#settings

Per-file simulator options. Each line overrides one key; omitted keys keep their defaults. The Settings modal and gear menu write the same lines back into your source when you save.

Reference

Key	Default	Type	What it does
`Scheduling`	`"always"`	enum	Gate packing mode. See Scheduling.
`MaxQubits`	`12`	int (2-24)	Highest wire index is MaxQubits − 1. The state vector needs 16 bytes per amplitude, so 24 qubits use 256 MB; above about 12 qubits the probability panels list the most likely outcomes and the density matrix view keeps the first 10 wires.
`VisibleQubits`	`2`	int	How many qubit rows the circuit builder shows.
`Zoom`	`100%`	percent or multiplier	Circuit builder zoom: 50%, 1, 1.5, 2.
`AutoAdjustVisibleQubits`	`true`	bool	Grow visible rows when code uses higher indices.
`DecimalPlaces`	`2`	int (0-12)	Digits for amplitudes and probabilities.
`AutoRun`	`true`	bool	Re-run the circuit when code changes.
`UseOptimizedGates`	`true`	bool	Use optimized decompositions where available.
`UseOptimizedSweep`	`true`	bool	Faster sweep runs when stepping combos or running the full sweep batch.
`StepByStep`	`false`	bool	Circuit builder step scrubber and play controls.
`ShowGateParams`	`true`	bool	Angle labels on rotation tiles.
`ShowConditionalBranches`	`"none"`	none \| some \| all	If/else markers on the circuit. none hides them, some shows branches that contain gates, all shows every marker.
`ShowEvaluatedLabels`	`true`	bool	Show evaluated LOOP counts and wire lists on blocks.
`GateParamAngleUnit`	`"degrees"`	degrees \| radians \| piradians	Unit for labels drawn on gates.
`CodeAngleUnit`	`"piradians"`	degrees \| radians \| piradians	Default unit for bare numbers in source code.
`SymbolicNotation`	`false`	bool	Prefer √(½) style in state displays.
`HideNegligibles`	`true`	bool	Drop near-zero amplitudes from the state vector.
`SortBy`	`"probability"`	probability \| label	Basis-state sort key.
`SortOrder`	`"desc"`	asc \| desc	Sort direction for basis states.
`NmrSample`	`"chloroform"`	sample key	Spin system for the NMR Analysis tab. Keys are listed on the NMR sample library page.
`NmrField`	`11.74`	tesla	Static field B0 for the NMR Analysis tab (500 MHz for protons).
`NmrRf`	`0.587`	millitesla	RF field amplitude B1; sets pulse lengths (0.587 mT is a 10 µs proton 90° pulse).
`NmrT1`	`2`	seconds	Longitudinal relaxation time used for acquisition lengths on the NMR tab.
`NmrT2`	`1`	seconds	Transverse relaxation time; sets the line width 1/(πT2) on the NMR tab.
`NmrPulseShape`	`"square"`	square \| gaussian \| sinc \| hermite	Envelope drawn and timed for RF pulses on the NMR tab.
`NmrReadout`	`"pulse"`	pulse \| none	"pulse" applies a 90° readout pulse before acquisition; "none" acquires the state as it is.
`NmrChannel`	`(first isotope)`	isotope	Which isotope the receiver listens to, for example 1H or 13C.

Full header example

Only non-default lines need to appear in practice - the block below shows every key for copy/paste:

#settings Scheduling "always"
#settings MaxQubits 12
#settings VisibleQubits 2
#settings Zoom 100%
#settings AutoAdjustVisibleQubits true
#settings DecimalPlaces 2
#settings AutoRun true
#settings UseOptimizedGates true
#settings UseOptimizedSweep true
#settings StepByStep false
#settings ShowGateParams true
#settings ShowConditionalBranches "none"
#settings ShowEvaluatedLabels true
#settings GateParamAngleUnit "degrees"
#settings CodeAngleUnit "piradians"
#settings SymbolicNotation false
#settings HideNegligibles true
#settings SortBy "probability"
#settings SortOrder "desc"
#settings NmrSample "chloroform"
#settings NmrField 11.74
#settings NmrRf 0.587
#settings NmrT1 2
#settings NmrT2 1
#settings NmrPulseShape "square"
#settings NmrReadout "pulse"
#settings NmrChannel (first isotope)

Scheduling

See the dedicated Scheduling page. Quick version: "always" packs gates aggressively; "never" puts every gate in its own column.

StepByStep

Off by default. When true, the circuit builder shows the step scrubber, play button, and editable step counter (0 / N through N / N). Data Analysis always has its own step timeline regardless of this flag.