Add data to test the let construction

experimental/data/prolate.fma

+8  3  3  0
+20   2   0  0  0
+0.0809031230504549    1.79162592115318    -0.885173001922618    
+-0.867067587846295    -1.38222706284923    -1.15656480355992    
+-0.385613214189926    -1.47295401481943    1.29680720204255    
+-0.750199973748544    0.192147892218982    -1.84398459508302    
+0.960043029523525    1.47342455495335    0.952542630187134    
+1.70125586227436    -0.948164415762297    0.454656718590267    
+-0.521997577607621    1.92186342242525    0.184281074762649    
+-1.82954540778678    -0.454566815919891    0.667931591340569    
+1.44356330102518    -0.112090519195825    1.37969587643064    
+-0.510260872125445    -1.28128708221142    -1.44842578523579    
+0.748341921129961    -1.5507485760366    1.01742971403433    
+-0.208624790292834    -1.17488981534778    1.60502636073908    
+-1.73772516642285    -0.719849706910965    -0.67979970979757    
+-0.97760433288891    -1.63498542635483    0.609189973591282    
+-1.78667745739927    0.872448799264151    0.215909138027594    
+0.238576211363531    -1.9803677622189    0.145687740512089    
+1.06232571660996    -1.33517178035395    -1.04344639956999    
+-0.966184374559756    0.561993211440958    1.65850878341082    
+1.40002072917679    1.40803292340081    0.239552174890255    
+0.983775132226723    1.65504198877585    0.541315531461237    

experimental/examples/test-build-let.cpp

@@ -22,7 +22,9 @@
 /// \param argv
 /// \return
 ///
+///
 /// ./examples/RelWithDebInfo/test-build-let --input-file ../data/prolate.fma  --order 3 --tree-height 4 --group-size 3
+///   mpirun --oversubscribe -np 3 ./examples/RelWithDebInfo/test-build-let --input-file ../buildMPI/prolate.fma  --order 3 --tree-height 4 --group-size 3
 
 auto main([[maybe_unused]] int argc, [[maybe_unused]] char* argv[]) -> int
 {