From fc26536fcbf0df4251e527ea1e8cd2748224449e Mon Sep 17 00:00:00 2001
From: Daniel Claudino <claudinodc@ornl.gov>
Date: Mon, 5 Aug 2024 17:12:42 +0000
Subject: [PATCH] Optimizer plugins can ignore optimizer failure

Signed-off-by: Daniel Claudino <claudinodc@ornl.gov>
---
 .../nlopt-optimizers/nlopt_optimizer.cpp      | 16 +++++++++++--
 .../optimizers/scipy/scipy_optimizer.cpp      | 23 +++++++++++++++----
 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/quantum/plugins/optimizers/nlopt-optimizers/nlopt_optimizer.cpp b/quantum/plugins/optimizers/nlopt-optimizers/nlopt_optimizer.cpp
index c91aec2ba..3f99ae033 100644
--- a/quantum/plugins/optimizers/nlopt-optimizers/nlopt_optimizer.cpp
+++ b/quantum/plugins/optimizers/nlopt-optimizers/nlopt_optimizer.cpp
@@ -145,6 +145,12 @@ OptResult NLOptimizer::optimize(OptFunction &function) {
     upperBounds = options.get<std::vector<double>>("nlopt-upper-bounds");
   }
 
+  // if fails to find mininum should not throw error
+  bool throwError = true;
+  if (options.keyExists<bool>("throw-error")) {
+    throwError = options.get<bool>("throw-error");
+  }
+
   _opt.set_lower_bounds(lowerBounds);
   _opt.set_upper_bounds(upperBounds);
   _opt.set_maxeval(maxeval);
@@ -171,10 +177,16 @@ OptResult NLOptimizer::optimize(OptFunction &function) {
   try {
     r = _opt.optimize(x, optF);
   } catch (std::exception &e) {
-    xacc::error("NLOpt failed with error code = " + std::to_string(r) + ", " +
+
+    if (throwError) {
+      xacc::error("NLOpt failed with error code = " + std::to_string(r) + ", " +
                 std::string(e.what()));
-  }
+    } else {
+      xacc::warning("NLOpt failed with error code = " + std::to_string(r) + ", " +
+                std::string(e.what()));
+    }
 
+  }
   return OptResult{optF, x};
 }
 
diff --git a/quantum/plugins/optimizers/scipy/scipy_optimizer.cpp b/quantum/plugins/optimizers/scipy/scipy_optimizer.cpp
index 38e4760fe..b7fc7cbb4 100644
--- a/quantum/plugins/optimizers/scipy/scipy_optimizer.cpp
+++ b/quantum/plugins/optimizers/scipy/scipy_optimizer.cpp
@@ -101,6 +101,12 @@ OptResult ScipyOptimizer::optimize(OptFunction &function) {
     x = std::vector<double>(tmpx.begin(), tmpx.end());
   }
 
+  // if fails to find mininum should not throw error
+  bool throwError = true;
+  if (options.keyExists<bool>("throw-error")) {
+    throwError = options.get<bool>("throw-error");
+  }
+
   // here the python stuff starts
   py::list pyInitialParams;
   for (const auto &param : x) {
@@ -152,11 +158,20 @@ OptResult ScipyOptimizer::optimize(OptFunction &function) {
 
     return {optimalValue, optimizedParams};
   } catch (const py::error_already_set &e) {
-    std::cerr << "Python error: " << e.what() << std::endl;
-    throw;
+
+    if (throwError) {
+      xacc::error("Python error: " + std::string(e.what()));
+      throw;
+    }
+    return {};
+
   } catch (const std::exception &e) {
-    std::cerr << "Error: " << e.what() << std::endl;
-    throw;
+  
+    if (throwError) {
+      xacc::error("Error: " + std::string(e.what()));
+      throw;
+    }
+    return {};
   }
 }
 } // namespace xacc