GPU Calc: Optimized COMBINA

AMLOEXT-259

Change-Id: I8c5330a92ff0065bf9f51ea374b8aa686fdebc3c
Signed-off-by: haochen <haochen@multicorewareinc.com>
Signed-off-by: Wei Wei <weiwei@multicorewareinc.com>
Signed-off-by: I-Jui (Ray) Sung <ray@multicorewareinc.com>

sc/source/core/opencl/op_math.cxx

@@ -200,19 +200,19 @@ void OpCombina::GenSlidingWindowFunction(std::stringstream &ss,
     }
     ss << "    arg0 = trunc(arg0);\n";
     ss << "    arg1 = trunc(arg1);\n";
-    ss << "    if(arg0 < arg1 || arg0 < 0 || arg1 < 0)\n";
-    ss << "        tem = -1;\n";
+    ss << "    if(arg0 >= arg1 && arg0 > 0 && arg1 > 0)\n";
+    ss << "        tem = bik(arg0+arg1-1,arg1);\n"; 
     ss << "    else if(arg0 == 0 && arg1 == 0)\n";
     ss << "        tem = 0;\n";
     ss << "    else if(arg0 > 0 && arg1 == 0)\n";
     ss << "        tem = 1;\n";
     ss << "    else\n";
-    ss << "        tem = bik(arg0+arg1-1,arg1);\n";
-    ss << "    double k = tem - trunc(tem);\n";
-    ss << "    if(k < 0.5)\n";
+    ss << "        tem = -1;\n";
+    ss << "    double i = tem - trunc(tem);\n";
+    ss << "    if(i < 0.5)\n";
     ss << "        tem = trunc(tem);\n";
     ss << "    else\n";
-    ss << "        tem = trunc(tem) + 1;";
+    ss << "        tem = trunc(tem) + 1;\n";
     ss << "    return tem;\n";
     ss << "}";
 }

sc/source/core/opencl/opinlinefun_math.hxx

@@ -25,16 +25,18 @@ std::string bikDecl = "double bik(double n,double k);\n";
 std::string bik =
 "double bik(double n,double k)\n"
 "{\n"
-"    double nVal = n/k;\n"
+"    double nVal1 = n;\n"
+"    double nVal2 = k;\n"
 "    n = n - 1;\n"
 "    k = k - 1;\n"
 "    while (k > 0)\n"
 "    {\n"
-"        nVal = nVal * ( n/k );\n"
+"        nVal1 = nVal1 * n;\n"
+"        nVal2 = nVal2 * k;\n"
 "        k = k - 1;\n"
 "        n = n - 1;\n"
 "    }\n"
-"    return nVal;\n"
+"    return (nVal1 / nVal2);\n"
 "}\n";
 
 std::string local_cothDecl = "double local_coth(double n);\n";