fixed default batch size
fixed default batch size

[git-p4: depot-paths = "//sw/gpgpu/nvbio/main/": change = 18866183]

NVlabs/nvbio,kimrutherford/nvbio,NVlabs/nvbio,kimrutherford/nvbio,kimrutherford/nvbio,kimrutherford/nvbio,NVlabs/nvbio,NVlabs/nvbio