some v4 patches

.github/workflows/audit.yml

@@ -14,9 +14,11 @@ on:
   push:
     branches:
       - main
+      - devel
   pull_request:
     branches:
       - main
+      - devel
 
 
 jobs:

.github/workflows/compile.yml

@@ -20,9 +20,11 @@ on:
   push:
     branches:
       - main
+      - devel
   pull_request:
     branches:
       - main
+      - devel
 
 
 jobs:

.github/workflows/doc.yml

@@ -15,7 +15,7 @@ permissions:
 on:
   push:
     branches:
-      - master
+      - main
   workflow_dispatch:
 
 

.github/workflows/test_free.yml

@@ -14,9 +14,11 @@ on:
   push:
     branches:
       - main
+      - devel
   pull_request:
     branches:
       - main
+      - devel
 
 
 jobs:

.github/workflows/test_paid.yml

@@ -19,7 +19,7 @@ name: test (paid, accelerated)
 
 # @todo
 # this workflow can only be run on the 'default' 
-# branch (i.e. master) when manually triggered by 
+# branch (i.e. main) when manually triggered by 
 # github actions, so as not to incur unexpected
 # costs. I want for this to be automatically 
 # enqueued but not run in a PR, requiring manual

quest/src/api/operations.cpp

@@ -1135,8 +1135,8 @@ void applyFirstOrderTrotter(Qureg qureg, PauliStrSum sum, qreal angle, bool reve
 
     for (qindex i=0; i<sum.numTerms; i++) {
         int j = reverse? sum.numTerms - i - 1 : i;
-        qreal arg = 2 * angle * std::real(sum.coeffs[j]);  // 2 undoes Gadget convention
-        applyPauliGadget(qureg, sum.strings[j], arg); // re-validates, grr
+        qreal arg = 2 * angle * std::real(sum.coeffs[j]); // 2 undoes Gadget convention
+        applyPauliGadget(qureg, sum.strings[j], arg); // caller disabled valiation therein
     }
 }
 
@@ -1172,16 +1172,27 @@ void applyTrotterizedPauliStrSumGadget(Qureg qureg, PauliStrSum sum, qreal angle
     validate_pauliStrSumIsHermitian(sum, __func__);
     validate_trotterParams(qureg, order, reps, __func__);
 
-    /// @todo
-    /// the accuracy of Trotterisation is greatly improved by randomisation
-    /// or (even sub-optimal) grouping into commuting terms. Should we 
-    /// implement these here or into another function?
-
+    // exp(i angle sum) = identity when angle=0
     if (angle == 0)
         return;
 
+    // record validation state then disable to avoid repeated
+    // re-validations in each invoked applyPauliGadget() below
+    bool wasValidationEnabled = validateconfig_isEnabled();
+    validateconfig_disable();
+
+    // perform sequence of applyPauliGadget()
     for (int r=0; r<reps; r++)
         applyHigherOrderTrotter(qureg, sum, angle/reps, order);
+
+    // potentially restore validation
+    if (wasValidationEnabled)
+        validateconfig_enable();
+
+    /// @todo
+    /// the accuracy of Trotterisation is greatly improved by randomisation
+    /// or (even sub-optimal) grouping into commuting terms. Should we 
+    /// implement these above or into another function?
 }
 
 } // end de-mangler

quest/src/core/printer.cpp

@@ -339,6 +339,14 @@ template string printer_toStr<double>(complex<double> num);
 template string printer_toStr<long double>(complex<long double> num);
 
 
+// explicit qreal overload so that real sig-figs can be changed
+string printer_toStr(qreal num) {
+
+    // uses user-set significant figures
+    return floatToStr(num);
+}
+
+
 // alias as toStr() just for internal brevity
 // (this seems backward; ordinarily we would define toStr() as
 // the templated inner-function and define concretely-typed public
@@ -776,11 +784,12 @@ MatrixQuadrantInds getTruncatedMatrixQuadrantInds(qindex numRows, qindex numCols
 
     MatrixQuadrantInds inds;
 
-    // according to the user-set truncations
-    qindex maxNumLeftCols  = global_maxNumPrintedCols / 2; // floors
-    qindex maxNumRightCols = global_maxNumPrintedCols - maxNumLeftCols;
-    qindex maxNumUpperRows = global_maxNumPrintedRows / 2; // floors
-    qindex maxNumLowerRows = global_maxNumPrintedRows - maxNumUpperRows;
+    // find maximum size of matrix quadrants according to user-truncatins.
+    // Choose right & lower first so that When num=odd, extra left & upper elem is shown
+    qindex maxNumRightCols  = global_maxNumPrintedCols / 2; // floors
+    qindex maxNumLeftCols = global_maxNumPrintedCols - maxNumRightCols;
+    qindex maxNumLowerRows = global_maxNumPrintedRows / 2; // floors
+    qindex maxNumUpperRows = global_maxNumPrintedRows - maxNumLowerRows;
 
     // may be ignored (and will unimportantly underflow when not truncating)
     inds.rightStartCol = numCols - maxNumRightCols;

quest/src/core/printer.hpp

@@ -21,6 +21,8 @@
 #include <sstream>
 #include <type_traits>
 
+// beware that files including this header receive all these
+// namespace items; a worthwhile evil to keep this readable
 using std::tuple;
 using std::string;
 using std::vector;
@@ -70,12 +72,18 @@ template<typename T>
 string printer_toStr(T expr) {
 
     // write to buffer (rather than use to_string()) so that floating-point numbers
-    // are automatically converted to scientific notation when necessary
+    // are automatically converted to scientific notation when necessary. Beware
+    // that the user configured significant figures are not reflected here.
+
     std::ostringstream buffer;
     buffer << expr;
     return buffer.str();
 }
 
+// explicit qreal version of above, affected by user-set significant figures
+string printer_toStr(qreal num);
+
+
 
 /*
  * SUBSTRING PREPARATION

quest/src/core/validation.cpp

@@ -1066,8 +1066,11 @@ namespace report {
 
 void default_inputErrorHandler(const char* func, const char* msg) {
 
-    // safe to call even before MPI has been setup, and ignores user-set trailing newlines
-    print(string("")
+    // safe to call even before MPI has been setup, and ignores user-set trailing newlines.
+    // It begins with \n to interrupt half-printed lines (when trailing newlines are set to
+    // 0 via setNumReportedNewlines(0)), for visual clarity. Note that user's overriding
+    // functions might not think to print an initial newline but oh well!
+    print(string("\n")
         + "QuEST encountered a validation error during function " 
         + "'" + func + "':\n" + msg + "\n"
         + "Exiting...\n");