[quantinuum] Add new argument for maximum number of qubits

.github/workflows/integration_tests.yml

@@ -759,7 +759,7 @@ jobs:
                 if [[ "$filename" == *.cpp ]]; then
                   if [[ "$filename" == *"quantinuum_ng/"* ]]; then
                     echo "### Running Quantinuum-NG test" >> $GITHUB_STEP_SUMMARY
-                    nvq++ -v $filename --target quantinuum --quantinuum-machine Helios-1E --quantinuum-project ${{ secrets.QUANTINUUM_NEXUS_PROJECT_ID }} --quantinuum-max-cost 10 --quantinuum-noisy-simulation false
+                    nvq++ -v $filename --target quantinuum --quantinuum-machine Helios-1E --quantinuum-project ${{ secrets.QUANTINUUM_NEXUS_PROJECT_ID }} --quantinuum-max-cost 10 --quantinuum-max-qubits 7 --quantinuum-noisy-simulation false
                   else
                     echo "### Running standard Quantinuum test" >> $GITHUB_STEP_SUMMARY
                     nvq++ -v $filename -DSYNTAX_CHECK --target quantinuum --quantinuum-machine H2-1SC --quantinuum-project ${{ secrets.QUANTINUUM_NEXUS_PROJECT_ID }}

runtime/cudaq/platform/default/rest/helpers/quantinuum/QuantinuumServerHelper.cpp

@@ -43,6 +43,8 @@ class QuantinuumServerHelper : public ServerHelper, public QirServerHelper {
   std::string machine = "H2-1SC";
   /// @brief Max HQC cost
   std::optional<int> maxCost;
+  /// @brief Maximum number of qubits
+  std::optional<int> maxQubits;
   /// @brief Enable/disable noisy simulation on emulator.
   std::optional<bool> noisySim;
   /// @brief The type of simulator to use if machine is a simulator.
@@ -124,6 +126,14 @@ class QuantinuumServerHelper : public ServerHelper, public QirServerHelper {
         throw std::runtime_error("max_cost must be a positive integer.");
     }
 
+    // Set max qubits
+    iter = backendConfig.find("max_qubits");
+    if (iter != backendConfig.end()) {
+      maxQubits = std::stoi(iter->second);
+      if (maxQubits.value() < 1)
+        throw std::runtime_error("max_qubits must be a positive integer.");
+    }
+
     // Noisy simulation
     iter = backendConfig.find("noisy_simulation");
     if (iter != backendConfig.end()) {
@@ -368,20 +378,36 @@ QuantinuumServerHelper::createJob(std::vector<KernelExecution> &circuitCodes) {
         "QuantinuumConfig";
     j["data"]["attributes"]["definition"]["backend_config"]["device_name"] =
         machine;
-    // On Helios devices, we need to specify max-cost unless it's a syntax
-    // checker
-    if (machine.starts_with("Helios") && !machine.ends_with("SC") &&
-        !maxCost.has_value())
-      throw std::runtime_error(
-          "Please specify a maximum cost (`--quantinuum-max-cost <val>` when "
-          "compiling with nvq++ or `max_cost=<val>` in Python `set_target`) "
-          "when using device: " +
-          machine);
+    // On Helios devices, we need to specify max-cost and max-qubits unless it's
+    // a syntax checker
+    if (machine.starts_with("Helios") && !machine.ends_with("SC")) {
+      std::vector<std::string> errors;
+      if (!maxCost.has_value())
+        errors.push_back("Please specify maximum HQC cost "
+                         "(`--quantinuum-max-cost <val>` when compiling with "
+                         "nvq++ or `max_cost=<val>` in Python `set_target`)");
+      if (!maxQubits.has_value())
+        errors.push_back(
+            "Please specify maximum number of qubits (`--quantinuum-max-qubits "
+            "<val>` when compiling with nvq++ or `max_qubits=<val>` in Python "
+            "`set_target`)");
+      if (!errors.empty())
+        throw std::runtime_error(
+            fmt::format("Missing required configuration for device '{}': {}",
+                        machine, fmt::join(errors, "; ")));
+    }
 
     if (maxCost.has_value())
       j["data"]["attributes"]["definition"]["backend_config"]["max_cost"] =
           maxCost.value();
 
+    if (maxQubits.has_value()) {
+      j["data"]["attributes"]["definition"]["backend_config"]
+       ["compiler_options"] = ServerMessage::object();
+      j["data"]["attributes"]["definition"]["backend_config"]
+       ["compiler_options"]["max-qubits"] = maxQubits.value();
+    }
+
     if (noisySim.has_value() && machine.ends_with("E"))
       j["data"]["attributes"]["definition"]["backend_config"]
        ["noisy_simulation"] = noisySim.value() ? "true" : "false";

runtime/cudaq/platform/default/rest/helpers/quantinuum/quantinuum.yml

@@ -67,6 +67,11 @@ target-arguments:
     type: string
     platform-arg: max_cost
     help-string: "Specify the max HQC cost for a job submission."
+  - key: max-qubits
+    required: false
+    type: string
+    platform-arg: max_qubits
+    help-string: "Specify the maximum number of qubits for a job submission."
   - key: noisy-simulation
     required: false
     type: string