Merge pull request #663 from quantumlib/fix-sampling

Fix sampling.

Author: sergeisakov

lib/statespace_avx.h

@@ -382,8 +382,8 @@ class StateSpaceAVX :
 
       for (uint64_t k = 0; k < size; ++k) {
         for (unsigned j = 0; j < 8; ++j) {
-          auto re = p[16 * k + j];
-          auto im = p[16 * k + 8 + j];
+          double re = p[16 * k + j];
+          double im = p[16 * k + 8 + j];
           norm += re * re + im * im;
         }
       }
@@ -396,15 +396,19 @@ class StateSpaceAVX :
 
       for (uint64_t k = 0; k < size; ++k) {
         for (unsigned j = 0; j < 8; ++j) {
-          auto re = p[16 * k + j];
-          auto im = p[16 * k + 8 + j];
+          double re = p[16 * k + j];
+          double im = p[16 * k + 8 + j];
           csum += re * re + im * im;
           while (rs[m] < csum && m < num_samples) {
             bitstrings.emplace_back(8 * k + j);
             ++m;
           }
         }
       }
+
+      for (; m < num_samples; ++m) {
+        bitstrings.emplace_back((uint64_t{1} << state.num_qubits()) - 1);
+      }
     }
 
     return bitstrings;

lib/statespace_avx512.h

@@ -333,8 +333,8 @@ class StateSpaceAVX512 :
 
       for (uint64_t k = 0; k < size; ++k) {
         for (unsigned j = 0; j < 16; ++j) {
-          auto re = p[32 * k + j];
-          auto im = p[32 * k + 16 + j];
+          double re = p[32 * k + j];
+          double im = p[32 * k + 16 + j];
           norm += re * re + im * im;
         }
       }
@@ -347,15 +347,19 @@ class StateSpaceAVX512 :
 
       for (uint64_t k = 0; k < size; ++k) {
         for (unsigned j = 0; j < 16; ++j) {
-          auto re = p[32 * k + j];
-          auto im = p[32 * k + 16 + j];
+          double re = p[32 * k + j];
+          double im = p[32 * k + 16 + j];
           csum += re * re + im * im;
           while (rs[m] < csum && m < num_samples) {
             bitstrings.emplace_back(16 * k + j);
             ++m;
           }
         }
       }
+
+      for (; m < num_samples; ++m) {
+        bitstrings.emplace_back((uint64_t{1} << state.num_qubits()) - 1);
+      }
     }
 
     return bitstrings;

lib/statespace_basic.h

@@ -203,8 +203,8 @@ class StateSpaceBasic :
       const fp_type* p = state.get();
 
       for (uint64_t k = 0; k < size; ++k) {
-        auto re = p[2 * k];
-        auto im = p[2 * k + 1];
+        double re = p[2 * k];
+        double im = p[2 * k + 1];
         norm += re * re + im * im;
       }
 
@@ -215,14 +215,18 @@ class StateSpaceBasic :
       bitstrings.reserve(num_samples);
 
       for (uint64_t k = 0; k < size; ++k) {
-        auto re = p[2 * k];
-        auto im = p[2 * k + 1];
+        double re = p[2 * k];
+        double im = p[2 * k + 1];
         csum += re * re + im * im;
         while (rs[m] < csum && m < num_samples) {
           bitstrings.emplace_back(k);
           ++m;
         }
       }
+
+      for (; m < num_samples; ++m) {
+        bitstrings.emplace_back((uint64_t{1} << state.num_qubits()) - 1);
+      }
     }
 
     return bitstrings;

lib/statespace_sse.h

@@ -342,8 +342,8 @@ class StateSpaceSSE :
 
       for (uint64_t k = 0; k < size; ++k) {
         for (unsigned j = 0; j < 4; ++j) {
-          auto re = p[8 * k + j];
-          auto im = p[8 * k + 4 + j];
+          double re = p[8 * k + j];
+          double im = p[8 * k + 4 + j];
           norm += re * re + im * im;
         }
       }
@@ -356,15 +356,19 @@ class StateSpaceSSE :
 
       for (uint64_t k = 0; k < size; ++k) {
         for (unsigned j = 0; j < 4; ++j) {
-          auto re = p[8 * k + j];
-          auto im = p[8 * k + 4 + j];
+          double re = p[8 * k + j];
+          double im = p[8 * k + 4 + j];
           csum += re * re + im * im;
           while (rs[m] < csum && m < num_samples) {
             bitstrings.emplace_back(4 * k + j);
             ++m;
           }
         }
       }
+
+      for (; m < num_samples; ++m) {
+        bitstrings.emplace_back((uint64_t{1} << state.num_qubits()) - 1);
+      }
     }
 
     return bitstrings;