pivot heldout csv

eval-logs/pivot_heldout_1782710967.csv

@@ -3,3 +3,4 @@ ts_unix_s,elapsed_s,phase,docs,tokens,chars,warmup_docs_target,vocab_size,merges
 1782711068,60.503,warmup,400,212295,548155,500,1056,800,3506.50,3508.85,6.611,1055.674471,1056.000000,6.961935,6.962243,10.043949,3.889922,3.875133,0.401929,573120.0,0.999934,1.000000,1.000000,1.000000,12.223331,30.823565,19.984896,17.872857,15.063689,4.997387,4.997382,8.170910,36.883403,45.925801,10.658074
 1782711099,91.077,train,600,318866,821747,500,1056,800,3485.61,3501.05,6.588,1055.757944,1055.838539,6.962014,6.962172,10.044063,3.897441,3.883490,0.399535,573120.0,0.999956,1.000000,1.000000,1.000000,5.018766,12.577772,8.854297,7.391411,6.457283,4.999364,4.999096,7.953214,44.153114,55.024004,10.658074
 1782711130,122.275,train,800,427853,1101436,500,1056,800,3493.38,3499.10,6.543,1055.437073,1054.341743,6.961710,6.960821,10.043625,3.901448,3.887158,0.400426,573120.0,0.999935,0.999800,1.000000,1.000000,4.996144,5.624812,4.995505,4.998764,4.996831,4.997303,4.997455,2.098739,46.764799,58.369433,10.658074
+1782711161,153.114,train,1000,535689,1379448,500,1056,800,3496.81,3498.64,6.531,1055.152415,1053.840729,6.961441,6.960370,10.043236,3.900148,3.886545,0.400818,573120.0,0.999910,0.999880,1.000000,1.000000,4.996905,5.670250,4.997390,4.999628,4.997099,4.995104,4.998678,0.007520,48.651989,60.837347,10.658074