pivot heldout csv

eval-logs/pivot_heldout_1782710967.csv

@@ -6,3 +6,4 @@ ts_unix_s,elapsed_s,phase,docs,tokens,chars,warmup_docs_target,vocab_size,merges
 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
 1782711192,184.104,train,1200,643662,1657635,500,1056,800,3484.11,3496.19,6.518,1054.880716,1053.428468,6.961183,6.959905,10.042864,3.899658,3.886122,0.399363,573120.0,0.999905,0.999860,1.000000,1.000000,4.998988,5.739808,4.996950,4.995657,4.999091,4.996414,4.999263,0.011420,50.519602,63.327375,10.658074
 1782711223,215.258,train,1400,751930,1934334,500,1056,800,3475.21,3493.15,6.504,1054.595209,1053.007413,6.960912,6.959303,10.042474,3.903792,3.890056,0.398342,573120.0,0.999872,0.999700,1.000000,1.000000,4.999384,5.752656,4.998882,4.997632,4.995551,4.998476,4.999631,0.003303,52.351898,65.823099,10.658074
+1782711254,245.772,train,1600,858450,2206138,500,1056,800,3490.83,3492.87,6.510,1054.203591,1051.750034,6.960541,6.957919,10.041938,3.907508,3.893968,0.400133,573120.0,0.999856,0.999800,1.000000,1.000000,4.999559,5.696548,4.995145,4.996804,4.999950,4.998809,4.995947,0.009895,54.182652,68.359974,10.658074