Merge branch 'incremental_updates' into 'master'

synchronize with pocketfft C++

See merge request !43

pocketfft_hdronly.h

 /*
 This file is part of pocketfft.
 
-Copyright (C) 2010-2020 Max-Planck-Society
+Copyright (C) 2010-2021 Max-Planck-Society
 Copyright (C) 2019-2020 Peter Bell
 
 For the odd-sized DCT-IV transforms:
@@ -52,12 +52,12 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endif
 
 #include <cmath>
-#include <cstring>
 #include <cstdlib>
 #include <stdexcept>
 #include <memory>
 #include <vector>
 #include <complex>
+#include <algorithm>
 #if POCKETFFT_CACHE_SIZE!=0
 #include <array>
 #include <mutex>
@@ -1302,9 +1302,9 @@ template<bool fwd, typename T> void pass11 (size_t ido, size_t l1,
       }
   }
 
-#undef PARTSTEP11
-#undef PARTSTEP11a0
-#undef PARTSTEP11a
+#undef POCKETFFT_PARTSTEP11
+#undef POCKETFFT_PARTSTEP11a0
+#undef POCKETFFT_PARTSTEP11a
 #undef POCKETFFT_PREP11
 
 template<bool fwd, typename T> void passg (size_t ido, size_t ip,
@@ -1456,7 +1456,7 @@ template<bool fwd, typename T> void pass_all(T c[], T0 fct) const
       for (size_t i=0; i<length; ++i)
         c[i] = ch[i]*fct;
     else
-      memcpy (c,p1,length*sizeof(T));
+      std::copy_n (p1, length, c);
     }
   else
     if (fct!=1.)
@@ -2204,19 +2204,19 @@ template<typename T> void radbg(size_t ido, size_t ip, size_t l1,
     }
   }
 
-    template<typename T> void copy_and_norm(T *c, T *p1, size_t n, T0 fct) const
+    template<typename T> void copy_and_norm(T *c, T *p1, T0 fct) const
       {
       if (p1!=c)
         {
         if (fct!=1.)
-          for (size_t i=0; i<n; ++i)
+          for (size_t i=0; i<length; ++i)
             c[i] = fct*p1[i];
         else
-          memcpy (c,p1,n*sizeof(T));
+          std::copy_n (p1, length, c);
         }
       else
         if (fct!=1.)
-          for (size_t i=0; i<n; ++i)
+          for (size_t i=0; i<length; ++i)
             c[i] *= fct;
       }
 
@@ -2224,16 +2224,16 @@ template<typename T> void radbg(size_t ido, size_t ip, size_t l1,
     template<typename T> void exec(T c[], T0 fct, bool r2hc) const
       {
       if (length==1) { c[0]*=fct; return; }
-      size_t n=length, nf=fact.size();
-      arr<T> ch(n);
+      size_t nf=fact.size();
+      arr<T> ch(length);
       T *p1=c, *p2=ch.data();
 
       if (r2hc)
-        for(size_t k1=0, l1=n; k1<nf;++k1)
+        for(size_t k1=0, l1=length; k1<nf;++k1)
           {
           size_t k=nf-k1-1;
           size_t ip=fact[k].fct;
-          size_t ido=n / l1;
+          size_t ido=length / l1;
           l1 /= ip;
           if(ip==4)
             radf4(ido, l1, p1, p2, fact[k].tw);
@@ -2251,7 +2251,7 @@ template<typename T> void radbg(size_t ido, size_t ip, size_t l1,
         for(size_t k=0, l1=1; k<nf; k++)
           {
           size_t ip = fact[k].fct,
-                 ido= n/(ip*l1);
+                 ido= length/(ip*l1);
           if(ip==4)
             radb4(ido, l1, p1, p2, fact[k].tw);
           else if(ip==2)
@@ -2266,7 +2266,7 @@ template<typename T> void radbg(size_t ido, size_t ip, size_t l1,
           l1*=ip;
           }
 
-      copy_and_norm(c,p1,n,fct);
+      copy_and_norm(c,p1,fct);
       }
 
   private:
@@ -2437,13 +2437,12 @@ template<typename T0> class fftblue
           tmp[m].Set(c[m], zero);
         fft<true>(tmp.data(),fct);
         c[0] = tmp[0].r;
-        memcpy (c+1, tmp.data()+1, (n-1)*sizeof(T));
+        std::copy_n (&tmp[1].r, n-1, &c[1]);
         }
       else
         {
         tmp[0].Set(c[0],c[0]*0);
-        memcpy (reinterpret_cast<void *>(tmp.data()+1),
-                reinterpret_cast<void *>(c+1), (n-1)*sizeof(T));
+        std::copy_n (c+1, n-1, &tmp[1].r);
         if ((n&1)==0) tmp[n/2].i=T0(0)*c[0];
         for (size_t m=1; 2*m<n; ++m)
           tmp[n-m].Set(tmp[m].r, -tmp[m].i);