# Primitive Operations Counter

The `Primitive Operations Counter`

is a part of the quantum computer Trace
Simulator. It counts the number of primitive executions used by
every operation invoked in a quantum program. All operations from
`Microsoft.Quantum.Primitive`

are expressed in terms of single qubit rotations,
T gates, single qubit Clifford gates, CNOT gates and measurements of multi-qubit
Pauli observables. Collected statistics are aggregated over the edges of the operations
call graph. Let us now count how many `T`

gates are needed to implement the `CCNOT`

operation.

```
open Microsoft.Quantum.Primitive;
operation CCNOTDriver() : () {
body {
using( qubits = Qubit[3] ) {
CCNOT(qubits[0],qubits[1],qubits[2]);
T(qubits[0]);
}
}
}
```

## Using the Primitive Operations Counter within a C# Program

To check that `CCNOT`

indeed requires 7 `T`

gates and that `CCNOTDriver`

executes 8 `T`

gates we can use the following C# code:

```
// using Microsoft.Quantum.Simulation.Simulators.QCTraceSimulators;
// using System.Diagnostics;
var config = new QCTraceSimulatorConfiguration();
config.usePrimitiveOperationsCounter = true;
var sim = new QCTraceSimulator(config);
var res = CCNOTDriver.Run(sim).Result;
double tCountAll = sim.GetMetric<CCNOTDriver>(PrimitiveOperationsGroupsNames.T);
double tCount = sim.GetMetric<Primitive.CCNOT, CCNOTDriver>(PrimitiveOperationsGroupsNames.T);
```

The first part of the program executes `CCNOTDriver`

. In the second part, we use the method
`QCTraceSimulator.GetMetric`

to get the number of T gates executed by `CCNOTDriver`

:

```
double tCount = sim.GetMetric<Primitive.CCNOT, CCNOTDriver>(PrimitiveOperationsGroupsNames.T);
double tCountAll = sim.GetMetric<CCNOTDriver>(PrimitiveOperationsGroupsNames.T);
```

When `GetMetric`

is called with two type parameters it returns the value of the
metric associated with a given call graph edge. In our example operation
`Primitive.CCNOT`

is called within `CCNOTDriver`

and therefore the call graph contains
the edge `<Primitive.CCNOT,CCNOTDriver>`

.

To get the number of `CNOT`

gates used, we can add the following line:

```
double cxCount = sim.GetMetric<Primitive.CCNOT, CCNOTDriver>(PrimitiveOperationsGroupsNames.CX);
```

Finally, to output all the statistics collected by the gate counter in CSV format we can use the following:

```
string csvSummary = sim.ToCSV()[MetricCalculatorsNames.primitiveOperationsCounter];
```

## See also

- The quantum computer Trace Simulator overview.