Fix bug in handling of first element.

src/ppm/ppm_m1d.f90

@@ -319,7 +319,8 @@ CONTAINS
     CALL assertion(np == SIZE(em), msg=context//': np /= SIZE(em)')
 
     IF (pload(1) < 0.0_dp) THEN
-      DO ip=1,np
+      pload(1) = SUM(wload(1:em(1)))
+      DO ip=2,np
         pload(ip)=SUM(wload(em(ip-1)+1:em(ip)))
       ENDDO
     ENDIF