                kidx2 = (k==0) ? 0 : 2*k;
         auto quadrant=k%4;