Add missing cmath header (#287)
Add missing cmath header (#287)

f9ed337552a26cc55c7c0fb22cd54839ee13f19c added a call to std::log
without including cmath
sxjscience/tvm,Laurawly/tvm-1,Laurawly/tvm-1,tqchen/tvm,tqchen/tvm,Laurawly/tvm-1,Laurawly/tvm-1,sxjscience/tvm,Huyuwei/tvm,tqchen/tvm,dmlc/tvm,Laurawly/tvm-1,tqchen/tvm,sxjscience/tvm,Huyuwei/tvm,Laurawly/tvm-1,tqchen/tvm,dmlc/tvm,Huyuwei/tvm,Huyuwei/tvm,sxjscience/tvm,tqchen/tvm,Huyuwei/tvm,Laurawly/tvm-1,tqchen/tvm,Huyuwei/tvm,sxjscience/tvm,dmlc/tvm,sxjscience/tvm,Huyuwei/tvm,dmlc/tvm,tqchen/tvm,dmlc/tvm,Laurawly/tvm-1,Laurawly/tvm-1,dmlc/tvm,sxjscience/tvm,Huyuwei/tvm,tqchen/tvm,sxjscience/tvm,dmlc/tvm,sxjscience/tvm,dmlc/tvm,dmlc/tvm,Laurawly/tvm-1,Huyuwei/tvm,tqchen/tvm