From cd9c7b6cf7aedc945d6da440a3ba7a9368d25427 Mon Sep 17 00:00:00 2001
From: Xin Qiu <qiuxin2012@users.noreply.github.com>
Date: Fri, 13 Oct 2017 16:44:26 +0800
Subject: [PATCH] SparseLinear SparseJoinTable DenseToSparse (#1652)

* SparseLinear SparseJoinTable DenseToSparse

* Python api

* add DenseToSparseSpec

* update to upstream

* add some method

* meet code review

* fix python unit test

* fix python unit test