Add support for absolute opeartion (#1406)

docs/api/python/intrin.rst

@@ -14,7 +14,7 @@ tvm.intrin
    tvm.ceil
    tvm.trunc
    tvm.round
-
+   tvm.abs
 
 .. autofunction:: tvm.call_packed
 .. autofunction:: tvm.call_pure_intrin
@@ -26,3 +26,4 @@ tvm.intrin
 .. autofunction:: tvm.ceil
 .. autofunction:: tvm.trunc
 .. autofunction:: tvm.round
+.. autofunction:: tvm.abs

docs/api/python/topi.rst

@@ -13,6 +13,7 @@ List of operators
    topi.ceil
    topi.trunc
    topi.round
+   topi.abs
    topi.exp
    topi.tanh
    topi.log
@@ -84,6 +85,7 @@ topi
 .. autofunction:: topi.ceil
 .. autofunction:: topi.trunc
 .. autofunction:: topi.round
+.. autofunction:: topi.abs
 .. autofunction:: topi.exp
 .. autofunction:: topi.tanh
 .. autofunction:: topi.log

docs/nnvm_top.rst

@@ -79,6 +79,7 @@ This level enables typical convnet models.
    nnvm.symbol.ceil
    nnvm.symbol.round
    nnvm.symbol.trunc
+   nnvm.symbol.abs
    nnvm.symbol.leaky_relu
    nnvm.symbol.__add_scalar__
    nnvm.symbol.__sub_scalar__
@@ -157,6 +158,7 @@ Detailed Definitions
 .. autofunction:: nnvm.symbol.ceil
 .. autofunction:: nnvm.symbol.round
 .. autofunction:: nnvm.symbol.trunc
+.. autofunction:: nnvm.symbol.abs
 .. autofunction:: nnvm.symbol.leaky_relu
 .. autofunction:: nnvm.symbol.__add_scalar__
 .. autofunction:: nnvm.symbol.__sub_scalar__

include/tvm/ir_operator.h

@@ -18,7 +18,6 @@ using HalideIR::likely_if_innermost;
 using HalideIR::cast;
 using HalideIR::min;
 using HalideIR::max;
-using HalideIR::abs;
 using HalideIR::select;
 
 /*!
@@ -71,6 +70,26 @@ inline Expr pow(Expr x, Expr y) {
   return ir::Call::make(x.type(), "pow", { x, y }, ir::Call::PureIntrinsic);
 }
 
+/*!
+ * \brief Calculate absolute value of x, elementwise
+ * \param x The input data
+ *
+ * \return The aboslute value of input data x
+ */
+inline Expr abs(Expr x) {
+  if (x.type().is_int()) {
+    return select(x >= make_zero(x.type()), x, -x);
+  } else if (x.type().is_float()) {
+    return ir::Call::make(x.type(), "fabs", {x}, ir::Call::PureIntrinsic);
+  } else if (x.type().is_uint()) {
+    return x;
+  } else {
+    LOG(WARNING) << "Warning: Data type " << x.type()
+      <<" not supported for absolute op. Skipping absolute op...";
+    return x;
+  }
+}
+
 }  // namespace tvm
 
 #endif  // TVM_IR_OPERATOR_H_

nnvm/python/nnvm/top/tensor.py

@@ -68,6 +68,10 @@ reg.register_schedule("ceil", _fschedule_broadcast)
 reg.register_pattern("round", OpPattern.ELEMWISE)
 reg.register_schedule("round", _fschedule_broadcast)
 
+# abs
+reg.register_pattern("abs", OpPattern.ELEMWISE)
+reg.register_schedule("abs", _fschedule_broadcast)
+
 # trunc
 reg.register_pattern("trunc", OpPattern.ELEMWISE)
 reg.register_schedule("trunc", _fschedule_broadcast)

nnvm/src/top/tensor/elemwise.cc

@@ -81,6 +81,18 @@ NNVM_REGISTER_ELEMWISE_UNARY_OP(round)
       return Array<Tensor>{ topi::round(inputs[0]) };
 });
 
+// abs
+NNVM_REGISTER_ELEMWISE_UNARY_OP(abs)
+.describe(R"code(Take absolute value of elements of the input.
+)code" NNVM_ADD_FILELINE)
+.set_support_level(3)
+.set_attr<FTVMCompute>(
+  "FTVMCompute", [](const NodeAttrs& attrs,
+                    const Array<Tensor>& inputs,
+                    const Array<Tensor>& out_info) {
+      return Array<Tensor>{ topi::abs(inputs[0]) };
+});
+
 // sigmoid
 NNVM_REGISTER_ELEMWISE_UNARY_OP(sigmoid)
 .describe(R"code(Computes sigmoid.

nnvm/tests/python/compiler/test_top_level3.py

@@ -28,6 +28,10 @@ def test_trunc():
 def test_round():
     check_map(sym.round, np.round)
 
+def test_abs():
+    check_map(sym.abs, np.abs)
+    check_map(sym.abs, np.abs, dtype = "int32")
+    check_map(sym.abs, np.abs, dtype = "int8")
 
 def test_shift():
     n = 3
@@ -40,4 +44,5 @@ if __name__ == "__main__":
     test_floor()
     test_ceil()
     test_round()
+    test_abs()
     test_trunc()

python/tvm/intrin.py

@@ -285,6 +285,22 @@ def trunc(x):
     return call_pure_intrin(x.dtype, "trunc", x)
 
 
+def abs(x):
+    """Get absolute value of the input element-wise.
+
+    Parameters
+    ----------
+    x : Expr
+        Input argument.
+
+    Returns
+    -------
+    y : Expr
+        The result.
+    """
+    return _make.abs(x)
+
+
 def round(x):
     """Round elements of the array to the nearest integer.
 

src/api/api_ir.cc

@@ -7,6 +7,7 @@
 #include <tvm/ir.h>
 #include <ir/IROperator.h>
 #include <tvm/api_registry.h>
+#include <tvm/ir_operator.h>
 
 namespace tvm {
 namespace ir {
@@ -16,6 +17,11 @@ TVM_REGISTER_API("_Var")
     *ret = Variable::make(args[1], args[0]);
   });
 
+TVM_REGISTER_API("make.abs")
+.set_body([](TVMArgs args,  TVMRetValue *ret) {
+    *ret = tvm::abs(args[0]);
+  });
+
 TVM_REGISTER_API("make._range_by_min_extent")
 .set_body([](TVMArgs args,  TVMRetValue *ret) {
     *ret = Range::make_by_min_extent(args[0], args[1]);

src/codegen/intrin_rule_cuda.cc

@@ -64,6 +64,9 @@ TVM_REGISTER_GLOBAL("tvm.intrin.rule.cuda.ceil")
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.cuda.trunc")
 .set_body(DispatchExtern<CUDAMath>);
 
+TVM_REGISTER_GLOBAL("tvm.intrin.rule.cuda.fabs")
+.set_body(DispatchExtern<CUDAMath>);
+
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.cuda.round")
 .set_body(DispatchExtern<CUDAMath>);
 

src/codegen/intrin_rule_metal.cc

@@ -18,6 +18,9 @@ TVM_REGISTER_GLOBAL("tvm.intrin.rule.metal.ceil")
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.metal.trunc")
 .set_body(DispatchExtern<Direct>);
 
+TVM_REGISTER_GLOBAL("tvm.intrin.rule.metal.fabs")
+.set_body(DispatchExtern<Direct>);
+
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.metal.round")
 .set_body(DispatchExtern<Direct>);
 

src/codegen/intrin_rule_opencl.cc

@@ -18,6 +18,9 @@ TVM_REGISTER_GLOBAL("tvm.intrin.rule.opencl.ceil")
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.opencl.trunc")
 .set_body(DispatchExtern<Direct>);
 
+TVM_REGISTER_GLOBAL("tvm.intrin.rule.opencl.fabs")
+.set_body(DispatchExtern<Direct>);
+
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.opencl.round")
 .set_body(DispatchExtern<Direct>);
 

src/codegen/llvm/intrin_rule_llvm.cc

@@ -34,6 +34,9 @@ TVM_REGISTER_GLOBAL("tvm.intrin.rule.llvm.ceil")
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.llvm.trunc")
 .set_body(DispatchLLVMPureIntrin<::llvm::Intrinsic::trunc, 1>);
 
+TVM_REGISTER_GLOBAL("tvm.intrin.rule.llvm.fabs")
+.set_body(DispatchLLVMPureIntrin<::llvm::Intrinsic::fabs, 1>);
+
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.llvm.round")
 .set_body(DispatchLLVMPureIntrin<::llvm::Intrinsic::round, 1>);
 

src/codegen/llvm/intrin_rule_nvptx.cc

@@ -39,6 +39,9 @@ TVM_REGISTER_GLOBAL("tvm.intrin.rule.nvptx.round")
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.nvptx.trunc")
 .set_body(DispatchExternLibDevice);
 
+TVM_REGISTER_GLOBAL("tvm.intrin.rule.nvptx.fabs")
+.set_body(DispatchExternLibDevice);
+
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.nvptx.exp")
 .set_body(DispatchExternLibDevice);
 

src/codegen/llvm/intrin_rule_rocm.cc

@@ -38,6 +38,9 @@ TVM_REGISTER_GLOBAL("tvm.intrin.rule.rocm.round")
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.rocm.trunc")
 .set_body(DispatchLLVMPureIntrin<::llvm::Intrinsic::trunc, 1>);
 
+TVM_REGISTER_GLOBAL("tvm.intrin.rule.rocm.fabs")
+.set_body(DispatchLLVMPureIntrin<::llvm::Intrinsic::fabs, 1>);
+
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.rocm.exp")
 .set_body(DispatchExternOCML);
 

src/codegen/spirv/intrin_rule_spirv.cc

@@ -41,6 +41,9 @@ TVM_REGISTER_GLOBAL("tvm.intrin.rule.vulkan.round")
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.vulkan.trunc")
 .set_body(DispatchGLSLPureIntrin<GLSLstd450Trunc>);
 
+TVM_REGISTER_GLOBAL("tvm.intrin.rule.vulkan.fabs")
+.set_body(DispatchGLSLPureIntrin<GLSLstd450FAbs>);
+
 TVM_REGISTER_GLOBAL("tvm.intrin.rule.vulkan.exp")
 .set_body(DispatchGLSLPureIntrin<GLSLstd450Exp>);
 

topi/include/topi/elemwise.h

@@ -35,6 +35,7 @@ TOPI_DECLARE_UNARY_OP(floor);
 TOPI_DECLARE_UNARY_OP(ceil);
 TOPI_DECLARE_UNARY_OP(round);
 TOPI_DECLARE_UNARY_OP(trunc);
+TOPI_DECLARE_UNARY_OP(abs);
 
 /*!
 * \brief Creates an operation that returns identity of a given tensor

topi/python/topi/math.py

@@ -126,6 +126,23 @@ def trunc(x):
 
 
 @tvm.tag_scope(tag=tag.ELEMWISE)
+def abs(x):
+    """Take absolute value of the input of x, element-wise.
+
+    Parameters
+    ----------
+    x : tvm.Tensor
+        Input argument.
+
+    Returns
+    -------
+    y : tvm.Tensor
+        The result.
+    """
+    return tvm.compute(x.shape, lambda *i: tvm.abs(x(*i)))
+
+
+@tvm.tag_scope(tag=tag.ELEMWISE)
 def round(x):
     """Round elements of x to nearest integer.
 

topi/tests/python/test_topi_math.py

@@ -46,6 +46,7 @@ def test_ewise():
     test_apply(topi.floor, "floor", np.floor, -100, 100)
     test_apply(topi.ceil, "ceil", np.ceil, -100, 100)
     test_apply(topi.trunc, "trunc", np.trunc, -100, 100)
+    test_apply(topi.abs, "fabs", np.abs, -100, 100)
     test_apply(topi.round, "round", np.round, -100, 100)
     test_apply(topi.exp, "exp", np.exp, -1, 1)
     test_apply(topi.tanh, "tanh", np.tanh, -10, 10)