# From the bindings/python directory:
pip install maturin
maturin develop --release

# Verify installation:
python -c "import entropyk; print(entropyk.Pressure(bar=1.0))"

Basic Usage

import entropyk

# ── 1. Physical Types (type-safe units) ──

p = entropyk.Pressure(bar=12.0)
print(p.to_kpa())        # 1200.0 kPa
print(p.to_pascals())    # 1200000.0 Pa

t = entropyk.Temperature(celsius=45.0)
print(t.to_kelvin())     # 318.15 K

h = entropyk.Enthalpy(kj_per_kg=420.0)
m = entropyk.MassFlow(kg_per_s=0.05)

# Arithmetic
dp = entropyk.Pressure(bar=10.0) - entropyk.Pressure(bar=3.0)


# ── 2. Build a Refrigeration Cycle ──

system = entropyk.System()

comp = system.add_component(entropyk.Compressor(efficiency=0.85))
cond = system.add_component(entropyk.Condenser(ua=5000.0))
exv  = system.add_component(entropyk.ExpansionValve())
evap = system.add_component(entropyk.Evaporator(ua=3000.0))

system.add_edge(comp, cond)
system.add_edge(cond, exv)
system.add_edge(exv, evap)
system.add_edge(evap, comp)
system.finalize()


# ── 3. Solve ──

config = entropyk.FallbackConfig(
    newton=entropyk.NewtonConfig(max_iterations=200, tolerance=1e-6),
    picard=entropyk.PicardConfig(max_iterations=500, relaxation=0.5),
)

try:
    result = config.solve(system)
    print(f"Converged in {result.iterations} iterations")
    print(f"State: {result.state_vector}")
except entropyk.TimeoutError:
    print("Solver timed out")
except entropyk.SolverError as e:
    print(f"Solver failed: {e}")

API Reference

Physical Types

Type	Constructors	Conversions
`Pressure`	`pa=`, `bar=`, `kpa=`, `psi=`	`to_pascals()`, `to_bar()`, `to_kpa()`, `to_psi()`
`Temperature`	`kelvin=`, `celsius=`, `fahrenheit=`	`to_kelvin()`, `to_celsius()`, `to_fahrenheit()`
`Enthalpy`	`j_per_kg=`, `kj_per_kg=`	`to_j_per_kg()`, `to_kj_per_kg()`
`MassFlow`	`kg_per_s=`, `g_per_s=`	`to_kg_per_s()`, `to_g_per_s()`

All types support: __repr__, __str__, __float__, __eq__, __add__, __sub__

Components

Component	Constructor	Description
`Compressor`	`(m1..m10, speed_rpm, displacement, efficiency, fluid)`	AHRI 540 performance model
`Condenser`	`(ua)`	Heat rejection coil
`Evaporator`	`(ua)`	Heat absorption coil
`Economizer`	`(ua)`	Internal heat exchanger
`ExpansionValve`	`(fluid, opening)`	Isenthalpic throttling
`Pipe`	`(length, diameter, fluid, density, viscosity, roughness)`	Darcy-Weisbach pressure drop
`Pump`	`(pressure_rise_pa, efficiency)`	Liquid pump
`Fan`	`(pressure_rise_pa, efficiency)`	Air fan
`FlowSplitter`	`(n_outlets)`	Flow distribution
`FlowMerger`	`(n_inlets)`	Flow recombination
`FlowSource`	`(pressure_pa, temperature_k)`	Boundary source
`FlowSink`	`()`	Boundary sink

Solver

# Newton-Raphson (fast convergence)
config = entropyk.NewtonConfig(max_iterations=100, tolerance=1e-6, line_search=True)

# Picard / Sequential Substitution (more robust)
config = entropyk.PicardConfig(max_iterations=500, tolerance=1e-4, relaxation=0.5)

# Fallback (Newton → Picard on divergence)
config = entropyk.FallbackConfig(newton=newton_cfg, picard=picard_cfg)

result = config.solve(system)  # Returns ConvergedState

Exceptions

EntropykError (base)
├── SolverError
│   ├── TimeoutError
│   └── ControlSaturationError
├── FluidError
├── ComponentError
├── TopologyError
└── ValidationError

Running Tests

cd bindings/python
maturin develop
pytest tests/ -v

Examples

examples/simple_cycle.py — Build and solve a refrigeration cycle
examples/migration_from_tespy.py — TESPy → Entropyk migration guide