GPU Calc: optimize POISSON

Change-Id: I39d7801da3cce2aaaeafa48fbec615e254691661
Signed-off-by: I-Jui (Ray) Sung <ray@multicorewareinc.com>

sc/source/core/opencl/op_statistical.cxx

@@ -6903,56 +6903,56 @@ void OpPoisson::GenSlidingWindowFunction(
     }
     ss << ")\n";
     ss << "{\n";
-    ss << "    double x,lambda,tmp;\n";
+    ss << "    double x,lambda,tmp,tmp0,tmp1,tmp2;\n";
     ss << "    int bCumulative;\n";
     ss << "    int gid0=get_global_id(0);\n";
-#ifdef ISNAN
-    FormulaToken *tmpCur0 = vSubArguments[0]->GetFormulaToken();
-    const formula::SingleVectorRefToken*tmpCurDVR0= dynamic_cast<const
-    formula::SingleVectorRefToken *>(tmpCur0);
-    FormulaToken *tmpCur1 = vSubArguments[1]->GetFormulaToken();
-    const formula::SingleVectorRefToken*tmpCurDVR1= dynamic_cast<const
-    formula::SingleVectorRefToken *>(tmpCur1);
-    FormulaToken *tmpCur2 = vSubArguments[2]->GetFormulaToken();
-    const formula::SingleVectorRefToken*tmpCurDVR2= dynamic_cast<const
-    formula::SingleVectorRefToken *>(tmpCur2);
-    ss << "    int buffer_x_len = ";
-    ss << tmpCurDVR0->GetArrayLength();
-    ss << ";\n";
-    ss << "     int buffer_lambda_len = ";
-    ss << tmpCurDVR1->GetArrayLength();
-    ss << ";\n";
-    ss << "    int buffer_bCumulative_len = ";
-    ss << tmpCurDVR2->GetArrayLength();
-    ss << ";\n";
+    size_t i = vSubArguments.size();
+    ss <<"\n    ";
+    for (i = 0; i < vSubArguments.size(); i++)
+    {
+        FormulaToken *pCur = vSubArguments[i]->GetFormulaToken();
+        assert(pCur);
+        if (pCur->GetType() == formula::svSingleVectorRef)
+        {
+#ifdef  ISNAN
+                const formula::SingleVectorRefToken* pSVR =
+                dynamic_cast< const formula::SingleVectorRefToken* >(pCur);
+            ss << "if (gid0 < " << pSVR->GetArrayLength() << "){\n";
 #endif
-#ifdef ISNAN
-    ss <<"    if((gid0)>=buffer_x_len || isNan(";
-    ss << vSubArguments[0]->GenSlidingWindowDeclRef();
-    ss <<"))\n";
-    ss <<"        x = 0;\n";
-    ss <<"    else \n";
+        }
+        else if (pCur->GetType() == formula::svDouble)
+        {
+#ifdef  ISNAN
+            ss << "{\n";
 #endif
-    ss <<"         x ="<<vSubArguments[0]->GenSlidingWindowDeclRef();
-    ss << ";\n";
-#ifdef ISNAN
-    ss <<"    if((gid0)>=buffer_lambda_len || isNan(";
-    ss << vSubArguments[1]->GenSlidingWindowDeclRef();
-    ss <<"))\n";
-    ss <<"        lambda = 0;\n";
-    ss <<"    else \n";
+        }
+        else
+        {
+#ifdef  ISNAN
 #endif
-    ss <<"        lambda ="<<vSubArguments[1]->GenSlidingWindowDeclRef();
-    ss << ";\n";
-#ifdef ISNAN
-    ss <<"    if((gid0)>=buffer_bCumulative_len || isNan(";
-    ss << vSubArguments[2]->GenSlidingWindowDeclRef();
-    ss <<"))\n";
-    ss <<"    bCumulative = 0;\n";
-    ss <<"else \n";
+        }
+#ifdef  ISNAN
+        if(ocPush==vSubArguments[i]->GetFormulaToken()->GetOpCode())
+        {
+            ss << "    if (isNan(";
+            ss << vSubArguments[i]->GenSlidingWindowDeclRef();
+            ss << "))\n";
+            ss << "        tmp"<<i<<"= 0;\n";
+            ss << "    else\n";
+            ss << "        tmp"<<i<<"=\n";
+            ss << vSubArguments[i]->GenSlidingWindowDeclRef();
+            ss << ";\n}\n";
+        }
+        else
+        {
+            ss << "tmp"<<i<<"="<<vSubArguments[i]->GenSlidingWindowDeclRef();
+            ss <<";\n";
+        }
 #endif
-    ss <<"     bCumulative ="<<vSubArguments[2]->GenSlidingWindowDeclRef();
-    ss << ";\n";
+    }
+    ss << "    x = floor(tmp0);\n";
+    ss << "    lambda = tmp1;\n";
+    ss << "    bCumulative = tmp2;\n ";
     ss << "    if (!bCumulative)\n";
     ss << "    {\n";
     ss << "        if(lambda == 0.0)\n";
@@ -6970,7 +6970,7 @@ void OpPoisson::GenSlidingWindowFunction(
     ss << "            {\n";
     ss << "                double fPoissonVar = 1.0;\n";
     ss << "                for ( int f = 0; f < x; ++f )\n";
-    ss << "                    fPoissonVar *= lambda / ( (double)f + 1.0 );\n";
+    ss << "          fPoissonVar *= lambda * pow(( (double)f + 1.0 ),-1);\n";
     ss << "                tmp = ( fPoissonVar * exp( -lambda ) );\n";
     ss << "                return tmp;\n";
     ss << "            }\n";
@@ -7002,7 +7002,7 @@ void OpPoisson::GenSlidingWindowFunction(
     ss << "                     int nEnd = (int) (x + 0.5);\n";
     ss << "                     for (int i = 1; i <= nEnd; i++)\n";
     ss << "                     {\n";
-    ss << "                         fSummand = (fSummand*lambda)/(double)i;\n";
+    ss << "                fSummand = (fSummand*lambda)*pow((double)i,-1);\n";
     ss << "                         fSum += fSummand;\n";
     ss << "                     }\n";
     ss << "                     tmp = fSum;\n";

sc/source/core/opencl/opinlinefun_statistical.cxx

@@ -900,9 +900,9 @@ std::string lcl_GetGammaHelper =
 "   double fGamma = lcl_getLanczosSum(fZ);\n"
 "   double fg = 6.024680040776729583740234375;\n"
 "   double fZgHelp = fZ + fg - 0.5;\n"
-"   double fHalfpower = pow( fZgHelp, fZ / 2 - 0.25);\n"
+"   double fHalfpower = pow( fZgHelp, fZ*pow(2,-1.0) - 0.25);\n"
 "   fGamma *= fHalfpower;\n"
-"   fGamma /= exp(fZgHelp);\n"
+"   fGamma = fGamma*pow(exp(fZgHelp),-1.0);\n"
 "   fGamma *= fHalfpower;\n"
 "   fGamma = 120.4;\n"
 "   if (fZ <= 20.0 && fZ == (int)fZ)\n"